Powerware SOLA 4000 manual UPS System Structure, Rectifier/Battery Charger

SOLA 4000 - General System Description

1 UPS Assembly

1.2 UPS System Structure

The basic SOLA 4000 power supply unit is an ac/dc/ac converter; the block diagram: Figure 1.1 illustrates six essential functional components:

•Rectifier/battery charger (6 pulse) (RECT.)

•Battery (BATT.)

•Inverter (INV.)

•Static inverter switch (SSI)

•Static bypass (SSB)

•Maintenance bypass (IBY)

All components are located in a single housing. They are explained in detail on the following pages.The control electronics of the rectifier, inverter and static bypass sections are completely inde- pendent of each other. i.e. a failure in any one section will not cause a failure in another section.

1.3 Rectifier/Battery Charger

In the standard configuration the charger is a three phase/6 pulse rectifier that converts ac voltage to dc voltage. No isolation trans- former is used and the rectifier is connected to the mains via the commutation chokes which reduce the mains distortion created by the rectifier. The dc output of the rectifier feeds the inverter and the battery. The battery is connected to the rectifier through a satura- tion choke which reduces ac ripple current to the battery, thus ensuring the maximum battery life-time.

The rectifier is designed to feed both the inverter at maximum load conditions and simultaneously the battery with maximum charging current. Normally, the battery voltage is constantly regulated at 432 V dc (floating charge, maintenance-free lead battery, 2.25 volts per cell). The rectifier's recharge characteristic is of the I/U type. This means that the recharging current limitation is accomplished by reduction of the dc voltage, thus assuring that the batteries will not be damaged by excessive charging currents.

A12-pulse rectifier is optional and requires the addition of a sec- ond rectifier bridge inside the UPS cabinet and a phase shifting transformer in a separate cabinet.

FIG. 1.3 - 12-pulse Rectifier Block-Diagram

JUE 401264 7