General Description, Features, Design Concept

Chapter 1 General Description

This chapter briefly introduces the features, design concept and operation mode of the HIPULSE U UPS.

1.1 Features

The HIPULSE U UPS is connected between a critical load, such as a computer, and its 3-phase mains power supply. Being designed to furnish a well regulated 3-phase output power supply under all rated load and input supply conditions, the system offers the user the following advantages:

zincreased power quality

The UPS has its own internal voltage and frequency regulators which ensure that its output is maintained within close tolerances independent of voltage and frequency variations on the mains power lines.

zincreased noise rejection

By rectifying the input AC power to DC power, and then converting it back to AC power, any electrical noise present on the input mains supply line is effectively isolated from the UPS output, therefore the critical load sees only clean power.

zpower blackout protection

If the mains power fails, the UPS continues to power the critical load from its battery source, leaving the load immune from power disturbances.

1.2 Design Concept

1.2.1 HIPULSE U Module Design

This section describes the operating principle of an individual module. The UPS basically operates as an AC-DC-AC converter (see Figure 1-1). The first conversion stage (from AC to DC) uses a 3-phase, fully controlled silicon-controlled resistor (SCR) bridge rectifier to convert the incoming mains supply into a regulated DC busbar.

Bypass AC
supply
Rectifier	Inverter	Static switch
Rectifier		UPS AC
AC supply		output

Battery

Figure 1-1 Single module block diagram

The DC busbar produced by the rectifier provides both battery charging power – being equipped with a temperature compensated battery charging system, to prolong battery life – and power to the inverter section – which utilizes the latest integrated gate bipolar transistor (IGBT) switching space vector pulse width modulation (SVPWM) design – and provides the second conversion phase, that is, reconverting the DC busbar voltage back into an AC voltage waveform.

During normal operation, both the rectifier and inverter sections are active and provide regulated load power whilst simultaneously charging the battery. In the event of a mains power failure, the rectifier becomes inoperative and the inverter is powered solely from the battery. Critical load power is maintained under these conditions until the battery is fully discharged, whereupon the UPS shuts down. The end of battery discharge is assumed when the battery voltage falls below a preset value (that is, 330Vdc for a 400Vac system).

The period for which the load can be maintained following a mains power failure is known as the system’s “Autonomy Time” and is dependent upon both the battery A/Hr capacity and the applied percentage load.

HIPULSE U UPS Single Module And “1+N” (Expandable) 160/200/300/400kVA User Manual