A Decentralized Control Architecture Applied to DC Nanogrid Clusters for Rural Electrification in Developing Regions

Abstract

DC microgrids built through bottom-up approach are becoming popular for swarm electrification due to their scalability and resource sharing capabilities. However, they typically require sophisticated control techniques involving communication among the distributed resources for stable and coordinated operation. In this work, we present a communication-less strategy for the decentralized control of a PV/battery-based highly distributed DC microgrid. The architecture consists of clusters of nanogrids (households), where each nanogrid can work independently along with provisions of sharing resources with the community. An adaptive I-V droop method is used which relies on local measurements of SOC and DC bus voltage for the coordinated power sharing among the contributing nanogrids. PV generation capability of individual nanogrids is synchronized with the grid stability conditions through a local controller which may shift its modes of operation between maximum power point tracking mode and current control mode. The distributed architecture with the proposed decentralized control scheme enables a) scalability and modularity in the structure, b) higher distribution efficiency, and c) communication-less, yet coordinated resource sharing. The efficacy of the proposed control scheme is validated for various possible power sharing scenarios using simulations on MATLAB/Simulink and hardware in loop facilities at microgrid laboratory in Aalborg University.

Optimal power dispatch in solar‐assisted uninterruptible power supply systems

“…The minimization of the grid utilization can be explained further through Figure 6, which shows the power taken by the battery to get charged through solar power (S b ) at any time t. Figure 6 shows that the power is taken from solar to charge the battery in "optimized case" is significantly higher compared with base case 2, as an intentional disconnection form grid is not inherently available. This trend can be seen during the peak time of solar power, ie, from an hour (10)(11)(12)(13)(14), where solar utilization by the battery can be seen at its summit in optimized case. To further elaborate on the dynamics of battery charging from solar, the graph for variations in SOC of the battery is shown in Figure 7.…”

“…The proposed solar integration scheme allows higher utilization of the solar resource, and therefore, the power demand from the grid is the lowest in the optimized case. This trend is visible during the sunlight hours (8)(9)(10)(11)(12)(13)(14)(15)(16) as the optimized methodology allows optimal sharing of the power from solar, battery, and grid to provide for the load, satisfying the main objective of the system that is the minimization of the total costs depend on the units purchased from the grid.…”

“…in home-based DC distribution, 8 solar PV intake, 9 and perceptiveness towards rural electrification has proved to be a transformative step in the future of solar PV. [10][11][12][13][14][15][16] Developed countries around the world have incentivized domestic solar installation through favorable policies such as attractive solar feed-in-tariff (FiT), 17,18 green certifications, and tax credits. to lower their energy dependence on fossil fuels and to promote solar energy, [19][20][21] encouraging domestic consumers to invest in roof top PV electricity generation with bidirectional energy transactions with utility grids.…”

Efficiency Comparison of AC and DC Distribution Networks for Modern Residential Localities

“…The shifting trend towards LED lights, electronics, mobile phone and laptop chargers in the modern home adds to the DC side, strengthening it further as compared to AC [8]. Moreover, lower line losses, lower voltage dips and simplified control associated with the low voltage DC distribution (LVDC) systems have made it an optimal choice for low-cost rural electrification [9][10][11][12][13][14]. Figure 1 depicts the penetration of DC in the power system.…”

A Modified Control Scheme for Power Management in an AC Microgrid with Integration of Multiple Nanogrids

“…It must have at least a single load and often has an energy storage associated to it. A cluster of these nanogrids are interconnected to form a microgrid [1][2][3]. The microgrid can operate in grid connected mode or in islanded mode/stand-alone mode.…”