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1.3.- Operating principle.
The described UPS is an On-line double conversion equipment with automatic bypass according with the European standard
EN62040-3. This kind of UPS makes a double conversion of the input voltage in a continuous way and without any interruption.
As the loads are not connected directly to the mains there are not interferences transfer to them; also, the double conversion
guarantees a stabilized energy, both voltage and frequency, which is the ideal for the correct operation of the critical loads.
When the input voltage is out of the permissible range of the equipment or there is a black out, the load is fed from the energy stored
in the batteries.
The system is provided with an automatic bypass; in case of UPS fault or overload, the bypass connects the critical loads to the
bypass mains directly, which allows to restore the normal operating conditions of power supply without any interruption. See figure
1.3.1.
1.3.1.- UPS block diagram.
BYPASS MANUAL / MANUAL
BYPASS
BYPASS MANUAL / MANUAL
BYPASS
LINEA BYPASS / BYPASS LINE
LINEA BYPASS
BYPASS LINE
ENTRADA RED
MAINS INPUT
RECTIFICADOR - CONVERTIDOR STEP
UP RECTIFIER - STEP UP CONVERTER
INVERSOR
INVERTER
INTERRUP TOR ESTÀTICO
STATIC SWITCH
SALIDA - CARGA
OUTPUT - LOAD
CARGADOR DE
BATERÍAS
BATTERY CHARGER
ARMARIO DE BATERÍAS
BATTERY CABINET
1.3.2.- Input, power module and output.
From the input terminals, the mains is connected through the MAINS INPUT I1 switch to the power module.
During a mains failure or it is out of the permissible UPS range, the step-up rectifier module, makes the DC/DC conversion from the
battery and in case of restoring it makes the AC/DC conversion from the mains (normal operation).
After, the direct current supplies the inverter module, which is in charge of inverting the DC to alternating current making it suitable
for the load requirements.
The last module is the automatic bypass; it connects, in normal operation, the filtered and regenerated energy from the inverter
module to the loads. In case of UPS fault or overload, the UPS output will transfer to the bypass line; in this situation, the mains
is in charge of feeding the loads. Once the fault, which has provoked the transference to bypass, is solved, the static switch
transfers back the load to the inverter automatically.
Through the UPS OUTPUT SWITCH I4, the loads are supplied in a filtered, regenerated and stabilized way. See diagram 1.3.1.