Distributed Secondary Control of Inverter Based Microgrids: Bi-Directional Communications

Owing to the mass availability of renewable energy sources, such as photovoltaic panels and wind turbines, they can be widely integrated into microgrids through power electronic converters. However, a proper hierarchical control scheme is required to maintain the stability of these modern microgrids that do not have the inherent inertia and flexibility of legacy power grids. Even though droop control works to maintain the balance between generated and consumed power, it is not sufficient to effectively mitigate frequency deviations. Hence, designing a secondary control approach can address the microgrid control deficiency. A distributed secondary voltage and frequency control scheme based on distributed cooperative control of a multi-agent system is proposed in this paper. The proposed methodology eschews the call for a centralized controller and convoluted communication infrastructure, thus, lowering the computational effort and reducing the chance of single-point failure. An islanded microgrid test system under various scenarios is simulated in MATLAB/Simulink to validate the efficacy of the proposed controller.