Model predictive controller for grid-connected photovoltaic based on quasi-Z-source inverter

This paper presents model predictive controller (MPC) design for grid-connected Photovoltaic system using quasi-Z-source inverter (QZSI). The QZSI provides a cheaper, simpler, and one stage approach for PV arrays. Using traditional control for QZSI, the two sides (DC-side and AC-side) should be controlled separately. PI controller has been extensively used for QZSI but still PI has some limitations such as system nonlinearity. The main idea of MPC is based on the model of the QZSI and using this model, the future behavior of the output current is predicted over a period of time. Using a cost function, the predictions are assessed and the best switching state is selected to be applied. Using MPC, the output current is regulated based on the maximum PV available power. The QZSI inductor current and capacitor voltage are manipulated based on the same cost function. The simulation results using MATLAB simulink confirm the effectiveness of this controller and the advantages of the MPC as a simple and powerful method for power electronics converter as it does not need additional modulation techniques or internal control loops.