Liebert 1000kVA manual UPS Module, Battery Plant

Theory of Operation

Figure 6 UPS module block diagram

MULTI-MODULE UPS SYSTEM

				Control
				Wiring
	CONTROL POWER			To SCC
	Controls
Utility	Rectifier/			Output
Input		Inverter
				Power
	Charger
Power			Output
	Input			To SCC
	CB		CB

Battery

MBD

CB - Circuit Breaker

MBD - Module Battery Disconnect

SCC - System Control Cabinet

2.1.2UPS Module

The UPS module consists of module controls, a rectifier/charger, an inverter, protective devices and other accessories.

Module Controls: The module control logic monitors performance of the UPS module. The UPS module status is displayed locally and is also sent to the System Control Cabinet.

Rectifier/Charger: The rectifier/charger converts utility power from AC to DC to charge the battery and provide the DC input to the inverter. Its design limits reflected harmonic current distortion to source power and provides low-ripple DC power for charging batteries. Multiple rectifier/chargers can share a common battery plant, if that configuration is preferred for your application.

Inverter: The inverter converts DC power into the precise AC power required to supply a sensitive critical load. The inverter converts DC power into a pulse-width-modulated (PWM)/six-step waveform that is easily filtered into a clean sine wave output. The PWM/stepwave also minimizes the harmonic voltage distortion caused by typical switching power supplies and other non-linear load components used in computers and related electronics.

2.1.3Battery Plant

The battery is used as the alternate source of power to supply DC power to the inverter if the AC sup- ply voltage is outside the acceptable range. The battery supplies power to the inverter until the utility power is restored or until an alternate power source is available. If AC source power is not restored or an alternate power source is not available, the battery can be sized to provide power long enough for an orderly shutdown of the load.

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