From DC nano- and microgrids towards the universal DC distribution system - a plea to think further into the future

The traditional ac power system is challenged by the increased amount of distributed energy resources. Enormous changes and investments are necessary in order to achieve an ac smart grid capable of coping with the challenges introduced. In dc, solutions seem to be more straightforward since most of the distributed energy sources and most of the...

PV architectures for DC microgrids using buck or boost exclusive microconverters

DC microgrids can connect directly dc renewable energy sources with increasing amount of dc loads. In this paper it is looked for possible architectures for integrating PV panels into dc microgrids, by means of microconverter strings. Three topologies are considered, featuring only buck microconverters and only boost microconverters, since they...

Characterization of Series Arcs in LVdc Microgrids

This paper provides an empirical study on series arc behavior in low voltage dc microgrids. The response of an R-L-C dc microgrid abstraction towards series arcs is studied experimentally for varying grid inductance, dc voltages, load capacitances and load currents. In order to account for the stochastic nature of arcs, experiments are...

Toward the Universal DC Distribution System

AbstractDue to an increasing number of power generation units and load devices operating with direct current (DC) at distribution level, there is a potential benefit of leading efforts toward building a DC distribution system. However, the implementation of DC distribution systems faces important challenges, including the market inertia of AC...

A State-Space Approach to Modelling DC Distribution Systems

Many modelling methods for the analysis of dc distribution grids only consider monopolar configurations and do not allow for mutual couplings to be taken into account. The modelling method presented in this paper aims to deal with both of these issues. A state-space approach was chosen for its flexibility and computational speed. The derived...

Stability and Decentralized Control of Plug-and-Play DC Distribution Grids

Changes in distribution grids pose significant challenges with respect to the control and management of these grids. Stability and decentralized control are vital to ensure the availability and accessibility of plug-and-play dc distribution grids that are (temporarily) without communication. Therefore, this paper presents guidelines for these...

Detection of series arcs using load side voltage drop for protection of low voltage DC Systems

Low voltage dc distribution grids face issues associated with arc faults, aggravated by the absence of current zero crossing. The focus of this paper is to comprehensively develop a method of series arc fault detection at the load side power electronics, based on the electrode dependent initial voltage drop occurring at the arc initiation....

Techno-economical Model based Optimal Sizing of PV-Battery Systems for Microgrids

Microgrid with integrated photo-voltaics (PV) and battery storage system (BSS) is a promising technology for future residential applications. Optimally sizing the PV system and BSS can maximise self-sufficiency, grid relief, and at the same time can be cost-effective by exploiting tariff incentives. To that end, this paper presents a...

Partially Rated Power Flow Control Converter Modeling for Low Voltage DC Grids

Scalable and robust low-voltage direct current (LVdc) distribution networks require solutions, allowing flexible power flow control and reliable short-circuit protection. In this paper, the continuous full-order large-and small-signal models of a partially rated power flow control converter (PFCC) are derived utilizing the generalized...

Quantifying the Benefits of a Solar Home System-Based DC Microgrid for Rural Electrification

Off-grid solar home systems (SHSs) currently constitute a major source of providing basic electricity needs in un(der)-electrified regions of the world, with around 73 million households having benefited from off-grid solar solutions by 2017. However, in and of itself, state-of-the-art SHSs can only provide electricity access with adequate...

The long road to universal electrification: A critical look at present pathways and challenges

Nearly 840 million people still lack access to electricity, while over a billion more have an unreliable electricity connection. In this article, the three different electrification pathways-grid extension, centralized microgrids, and standalone solar-based solutions, such as pico-solar and solar home systems (SHS)-are critically examined...

Power Flow Decoupling Controller for Triple Active Bridge Based on Fourier Decomposition of Transformer Currents

This paper proposes a power flows decoupling controller for the triple active bridge converter. The controller is based on a full-order continuous-time model of the TAB converter derived using the generalized average modelling (GAM) technique. GAM uses the Fourier series expansion to decompose the state-space variables into two components,...

An Adaptive Control Strategy for Dynamic Response of an Autonomous DC system

The dynamic behaviour - steady-state and transient - of the DC Microgrids during power disturbance can affect the system’s general performance. A hybrid combination of energy storage devices with slow frequency response, like a Fuel Cell, and with a fast dynamic response, like a Super-Capacitor, provides an improved dynamic response to stabilise...

A review of socio-technical barriers to Smart Microgrid development

Smart MicroGrids (SMGs) can be seen as a promising option when it comes to addressing the urgent need for sustainable transition in electric systems from the current fossil fuel-based centralised system to a low-carbon, renewable-based decentralised system. Unlike previous studies that were restricted to a limited number of actors and only took...

Low-Voltage dc System Building Blocks: Integrated Power Flow Control and Short Circuit Protection

Low-voltage direct current (LVdc) systems are a promising technology for systems with a high penetration of renewable sources and storage that operate with bidirectional power flow. In this article, a fundamental building block for LVdc is presented for different applications, such as charge controllers, voltage regulation in street-lighting...

An Adaptive Virtual Impedance Control for Reactive Power Sharing in Microgrids

In multi-inverter parallel connected islanded micro-grids, reactive power sharing is challenged by the differences in feeder impedance and various controller parameters. In order to address this issue, a virtual impedance reshaping strategy based on the consensus algorithm is proposed in this paper. The proposed method facilitates adaptive...

Virtual Impedance Control for Load Sharing and Bus Voltage Quality Improvement

This paper proposes a virtual impedance reshaping strategy to share active and harmonic power while promoting the PCC voltage quality. Moreover, the suggested method is resilient to cyber-attacks and immune to communication interruption and delay. Furthermore, it significantly reduces the communication burden. Experiments verify the...

A Resilience Enhanced Secondary Control for AC Micro-grids

Communication-based distributed secondary control is deemed necessary to restore the state of islanding AC microgrids to set points. As its limited global information, the microgrids become vulnerable to cyber-attacks, which by falsifying the communicating singles, like the angular frequency, can disturb the power dispatch in the microgrids...