Cascaded Predictive Direct Power Control for Grid Connected Photovoltaic System

Generally, the topology of a grid connected photovoltaic system (PV-GCS) includes two or more power converters placed in cascade and they are separately controlled requiring several controllers. In this paper, an optimal cascaded predictive power control strategy (CPPC) for PV-GCS is presented. The method considers the three cascaded power converters (Buck converter, Boost converter and a three phase Voltage Source Inverter (VSI) as one stage system and controls them at the same time with the same optimized cost function, providing more flexibility and simple controllability and allows the system able to compensate the undesired grid reactive power. Also, the functioning at the maximum power point (MPP) is ensured by the same control method. The presented research is validated by detailed simulation and experimental tests, which confirm the suitability of the proposed method for PV-GCSs.