Due to the rapid decline of fossil resources and the impact of their use for electric power generation on the environment, renewable energy sources are increasingly explored and integrated into the power grid. Among the Renewable energy sources, photovoltaic (PV) systems are one of the most integrated into the utility grid. Thus, this paper presents a control scheme based on instantaneous power theory (IPT)and model predictive control (MPC) to inject the PV power into the grid at unity power factor with minimum current harmonics. The proposed control strategy is applied to a two-stage grid connected PV system which employs boost converter and two-level voltage source inverter. The current references are obtained in the dq reference frame based on IPT. A finite control set model predictive control (FCS-MPC) is used to control the inverter current in order to inject with high accuracy the current references into the grid. The effectiveness and the performance of the proposed control strategy is confirmed by MATLAB/Simulink under various solar irradiance level.