Control of three phase grid connected photovoltaic power systems

This paper proposes a control methodology for interfacing medium and large photovoltaic (PV) arrays to the power system distribution grid. First, the structure of the PV system in grid-connected mode is introduced. It consists of a PV array in addition to a power conditioning system for grid interfacing purposes. The power conditioning system is composed of a DC-DC boost converter, followed by a current controlled Voltage Source Inverter (VSI). The system was controlled to inject a clean sinusoidal current into the grid. Maximum power point tracking (MPPT) and PV cell modeling will be discussed as well. After that, simulation results of the system using MATLAB SIMULINK are presented. Finally, a case study was conducted to examine the effect of the interfacing transformer topology on the system during fault conditions.