Experimental tests on a multilevel converter for grid-connected photovoltaic systems

Abstract

A complete set of experimental tests on a novel conversion scheme for three-phase grid-connected photovoltaic (PV) generation systems is presented in this paper. The proposed scheme is based on two insulated strings of PV panels, each one feeding a standard two-level three-phase voltage source inverter (VSI). The inverters are connected to grid by a three-phase transformer with the open winding configuration on inverters side. The resulting conversion structure acts as a multilevel converter, doubling the power capability of a single VSI with given current rating. An original control method has been introduced to regulate the dc-link voltages of each VSI, allowing the whole converter to inject the PV energy into the grid and to perform as a power active filter.

Dual-inverter-based MPPT algorithm for grid-connected photovoltaic systems

“…In this paper, the dual VSI topology presented by the Authors in [11], [12] is considered, and a novel MPPT algorithm has been applied to maximize power injection into the grid, according to the block diagram of Fig. 1.…”