Conversor modular multiniveis para usinas solares fotovoltaicas: topologia e controle

Abstract

Focused on photovoltaic power generation from large scale plants, with installed capacity greater than 1 MW, this work reveals the inability of conventional converters in handling with irregular environmental conditions on large panels associations, in the case of partial shading by clouds, for example. Although high-efficiency on energy conversion inherent from the commonly used topology, the losses caused by large arrays and, consequently, lower number of maximum power point trackers impact energy generated by the power plant. In this work, an alternative solution to conventional central inverters is presented, in order to combine the multiple continuous current inputs from each inverter and, thereby, to reduce the size of the panels arrangements. Independent panels blocks are subjected to different irradiation conditions and temperature and therefore they provide different power levels to each level of the proposed converter. The power injection into the grid, however, must take place in a balanced way. The main difference between this implementation and also the main focus of this work are in control of a multilevel converter for generating unbalanced power per level, while the power injection request the grid is balanced. Due to this reasons this work seeks to present ways to balance the converter generation through the neutral displacement.