Power electronics converters for an electric vehicle fast charging station with energy storage system and renewable energy sources

Fast Charging Stations (FCS) are a key element for the wide spreading of Electric Vehicles (EVs), by reducing the charging time to a range between 20 to 40 minutes. However, the integration of FCS causes some adverse impacts on the Power Grid (PG), namely the huge increase in the peak demand during short periods of time. This paper addresses the design of power electronics converters for an EV DC FCS with local storage capability and easy interface of renewables. In the proposed architecture, the energy storage capability is used to smooth the peak power demand and contributes to stabilize the PG. When integrated in a smart grid, the proposed architecture may even return some of the stored energy back to the PG. The accomplishment of the aforementioned objectives requires a set of different power electronics converters, described and discussed along the paper. In order to demonstrate the potentialities of the proposed EV DC FCS architecture, four different case studies were analysed.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work is financed by the ERDF – COMPETE 2020 Programme, and FCT within project SAICTPAC/0004/2015-POCI-01-0145-FEDER-016434 and FCT within project PTDC/EEI-EEE/28813/2017. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT agency. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency

Electric Vehicles Charging Stations’ Architectures, Criteria, Power Converters, and Control Strategies in Microgrids

Electric Vehicles (EV) usage is increasing over the last few years due to a rise in fossil fuel prices and the rate of increasing carbon dioxide (CO2) emissions. The EV charging stations are powered by the existing utility power grid systems, increasing the stress on the utility grid and the load demand at the distribution side. The DC grid-based EV charging is more efficient than the AC distribution because of its higher reliability, power conversion efficiency, simple interfacing with renewable energy sources (RESs), and integration of energy storage units (ESU). The RES-generated power storage in local ESU is an alternative solution for managing the utility grid demand. In addition, to maintain the EV charging demand at the microgrid levels, energy management and control strategies must carefully power the EV battery charging unit. Also, charging stations require dedicated converter topologies, control strategies and need to follow the levels and standards. Based on the EV, ESU, and RES accessibility, the different types of microgrids architecture and control strategies are used to ensure the optimum operation at the EV charging point. Based on the above said merits, this review paper presents the different RES-connected architecture and control strategies used in EV charging stations. This study highlights the importance of different charging station architectures with the current power converter topologies proposed in the literature. In addition, the comparison of the microgrid-based charging station architecture with its energy management, control strategies, and charging converter controls are also presented. The different levels and types of the charging station used for EV charging, in addition to controls and connectors used in the charging station, are discussed. The experiment-based energy management strategy is developed for controlling the power flow among the available sources and charging terminals for the effective utilization of generated renewable power. The main motive of the EMS and its control is to maximize usage of RES consumption. This review also provides the challenges and opportunities for EV charging, considering selecting charging stations in the conclusion.publishedVersio

Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

In the last decade, distribution systems are experiencing a drastic transformation with the advent of new technologies. In fact, distribution networks are no longer passive systems, considering the current integration rates of new agents such as distributed generation, electrical vehicles and energy storage, which are greatly influencing the way these systems are operated. In addition, the intrinsic DC nature of these components, interfaced to the AC system through power electronics converters, is unlocking the possibility for new distribution topologies based on AC/DC networks. This paper analyzes the evolution of AC distribution systems, the advantages of AC/DC hybrid arrangements and the active role that the new distributed agents may play in the upcoming decarbonized paradigm by providing different ancillary services.Ministerio de Economía y Competitividad ENE2017-84813-RUnión Europea (Programa Horizonte 2020) 76409

Economic assessment of a public DC charging station for electric vehicles with load shift capability

This paper presents a new concept of public DC fast charging station for Electric Vehicles (EVs) with load shift capability and simplified interface with renewable energy sources. The key element of the proposed charging system consists in an Energy Storage System (ESS) composed by reused electrochemical batteries from EVs. In the proposed system the energy storage capability is used to smooth the intermittent power demand of fast charging systems for EV batteries, present in public charging stations, and also contributes to the stability of the electrical power grid. When integrated in a Smart Grid, the proposed system may even return some of the energy stored in the EVs batteries back to the power grid, always when it is necessary, in order to improve the power grid operation. In addition to these technical advantages, the proposed topology also presents some interesting economic benefits that are analyzed along the paper.FCT – Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio

Review of Electric Vehicle Charging Technologies, Configurations, and Architectures

Electric Vehicles (EVs) are projected to be one of the major contributors to energy transition in the global transportation due to their rapid expansion. The EVs will play a vital role in achieving a sustainable transportation system by reducing fossil fuel dependency and greenhouse gas (GHG) emissions. However, high level of EVs integration into the distribution grid has introduced many challenges for the power grid operation, safety, and network planning due to the increase in load demand, power quality impacts and power losses. An increasing fleet of electric mobility requires the advanced charging systems to enhance charging efficiency and utility grid support. Innovative EV charging technologies are obtaining much attention in recent research studies aimed at strengthening EV adoption while providing ancillary services. Therefore, analysis of the status of EV charging technologies is significant to accelerate EV adoption with advanced control strategies to discover a remedial solution for negative grid impacts, enhance desired charging efficiency and grid support. This paper presents a comprehensive review of the current deployment of EV charging systems, international standards, charging configurations, EV battery technologies, architecture of EV charging stations, and emerging technical challenges. The charging systems require a dedicated converter topology, a control strategy and international standards for charging and grid interconnection to ensure optimum operation and enhance grid support. An overview of different charging systems in terms of onboard and off-board chargers, AC-DC and DC-DC converter topologies, and AC and DC-based charging station architectures are evaluated

Design and simulation of solar grid-connected charger for electric vehicles

© 2018 IEEE. Electric Vehicles (EV) are playing major role in decreasing carbon emissions. The major problem so far with the Electric Vehicles are overloading the Distribution Grids and availability of enough charging stations. The main objective of this research is to design and install a solar powered charging station for EVs in the UAE environment. This research aims to focus on the need for the shifting from the traditional gas and petrol vehicles to Electric vehicles in the UAE. Additionally, the project intends to ease the problem of the additional load that these EVs impose on the grid by powering the charging station from solar energy. This will help evolve the existing transport system of the UAE into a cleaner and greener system. The project is divided mainly into three important parts. First of all, the system components are designed to match with the ratings of available most common EVs. Then the system has been modelled in DIgSILENT Power factory for the simulation and validation of design. Finally, the results from calculations and simulations are described and compared

Implementation of SiC Power Electronics for Green Energy Based Electrification of Transportation

Increase in greenhouse gas emission poses a threat to the quality of air thus threatening the future of living beings on earth. A large part of the emission is produced by transport vehicles. Electric vehicles (EVs) are a great solution to this threat. They will completely replace the high usage of hydrocarbons in the transport sector. Energy efficiency and reduced local pollution can also be expected with full implementation of electrification of transportation. However, the current grid is not prepared to take the power load of EV charging if it were to happen readily. Moreover, critics are doubtful about the long-term sustainability of EVs in terms of different supply chain issues. The first step for tackling this problem from a research perspective was to do a thorough review of the details of charging in modern day grid. The downsides and lack of futuristic vision. Findings showed that implementing end to end DC based on green energy aided by SiC power electronics. To prove the findings analysis and modelling was done for SiC based charging network. A similar approach was implemented in EV powertrain development. The implementation of SiC power electronics in charging network showed lesser losses, higher thermal conductivity, lesser charging time. The effect on long term battery health and additional circuit was also observed. The cost of production can be reduced by volume manufacturing that has been discussed. In powertrain analysis and simulation the loss and heat reduction one shown on a component-by-component basis. Therefore, this research proposes a Silicon Carbide based end to end DC infrastructure based completely on solar and wind power. The pollution will further be reduced, and energy demands will be met

The system of fast charging station for electric vehicles with minimal impact on the electrical grid

The searching and utilization of new energy sources and technologies is a current trend. The effort to increase the share of electricity production from renewable energy sources is characteristic for economically developed countries. The use of accumulation of electrical energy with a large number of decentralized storage units is most preferred, as well as the focus on the production of energy at the point of its consumption. Modern cogeneration units are a good example. This paper describes the accumulation of electrical energy for equalizing the power balance of electric charging stations with high instantaneous power. The possibility of re-utilization of electrical energy from the charged vehicle in the case of lack of electricity in the power grid is solved at the same time. This paper also deals with the selection of appropriate concept of accumulation system and its cooperation with both renewable and distribution networks. Details of the main power components including the results obtained from the system implementation are also described in this paper

Control of distributed power in microgrids: PV field to the grid, islanding operation, and ultra-fast charging station.

Aquesta tesi explora el control de l'energia distribuïda en microxarxes (MG) i aborda diversos reptes relacionats amb el control, l'estabilitat, la compartició d'energia, el disseny del convertidor d'energia, la connexió a la xarxa, la càrrega ultraràpida i el subministrament d'energia renovable. El rendiment dels MG s'analitza tant en modes d'operació connectats a la xarxa com en illa, considerant diferents configuracions i escenaris de flux d'energia. La tesi se centra en diversos reptes clau, com ara maximitzar l'extracció d'energia de matrius fotovoltaiques (PV) en MG que utilitzen convertidors DC-DC, injectar potència MG excedent a la xarxa principal mitjançant inversors de font de tensió DC-AC (VSI) sota càrregues no lineals i desequilibrades, optimitzant el rendiment de MG i la compartició d'energia en mode illa mitjançant VSI, connectant-se a la xarxa principal en el punt d'acoblament comú (PCC) mitjançant transformadors de baixa freqüència (LFT) i transformadors d'estat sòlid (SST) i explorant topologies de convertidors de potència per ultra -càrrega ràpida de CC de vehicles elèctrics (EV). L'ús de SST en lloc de LFT pot millorar la capacitat de MG alhora que redueix el volum i el pes de l'arquitectura elèctrica MG. Aquesta tesi proporciona coneixements i solucions per abordar els reptes esmentats anteriorment, contribuint a l'avenç del control, l'estabilitat, la qualitat de l'energia i la integració eficient de les fonts d'energia renovables i la càrrega dels vehicles elèctrics.Esta tesis explora el control de la potencia distribuida en microrredes (MGs) y aborda diversos retos relacionados con el control, la estabilidad, el reparto de potencia, el diseño de convertidores de potencia, la conexión a la red, la carga ultrarrápida y el suministro de energías renovables. El rendimiento de las MG se analiza tanto en modo de funcionamiento conectado a la red como en modo aislado, considerando diferentes configuraciones y escenarios de flujo de potencia. La tesis se centra en varios retos clave, como la maximización de la extracción de energía de las matrices fotovoltaicas (FV) en las MG utilizando convertidores CC-CC, la inyección del excedente de energía de las MG en la red principal a través de inversores de fuente de tensión CC-CA (VSI) bajo cargas no lineales y desequilibradas, la optimización del rendimiento de las MG y del reparto de energía en modo aislado mediante VSI, la conexión a la red principal en el punto de acoplamiento común (PCC) mediante transformadores de baja frecuencia (LFT) y transformadores de estado sólido (SST), y la exploración de topologías de convertidores de potencia para la carga ultrarrápida en corriente continua de vehículos eléctricos (VE). El uso de SST en lugar de LFT puede mejorar la capacidad de la MG y, al mismo tiempo, reducir el volumen y el peso de la arquitectura eléctrica de la MG. Esta tesis aporta ideas y soluciones para abordar los retos mencionados, contribuyendo al avance del control de la MG, la estabilidad, la calidad de la energía y la integración eficiente de fuentes de energía renovables y la carga de vehículos eléctricos. Traducción realizada con la versión gratuita del traductor www.DeepL.com/TranslatorThis thesis explores the control of distributed power in microgrids (MGs) and addresses various challenges related to control, stability, power sharing, power converter design, grid connection, ultra-fast charging, and renewable energy supply. The performance of MGs is analysed in both grid-connected and islanded modes of operation, considering different configurations and power flow scenarios. The thesis focuses on several key challenges, including maximising power extraction from photovoltaic (PV) arrays in MGs utilizing DC-DC converters, injecting surplus MG power into the main grid via DC-AC voltage source inverters (VSIs) under nonlinear and unbalanced loads, optimising MG performance and power sharing in islanded mode through VSIs, connecting to the main grid at the point of common coupling (PCC) using low-frequency transformers (LFTs) and solid-state transformers (SSTs), and exploring power converter topologies for ultra-fast DC charging of electric vehicles (EVs). The use of SSTs instead of LFTs can enhance MG capability while reducing the volume and weight of the MG electrical architecture. This thesis provides insights and solutions to address the aforementioned challenges, contributing to the advancement of MG control, stability, power quality, and efficient integration of renewable energy sources and EV charging