Supervisory Control of a Hybrid AC/DC Micro-Grid with Load Shedding Based on the Bankruptcy Problem

In this paper, a supervisory controller is proposed to manage the power flow in a hybrid AC/DC micro-grid for both grid-connected and disconnected modes. When the hybrid AC/DC micro-grid is connected to the utility grid, power surplus or shortage leads to power trade between the micro-grid and the utility grid. In the grid-disconnected mode, the renewable power sources (wind and solar generation subsystems) are responsible of supplying the power demanded by the loads by themselves. In this case, the loads are classified as critical and non-critical loads, where critical loads are those that should be supplied in any condition. When the maximum available power is smaller than the power demanded by the critical loads, the battery banks are set in the discharging mode to satisfy the demand. Otherwise, the non-critical loads are supplied according to the proposed load shedding scheme, which is developed based on the bankruptcy problem. In summary, this paper proposes a new supervisory controller for a hybrid AC/DC micro-grid, as well as a new load shedding scheme to supply the non-critical load in grid-disconnected mode. The effectiveness of the proposed supervisor controller is evaluated through simulation.