Direct Model-Based Predictive Control of a Three-Phase Grid Connected VSI for Photovoltaic Power Evacuation

This paper presents a direct model predictive method for controlling the grid current of a three-phase photovoltaic system. The model of the inverter with an LCL filter in synchronous reference frame is presented in state-space format. The model predictive control scheme uses a compact cost function for simultaneously controlling the injected grid current, maintaining the capacitor dc-link voltage constant, and minimizing the switching frequency. Also, the reference signals for the control loop are generated in the predictive algorithm rather than through the use of cascaded PI controllers. Results for the proposed control scheme are presented.