GRID-CONNECTED PHOTOVOLTAIC SYSTEMS WITH MULTILEVEL CONVERTERS – MODELING AND ANALYSIS

Abstract

In this paper, a comparison between three double-stage grid-connection systems in central inverter configuration is presented. This configuration can be used to obtain a wide power range and is suitable for the connection to three-phase grids. In this case, the photovoltaic (PV) panels are connected to the inverter via a dc-dc converter to ensure an optimal dc voltage level. The focus is on the characteristics and properties of the used converter’s structures. All the design steps of a grid connection system are also presented. Both two-level (2L) and three-level (3L) voltage structures are implemented. At the end of the paper, a detailed analysis highlights the advantages and disadvantages of the three photovoltaic systems connected to the grid.