High gain DC/DC converter for the grid integration of large-scale PV systems

The global trend towards larger size ground mounted photovoltaic (PV) power plants seems set to continue, with the development of several projects in the 100MW range and higher. This installation trend will challenge the existent PV plant architectures by requiring power converters with a higher power rating and a higher voltage level at the point of common coupling (PCC), which can lead to higher ratio transformers or more transformation stages to be used for the connection with the electricity grid. This paper proposes a solution to minimize the number of transformation stages or the transformer turns ratio of a grid-connected PV plant without changing the standard configuration of the system. The paper introduces a multistring PV system architecture based on a high voltage gain DC/DC converter. A 1MW section of a PV plant has been modeled and simulated using MATLAB/Simulink and PLECS Block-set. The simulation results of three different case studies are presented to evaluate the performance of the proposed PV system configuration.