System Description - AEG Protect D Series User Manual

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2.2 System description

The UPS is connected between the public utility's mains and the loads to
be Protected.
The power section of the rectifier converts the mains voltage to DC voltage
for supplying the inverter. The circuit technology used (PFC) enables
sinusoidal current consumption and therefore operation with little system
disturbance. The charger is buck topology from DC bus.
The configuration of this charging REC means the harmonic content of the
charging current for the battery is almost zero, so the service life of the
battery is increased even more. The inverter is responsible for converting
the DC voltage into a sinusoidal output voltage. A microprocessor-
controlled control system based on pulse-width modulation (PWM) in
conjunction with digital signal processor technology and extremely quickly
pulsating IGBT power semiconductors of the inverter guarantee that the
voltage system on the Protected busbar is of the highest quality and
availability.
In the event of mains faults (e.g. current failures), the voltage continues to
be supplied from the inverter to the load without any interruption. From
this point onwards, the inverter draws its power from the battery instead