Microgrid system advanced control in islanded and grid connected mode

This paper presents an advanced controller for the Microgrid system which can operate in grid connected mode and Islanded mode. The presented controller is designed such that it can be used by each Distributed Generation (DG) systems in the Microgrid. Two control schemes algorithms are presented firstly inner current and voltage control loop are proposed for controlling output of three phase grid interfacing inverter and secondly external real and reactive power control loops which incorporates the droop controller for controlling real and reactive power output and facilitating robust and accurate power sharing between DGs once the Microgrid is Islanded due to some utility grid faults. The controller is able to switch between different operating transitions modes for example from Islanded to Grid connected mode after proper resynchronization without affecting the critical loads. The performances of presented controller have been verified in the Matlab/Simulink simulation.