A cost minimization strategy for the control of hybrid AC-DC microgrids in industrial systems

This paper deals with the very short time predictive control of a hybrid microgrid (μG). The hybrid μG is characterized by the presence of two sections operating in alternating current (AC) and in direct current (DC), respectively. The proposed very short time predictive control is based on an optimal strategy focused on the coordination of loads and energy resources and aimed at minimizing the cost sustained for the imported electrical energy as well as the costs required by dispatchable generators. In order to face with some challenges involved in modern power systems, different energy resources are considered such as storage systems, dispatchable and non-dispatchable generators. The control procedure is formulated as a non-linear optimization problem aimed at minimizing the above costs while satisfying constraints related to a correct operation of the μG and an optimal management of the devices installed in the μG (e.g. the bus voltage magnitude has to fall into admissible ranges, the stored energy cannot exceed the battery size and so on). With reference to a hybrid μG, which is obtained by a modification of the distribution system of an actual industrial facility, a case study was investigated in order to show the feasibility and the effectiveness of the proposed control strategy.