New Two-Layer Power Control Scheme in Islanded Cyber-Physical Microgrids

Abstract

Power microgrids are developing as complex cyber-physical systems. In this paper, a novel two-layer power control scheme is proposed to coordinate distributed energy resources (DERs), e.g., photovoltaics (PVs), energy storage system (ESSs), and loads, for both the short-term and long-term power imbalance in islanded alternating current (AC) microgrids. The first-layer control is based on local measurement and realized by model-predictive control, which provides fast dynamic response and small steady-state error for power inverters. The master–slave control scheme is adopted to achieve autonomous power balancing of the microgrid. The second-layer control is performed by a consensus-based distributed control for coordination among DERs via cyber networks. The second-layer control operates for power management by charging/discharging ESSs, PV curtailment, and load shedding, when the local first-layer control cannot balance the power in the microgrid. With the proposed control scheme, the power balancing of islanded microgrids can be achieved autonomously by adjusting the power output of all DERs. The two-layer control scheme is implemented in an islanded cyber-physical microgrid and the simulation results validate the effectiveness of the proposed approach.