DESIGN AND CONSTRUCTION OF A DUAL SOURCE 3.5KVA INVERTER SYSTEM

ABSTRACT

The aim of this project is to design a dual source 3.5KVA inverter at 50Hz and 220V using deep cycle batteries and dual sources of electrical energy (solar panels and utility mains). The circuit is made basically of: a transformer, a microcontroller, a relay, MOSFET array, and a feedback network. During operation, electrical energy from the solar panel is stored in the batteries and energy coming from the batteries are fed into the microcontroller (oscillator circuit), which is a pulse width modulating (PWM) integrated circuit comprising of a crystal oscillator and a comparator. These, together with the feedback network comprising the optocoupler and bridge rectifier, produce alternate pulse output. This is fed into the MOSFET array which amplifies the current sent to the transformer, the transformer steps up the voltage. The resulting alternating current output at 50Hz and 220V is then fed to the desired load. After construction and testing, the inverter was able to carry loads just under the specified 3.5KVA rating.