Design and construction of single phase pure sine wave inverter for photovoltaic application

This paper discusses the design and construction scheme of an inverter system which converts the DC voltage collected from a photovoltaic (PV) array into AC voltage. The output is a pure sine wave, with the voltage and frequency of the standard grid output. The system consists of a Switch Mode Power Supply (SMPS) and full bridge inverter circuit with a passive filter. The power supply supplies the DC voltage needed to activate the optocouplers, which are connected to the switches of the full bridge circuitry. The optocouplers work as an isolation for the full bridge circuit. High frequency Pulse Width Modulated (PWM) pulses are generated by a microcontroller (PIC18F4431) and provided to the switches of full bridge connection. The full bridge inverter outputs a PWM sine which is later conditioned to pure sine by an L-C filter. Finally, the output voltage and current is measured and displayed on an LCD (Liquid Crystal Diode) display.