Power injection system for photovoltaic plants based on a multiconverter topology with DC-link capacitor voltage balancing

This paper presents the simulation of a new topology for the power injection system of a single-phase grid connected photovoltaic generation system that is based on the parallel association of two voltage source inverters: one is a 3 level neutral point clamped operated using a low switching frequency strategy and the other is a 2 level inverter which operates with a pulse width modulation based strategy. The aim of this topology is that multilevel inverter injects the power and the other inverter controls the current quality. The DC-link capacitor voltage balancing is solved by using the redundant states of the multilevel inverter. The proposal optimizes the system design, allowing high power injection, permitting reduction of system losses and an increase of the energy injected into the grid.