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.