In this paper, a primary Model-based Predictive Control (MPC) for Distributed Energy Resources (DERs) is studied. This primary control regulates voltage and frequency, and has the capacity to set a predefined operation point while simultaneously imposing security constraints on the inverter's output current. To achieve these objectives, the MPC takes into account the LCL filter dynamics to increase the prediction accuracy of the system. The MPC algorithm is formulated as a Quadratic Programming (QP) problem which is solved using a first-order optimization method. To validate this approach, simulation results using MATLAB/SIMULINK and PLECS are presented. The results confirm the efficacy of the proposed primary control method.