Stand-alone DC Microgrids for Rural Areas: A Decentralized Energy Management and Voltage Regulation Approach

Electrifying remote rural areas through the extension of main grid transmission lines is often impractical due to prohibitive costs. So, stand-alone microgrids offer a more viable solution, particularly when powered by renewable energy sources like solar and wind, which are almost freely accessible and environmentally friendly. This paper explores the implementation of DC microgrids (DC-MGs) for such off-grid communities. DC-MGs are favored as they efficiently integrate diverse renewable generation units with DC outputs. Concerning the intermittent nature of renewable resources and the almost unpredictable demand profile in islanded microgrids, a combination of energy storage systems and generation units is typically used to ensure a continuous energy supply. However, this paper deploys the electric spring - a smart demand-side management technique - as an alternative to typical storage banks, aiming to improve the flexibility of DC-MGs in managing the common bus voltage amid uncertainties. An adaptive droop control strategy is used to ensure precise power-sharing among energy units and achieve effective voltage regulation even under high-load conditions, while accounting for line impedances. The performance of the proposed approach has been evaluated via different simulations using MATLAB®/Simulink software.