Comparative study between two and three-level topologies of grid connected photovoltaic converters

The main objective of this paper is to achieve a comparative study between two and three-level converters used in transformerless grid connected two-stage photovoltaic systems. For this purpose, a numerical model of the conversion system has been implemented in Matlab/Simulink software. It consists of a PV array feeding a DC/DC converter as well as a three-phase voltage source converter that ensures the power transfer to the grid through a line inductor. The simulation results showed that the three-level voltage source converter has better performance than the two-level topology in terms of line current harmonic distortion (THD) as well as the line inductor's volume.