PERFORMANCE INVESTIGATION OF GRID CONNECTED QUASI-Z-SOURCE 1NVERTER FOR PHOTOVOLTAIC SYSTEM

Abstract

Renewable energy technologies are gaining popularity in this world with exponential increase of demand of electricity for various activities, so are the technologies to integrate them in existing electricity grids. Among various popular renewable energy sources, Solar Energy is the most economical and fastest growing energy sources. One of the major challenges is to accommodate renewable energy in the existing grid which in many cases is many decades old. Also cost reduction of Inverter is necessary along with improved reliability and seamless grid integration. This report presents an overview of the existing inverter and other power electronic technologies which are used in Solar-power Conversion System and their limitations along with Quasi-ZSource Inverter (qZSI) technology, which overcomes the limitation of conventional inverter and Z-Source inverter. Various PWM techniques to incorporate boost factor and reduce leakage current along with several control strategies to feed the Solar-power to grid have been discussed. Simulation for various PWM techniques to incorporate shoot-through in qZSI has been presented and also several results have been compared with the result of simple ZSI to prove its supremacy over simple ZSI. Hysteresis-control and P1-control strategies have been compared while feeding power from solar panel to grid through qZSI. SVPWM and OEPWM technique has been compared to demonstrate the reduction of leakage current from Solar (PV)-panel in case of OEPWM. In each case Perturb & Observe MPPT algorithm has also been used to extract maximum power from solar-panels. A prototype of qZS1 has been developed to validate the simulation results, which has been reported at the end.