Aplicação de inversores de três e quatro níveis em sistemas fotovoltaicos.

Abstract

This thesis deals with topologies of three and four levels with DC - Link stapled applied to photovoltaic systems. One of the problems inherent in multi-level inverters with stapled bus is to have an imbalance of tensions in capacitors. In view of this problem is proposed solutions to balance the tensions. studies are presented for all three topologies proposed inverters and two systems composed of: photovoltaic panel, converter DC=DC and multilevel inverter. An inverter systems with three levels of type NPC, however, with new modulaçãoes and operations. And another drive system with four levels where a new topology is proposed with a reduced number of components. In addition, a vector modulation is proposed for the four-level inverter. For each system presents the dynamic model, PWM, control diagram, performance analysis based on the current THD, voltage and WTHD losses in key addition to thermal stress. They are presented in this paper, simulation results and experimental for all topologies. To validate the test system, the structure was assembled with a source which emulates a photovoltaic panel, a boost converter (responsible for the MPPT) and multnível inverter. We also used a digital signal processor for generating the control devices and ber optic signals to avoid interference.