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1.0 Introduction

1.1 Overview

This equipment is a high-performance, line-interactive, uninterruptible
power source (UPS) designed to provide clean, reliable, AC power to
computer loads. The UPS’s line-interactive circuit topology (see figure
below) offers excellent efficiency, on-line voltage regulation, and fast utility
fault response.
The UPS’s DC-to-AC inverter is always connected to the output and when
operating on-line, part of the inverter circuitry is used “in reverse” to
continuously maintain optimum float charge on the battery. The inverter
also protects the load from surges and EMI/RFI noise as part of an ad-
vanced hybrid surge suppression and filtering network.
A unique mode of operation, called SmartBoost, regulates the load voltage
by compensating for brownouts or sags without drawing power from the
UPS’s battery. The UPS continuously monitors the line for utility failure
and prepares the inverter frequency for synchronous transfer of the load.
When a utility voltage failure occurs such as a blackout, severe brownout,
or an overvoltage condition, the UPS transfers the load to battery power.
Transfer to “on-battery” operation typically takes place within 2 millisec-
onds. The inverter’s output voltage waveshape is a low distortion sine
wave. Resynchronization and transfer back to on-line operation is auto-
matic when the line voltage returns to within normal limits.
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Line interactive UPS block diagram