Design and Development of Micro Off-grid Inverter for Solar Photovoltaic System using Proteus Simulation

Abstract

Solar photovoltaic panel generates DC power. It needs to be converted to AC power since most electrical appliances used in our day to day life runs on AC power supply. The conversion of DC to AC power happens using an inverter comprising of multiple electronic components, which generates harmonics in the AC power systems. The present investigation is focused to design a micro off-grid solar inverter with a minimal number of components using Proteus design suite simulation to generate quality power at an optimum cost. The designed solar inverter circuit mainly consists of resistors, capacitors, voltage regulators, CD 4047 IC, OP07 IC, R-C Circuit, MOSFETs and step-up transformer. The output of CD 4047 IC was given to the R-C three stage circuits for conversion from square to sinusoidal wave through amplifiers OP07 to boost the waveform voltage from 3.5 V to 7.0 V. The amplified sinusoidal waveform signal was applied to the gate of MOSFET combinations. Each set consists of two MOSFETs connected in parallel to produce voltage with 180° out of phase waveforms at MOSFET drain terminal and then supplied to center tapped step-up-transformer to produce constant 230 V AC output voltage at 50 Hz. The voltage regulation was achieved with the help of a DC-DC Boost Converter which makes the system capable of giving reliable power at 230 V even for varying solar irradiation from 145 W/m² and above. Frequency regulation was achieved by varying the values of R and C across pins 1, 2 and 3 of CD 4047 IC. The maximum efficiency of the developed micro off-grid solar inverter’s hardware circuit was found to be 93.49% based on experimental measurements and 95.72% based on the simulation studies.