A Distributed Approach for Secondary and Tertiary Layer Control in DC Microgrids

Localized droop control has been established to be a preferable approach for realizing primary layer control for ac and dc microgrids. On the other hand, centralized control for secondary and primary layers is used to maintain the balance between energy supply and demand to keep microgrids in a stable operating window for the primary layer. However, ensuring reliable and real-time communications for centralized control systems in normal and critical scenarios (disasters) can be challenging. In addition, energy systems deployed for remote and rural electrification often face the issue of intermittent connectivity due to geographical and infrastructure constraints. This paper presents a distributed approach for realizing secondary and tertiary control layers called SOLEEN (self-organizing local electrical energy networks). It addresses the challenges of unreliable and non real-time central communication and computing systems often used in microgrid control. SOLEEN ensures grid stability in the absence of central control layer failure through a scalable distributed framework based on self-organizing principles. It also allows for easy integration of other layers of control. Operating principles, simulation, and experimental results are presented in the paper.