Model Predictive Control of a 9- Level Packed U-Cells based Grid-Connected PV System

In this paper, a high-reliability photovoltaic (PV) system based on a 9-level Packed U-Cells (PUC9) inverter is investigated. The PUC9 inverter is a cost-effective topology, which requires less components to generate nine voltage levels than traditional Multilevel Inverter (MLI) topologies. The main goal of the proposed system is to inject PV power into the grid with high efficiency and high-power quality (unity power factor and low THD). A Finite-set Model Predictive Control (FS-MPC) approach is designed to control the injected grid current while balancing the capacitors' voltages. A current oriented incremental conductance (IncCon) based Maximum Power Point Tracking (MPPT) algorithm is implemented to extract the maximum PV power. The simulation results are presented to prove the high capability of the proposed controller in balancing the capacitors' voltages and injecting grid current with high power quality.