DESIGN AND FABRICATION OF A 3.5KVA INVERTER

The main purpose of the project was to design and construct a 3.5KVAinverter whichmakes use of both Solar and mains or grid supply for charging the batteries. This is toreduce the frequency of power outages experienced in our homes and businesses. The project was carried out with the use of two 12V batteries connected in series togivea total of 24V DC which would serve as input for the inverter when on inverting modeand give an output of 220V AC for household appliances. Incorporated withintheinverter was load control features, such that when the inverter stops charging andstartsinverting, at a particular battery level set by the user, the heavy loads would be cut off while supply of power to the light loads continues. But when critical battery level isreached the light loads are also cut off and the inverter shuts down. This was done usingMicrocontroller in controlling relays which either powers on the load or cuts off theload when the battery is low. The proposed inverter design has two outputs throughwhich load management was achieved. One of the outputs is designated to light loadsand the other to heavy loads. The Microcontroller controls the load stage which canbeprogrammed through the keypad to monitor the output power to the loads in output oneand two, to ensure they do not draw power beyond the limits programmed by the user. To achieve this, the Microcontroller cuts off either of the outputs which exceed the set limit. With the help of a timer controller and by means of the keypad a particular loadpower duration can be programmed so that the output can be shut down at the end of theset time. This timer control and load power control are ways the user can control power consumption and help in power management