MODELING AND CONTROL OF MULTI-LEVEL INVERTER FOR THREE-PHASE GRID-CONNECTED PHOTOVOLTAIC SOURCES

The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The proposed control scheme ensures the injection of the generated power in the distribution grid with fast dynamic response, while providing an additional active power filtering capability providing the required harmonic and reactive currents to be considered. The control scheme is validated by means of simulations with a cascade converter which interfaces to a distribution grid. Also, for DC link voltage control, it is needed that stabilizes the voltage at the inverter input to insure a continuous flow of energy exchange between the grid and the PV system. Also, a LC filter is necessary to filter the output current and voltage from the harmonics and to protect the grid from their destructive effect. Finally, this paper presents detailed modeling of the gridconnected photovoltaic generation system components, in Simulink/Matlab software. Simulation results presented to validate the components models and the chosen control schemes.