Scalable DC Microgrids for Rural Electrification in Emerging Regions

Abstract

We present the design and experimental validation of a scalable DC microgrid for rural electrification in emerging regions. A salient property of the DC microgrid architecture is the distributed control of the grid voltage, which enables both instantaneous power sharing and a metric for determining the available grid power. A droop-voltage power-sharing scheme is implemented wherein the bus-voltage droops in response to lowsupply/high-demand. Additionally, the architecture of the DC microgrid aims to minimize the losses associated with stored energy by distributing storage to individual households. In this way, the number of conversion steps and line losses are reduced. We calculate that the levelized cost of electricity (LCOE) of the proposed DC microgrid over a 15 year time horizon is $0.35 per kW-hr. We also present experimental results from a scaleddown experimental prototype that demonstrate the steady state behavior, the perturbation response, and the overall efficiency of the system. Moreover, we present fault mitigation strategies for various faults that can be expected to occur in a microgrid distribution system. The experimental results demonstrate the suitability of the presented DC microgrid architecture as a technically advantageous and cost effective method for electrifying emerging regions.

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

“…A value of V B higher than V ref indicates that number of power supplying nanogrids in the cluster is more than number of power demanding nanogrids, therefore, i th nanogrid needs to absorb power to keep the microgrid stable. The coordinated power absorption in this condition is achieved through an adaptive I-V droop control given by (8) and shown in Fig.2c (Mode 5). Rather than having a fixed value of droop resistance, a charging droop coefficient K c has been defined as a function of droop resistance R d and SOC i given by (9).…”

“…PV/battery-based DC microgrids have gain more popularity due to a) natural availability of solar energy in most of under-developed areas (most regions in Southeast Asia and Africa receive abundant sunlight i.e. above 5.5 kWhr/m 2 /day), b) higher efficiency of DC distribution in comparison to AC distribution c) wide market availability and large penetration of highly efficient DC loads, d) gradually decreasing prices of PV panels and batteries, and e) omission of redundant AC/DC interconversion stages from generation to utilization [2,[5][6][7][8].…”

“…Wardah et al [15] presented a partially distributed architecture, in which peer to peer electricity sharing was enabled by GSM based through power management units (PMU's). Similarly, Madduri et al [16,17] proposed a PV/battery-based central generation and distributed storage architecture, with the provision of local batteries in individual households. The advantages of distributed architectures are mainly reduction in distribution losses and modularity in structure.…”

Islanded DC Microgrid Architecture with Dual Active Bridge Converter‐Based Power Management Units and Time Slot‐Based Control Interface

“…In Ref. , a scalable architecture of DC microgrids with a droop‐voltage power‐sharing scheme is reported where system losses are minimized by distributing stored energy to individual loads (households). The power conversion circuit is a basic DC/DC buck converter operated by peak current control algorithm.…”

A Distributed Event-Triggered Control Strategy for DC Microgrids Based on Publish-Subscribe Model Over Industrial Wireless Sensor Networks

“…I N the future modern smart grids, a direct current (DC) microgrid is becoming a natural substitution for the traditional power grid, mainly due to the ease of integration of the RESs. The DC microgrids have found the ever-increasing importance for the efficient realization of a number of crucial applications in the electric power industry, as they differentiate themselves from the AC grid counterparts in having the non-zero-crossing current and reactive power [1]- [3]. However, controlling of the DC microgrid subsystems poses a considerable challenge, e.g., grid voltage stabilization is still a major problem due to Manuscript the limitations in the voltage compensation techniques, when compared to the conventional AC power system [4]- [6].…”