Design and Implementation of 1kva Uninterrupted Power Supply

The power conditioner designed to deliver an output of 1.0KVA basically it’s composed of a battery control circuit, the inverter and automatic voltage regulator. The inverter stage is the part that will take power from the battery and by means of switching circuits inverts the d.c to a.c and steps up from 12V to 220V at the output. The automatic voltage regulator is the part whose function is to regulate the output from the inverter and mains to the load (i.e. 220V). The third stage is the control circuit, this uses a relay to sense when there is power or not, for economic reasons the same transformer used for inversion and battery charging. When there is power the relay switches such that the transformer is in step down mode and by means of full wave diode rectification supplies d.c to charge the battery. And when there is loss of power, the relay sense loss of power and switches to inversion mode and in this mode the transformer serves as a step up i.e. stepping 12V from battery to 220V. The output of transformer was equipped with several taps, which by means of a control circuit connected to several relays that selects which of the tap is best approximated to 220V at the output.