Design and Fabrication of a 1kVA Power Inverter

Inverters in residential and industrial environments supply backup power during utility grid outages. This study aims to design and construct a 1kVA, 220-volt inverter that operates at a frequency of 50Hz. The components and materials for constructing this device were sourced locally and met stringent standards. The operation of the inverter involves a simple conversion process where 12V DC from a battery is transformed into 220V AC. This is achieved using integrated circuits and semiconductors functioning at a 50Hz frequency, with the final conversion occurring through the windings of a transformer. The transformation stage is one of the four steps that the inverter goes through using a 1000VA transformer, next, the oscillator stage is realized with an SG3524 Pulse-Width Modulator (PWM) IC. The driver stage controls the switching and is implemented with MOSFET IRFP 250N. A feedback stage monitors the output voltage to ensure it does not fall below the IEEE recommended value of 2.5% of the nominal value. It included supervisory circuits for inversion mode, low battery detection, updated battery connections, etc. Indicators with LEDs were added to track the inverter. It was tested under load and in an open circuit. A rough estimate was made for both output power and efficiency. The inversion ran for 7.8 hours before shutting off with a connected 100W lightbulb as the load.