A Comprehensive Control for Islanded Hybrid AC/DC Microgrid Involving Multi-terminal AC and DC Subgrids

Abstract

To realize the power dispatch in hybrid AC/DC microgrid involving multi-terminal AC and DC subgrids (HMG-MADS) and enhance the system inertia, a comprehensive control is proposed in this paper. Based on the principle of virtual synchronous generator (VSG) and virtual DC capacitor (VDC), the interrelationships of the bi-directional AC/DC converter (BAC) and bi-directional DC/DC converter (BDC) are analyzed. Then the demand of the virtual inertia is defined for BAC and BDC to enhance the system inertia while the reasonable power exchange law is determined for them to realize power support among the subgrids. Meanwhile, the AC subgrids voltage/frequency and DC subgrids voltage are well controlled by comprehensive control. With the defined demand of the virtual inertia and reasonable power exchange rule, a new P/V droop principle for BAC and a new P/V droop principle for BDC is established which can realize a proper assignment of subgrids supportive power and improve the system dynamic response. Finally, simulation results are demonstrated to show the effectiveness and feasibility of the comprehensive control algorithm.