A dsPIC based efficient single-stage grid-connected photovoltaic system

Abstract

Compared to multistage, single-stage grid-connected photovoltaic system (GCPVS) has advantages such as topological simplicity, smaller size, high efficiency, etc. However, complexity in monitoring and controlling scheme is much increased as functions such as maximum power-point tracking (MPPT), synchronization and load sharing with the grid, etc. need to be considered simultaneously in same stage. A high performance dsPIC based single-stage GCPVS performing aforementioned functions simultaneously by adjustment of inverter output voltage phasor with respect to the grid voltage, is presented. Only AC quantities (inverter output voltage and current, grid voltage) sensing and monitoring are required in the proposed system. The proposed system poses advantages over existing single-stage systems such as more topological simplicity, less system components, better performance, reduced size and weight, etc. Variations of both photovoltaic (PV) generation and grid voltage are considered in load sharing in the proposed system. Simulation results validate acceptability of the system.