10
2.2 System
Description
The UPS is connected between the public utility 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. A separate, second
rectifier (charging REC set up using switch mode power supply
technology) is responsible for charging or trickle-charging the
battery connected in the intermediate circuit. The configuration of
this charging REC means the harmonic content of the charging
current for the battery is almost zero, which increases the service
life of the battery even more. The inverter is responsible for
converting the DC voltage into a sinusoidal output voltage. A
microprocessor-driven control based on a pulse-width modulation
(PWM) guarantees, in conjunction with digital signal processor
technology and extremely fast pulsating IGBT power
semiconductors of the inverter, a voltage system of the highest
quality and availability on the secured busbar.
In the event of mains faults (such as 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 of the rectifier. Since no
switching operations are necessary, there is no interruption in the
supply to the load.
The automatic electronic bypass serves to increase the reliability
of the supply further, especially in the case of individual systems.
It switches the public mains directly through to the load without
any interruption, e.g. when there is an inverter malfunction. As a
result, the automatic bypass represents an extra passive
redundancy for the load.
An integrated, manually operated bypass unit ensures an
uninterrupted supply to the connected loads in the case of
maintenance and/or service work. The internal electronic part
(with the exception of the metal-clad manual bypass) can be
disconnected via the mains input miniature circuit breakers.
