Cooperative Model Predictive Control Scheme for Dispersed Smart Inverters at the Grid Edge

Growing number of distributed energy resources (DERs) requires cutting-edge control schemes to ensure uniform but not identical involvement of DERs to address fluctuations on voltage of the grid cluster. Designing such control schemes for grid clusters with high penetration of DERs is complex and depends on physical configuration of the clusters themselves. This paper proposes a two-layered cooperative model predictive control framework for fleet of dispersed smart inverters connected to a three-phase cluster located at the edge of the grid. The upper layer of the control framework ensures cooperative operation of fleet of smart inverters to perform voltage regulation and address voltage fluctuations across the grid cluster; while the lower level controller guarantees each individual inverter obeys the dictated references for active/reactive powers by the upper layer controller. In addition, the proposed two-layered controller has low voltage ride through (LVRT) capability to support the grid cluster during voltage sags. By employing the proposed control framework, the smart inverters will inject desired active/reactive powers based on the actual condition of the entire cluster. The control scheme is verified by simulation.