This paper presents an extension of the dual-layer model predictive control (MPC) for industrial DC microgrids. This structure allows an easier integration of stochastic methods on all levels. Moreover, in the new three-layer MPC, energy storages are proposed for each level. As a proof of concept, a control is presented for the new layer, the primary control level in microgrids. The MPC as a central control strategy, has the disadvantage that a new model has to be created for new bus participants. By a simply expandable state space model and a parameterization with data sheet values, this disadvantage can be refuted. Further, for the application on a programmable logic controller (PLC), a simpler and faster MPC with an equal control performance, is presented.