MPC-Based Microgrid Control With Supplementary Fault Current Limitation and Smooth Transition Mechanisms

This study presents a control strategy for a microgrid that consists of multiple distributed generators (DGs), for both grid-connected and islanded modes of operation, where every DG is interfaced to the main grid via a voltage sourced inverter (VSI). finite control set model predictive control (FCS-MPC) is used as the primary controller to regulate the output power of each DG (in the grid-connected mode) or the voltage of the point of DG coupling (in the islanded mode of operation). In the grid-connected mode, direct power model predictive control (DPMPC) is implemented to manage the power flow between each DG and the main grid. In the islanded mode, voltage model predictive control (VMPC), as the primary control, and droop control, as the secondary control, are employed to control the output voltage of each DG and system frequency. The controller is equipped with a supplementary current limiting technique to limit the output current of each DG in case of overcurrent scenarios. The control approach also enables a smooth transition between the two modes. The performance of the control strategy is investigated and verified using PSCAD/EMTDC software platform.