Central Inverter Topology Issues in Large-Scale Photovoltaic Power Plants: Shading and System Losses

Most of the large-scale PV power plants are based on central inverters, in which the PV panels are concentrated in single or few MPPTs and connected to the grid through three-phase inverters. Although its high conversion efficiency, extracting the total available power from an association of a large number of PV panels represents an issue in these systems. The irregular shading effects added to the intrinsic limitations in series/parallel panel associations may result in severe limits on the power injected into the grid. This paper is focused on simulations and experimental results from a power plant subjected to controlled shading conditions. In addition of this work, an alternative multi-MPPT converter topology capable of dealing with such conditions is enunciated and proper references from it are also pointed out.