Two-level control for improving the performance of MicroGrid in islanded mode

In this paper, a two-level coordinating control approach is developed for the islanded operation of a microgrid system. The microgrid includes n parallel connections of distributed generation (DG) units. These units and the load are connected to the common coupling point (PCC). In the islanded operation of the microgrid, the master DG unit handles the voltage and frequency control of the load, and the slaves DG units regulate their power components based on utilizing the conventional dq-current control strategy. It is shown that the parallel connection of n DG units in islanded mode forms an interconnected control system which is conveniently controlled in a two-level coordinating scheme. MATLAB simulations of a typical microgrid system have illustrated the effective performance under the developed control strategy.