Uninterruptable power  Supply

An uninterruptible  power supply  provides emergency power when  utility power  is not  available. It  maintains the supply  under  all conditions. A UPS is used to  provide good quality power to the load when power fails,  regulate the load  voltage  when supply  voltage  fluctuates provide constant voltage and constant frequency supply  to the load  suppress the voltage spikes and minimize the  radio frequency interferences and electromagnetic  interferences.

Here  the rectifier  is used  to convert AC into DC. By  using   the batter bank DC can  be stored  to supply continuous power  when main supply  fails.  Inverter is used  to convert DC into  AC. The DC is fed into inverter either from rectifier  when  main supply is ON  or from  battery bank when it is OFF a ripple free AC  can be  obtained by using  filter circuit.

 The general categories of UPS  systems  are on line , off line  and line  interactive.