Coordinated control of MT and ESS in an islanded AC/DC hybrid microgrid

Abstract

In the AC/DC hybrid microgrid system under the island mode, the coordinated control of the main power supply and other distributed power sources is the key issue to ensure the stable operation of the microgrid. To solve this problem, a coordinated control method based on the main power supply and other distributed generators (DGs) is designed in this paper. Firstly, an AC/DC hybrid microgrid model with PV, PMSG, an energy storage system (ESS) and micro gas turbine (MT) is established; according to the characteristics of the different DGs, the control strategies, such as MPPT control and PQ control, are adopted. Secondly, the application of virtual synchronous generator (VSG) control in the MT and ESS is studied. A seamless switching strategy for the MT and ESS is proposed in view of the potential power outage when the MT is out of operation. In addition, the phase angle seamless switching method and a switching time sequence are designed. Finally, verification of the simulation is carried out using Matlab/Simulink. The simulation results show that the proposed coordinated control strategy ensures a small impact and short time during the switching process, which verifies the correctness and validity of the proposed coordinated control strategy.