Modeling and control of a three-phase isolated grid-connected converter fed by a photovoltaic array

This paper shows the modeling and control design of an isolated two-stage three-phase grid-connected converter for photovoltaic (PV) applications. The converter stages are modeled in order to obtain small-signal transfer functions that are used to design PI compensators. Three controllers are used in the system: one for the output voltage of the PV array, one for the DC link capacitor and another for the sinusoidal three-phase output currents. Simulation results are presented and they show that the compensators are correctly designed and may be employed in practical systems.