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

A Review of Current Research Trends in Power-Electronic Innovations in Cyber-Physical Systems.

In this paper, a broad overview of the current research trends in power-electronic innovations in cyber-physical systems (CPSs) is presented. The recent advances in semiconductor device technologies, control architectures, and communication methodologies have enabled researchers to develop integrated smart CPSs that can cater to the emerging requirements of smart grids, renewable energy, electric vehicles, trains, ships, internet of things (IoTs), etc. The topics presented in this paper include novel power-distribution architectures, protection techniques considering large renewable integration in smart grids, wireless charging in electric vehicles, simultaneous power and information transmission, multi-hop network-based coordination, power technologies for renewable energy and smart transformer, CPS reliability, transactive smart railway grid, and real-time simulation of shipboard power systems. It is anticipated that the research trends presented in this paper will provide a timely and useful overview to the power-electronics researchers with broad applications in CPSs.post-print2.019 K

Wide-Area Time-Synchronized Closed-Loop Control of Power Systems And Decentralized Active Distribution Networks

The rapidly expanding power system grid infrastructure and the need to reduce the occurrence of major blackouts and prevention or hardening of systems against cyber-attacks, have led to increased interest in the improved resilience of the electrical grid. Distributed and decentralized control have been widely applied to computer science research. However, for power system applications, the real-time application of decentralized and distributed control algorithms introduce several challenges. In this dissertation, new algorithms and methods for decentralized control, protection and energy management of Wide Area Monitoring, Protection and Control (WAMPAC) and the Active Distribution Network (ADN) are developed to improve the resiliency of the power system. To evaluate the findings of this dissertation, a laboratory-scale integrated Wide WAMPAC and ADN control platform was designed and implemented. The developed platform consists of phasor measurement units (PMU), intelligent electronic devices (IED) and programmable logic controllers (PLC). On top of the designed hardware control platform, a multi-agent cyber-physical interoperability viii framework was developed for real-time verification of the developed decentralized and distributed algorithms using local wireless and Internet-based cloud communication. A novel real-time multiagent system interoperability testbed was developed to enable utility independent private microgrids standardized interoperability framework and define behavioral models for expandability and plug-and-play operation. The state-of-theart power system multiagent framework is improved by providing specific attributes and a deliberative behavior modeling capability. The proposed multi-agent framework is validated in a laboratory based testbed involving developed intelligent electronic device prototypes and actual microgrid setups. Experimental results are demonstrated for both decentralized and distributed control approaches. A new adaptive real-time protection and remedial action scheme (RAS) method using agent-based distributed communication was developed for autonomous hybrid AC/DC microgrids to increase resiliency and continuous operability after fault conditions. Unlike the conventional consecutive time delay-based overcurrent protection schemes, the developed technique defines a selectivity mechanism considering the RAS of the microgrid after fault instant based on feeder characteristics and the location of the IEDs. The experimental results showed a significant improvement in terms of resiliency of microgrids through protection using agent-based distributed communication

Control and stability of Ac/Dc microgrids

The current society is facing several challenges related to the field of energy, such as the high dependency on fossil fuels, the constant increment in the energy consumption and the environmental problems caused by these factors. The integration of distributed generation systems—mainly based on renewable energies—combined with energy storage systems is the most interesting solution to tackle these issues. However, most of these systems are connected to the grid through electronic converters that actively control the power exchange. This fact causes various problems not suffered since the origins of electric grids in the transition from an electric model dominated by synchronous machines to a model where power electronics gain more importance—even being the dominating systems in some cases. The lack of inertial response and primary reserve, the instabilities caused by the interactions of power electronic systems or the premature situation of direct current grids, which are being employed more widely, stand out as some of the most important challenges that we want to address with this thesis. In this context, the main purpose of the thesis is the development of ac/dc microgrid control strategies that improve the dynamic behaviour of the system. In order to achieve this objective we contemplate four main lines that consist of the identification and analysis of different microgrid topologies and control techniques, the study of primary control operation modes of the systems that compose these microgrids and finally the the development and evaluation of various low-level control strategies for ac and dc microgrids. These techniques are based on the concept of operation of classical synchronous generators, enabling their autonomous operation as well as providing inertial response under grid perturbations. Among the contributions of the thesis, we can highlight on the one hand, the analysis and comparative evaluation of synchronous machine emulation techniques for ac microgrids, where we evaluate their behaviour for different types of perturbations and we examine their stability applying the generalized Nyquist criterion. Regarding dc microgrids, on the other hand, we propose novel control techniques that are analogous to the ones analysed for ac grids. We call these techniques virtual-capacitors, as they emulate the behaviour of these passive elements connected to dc grids. In this case, we thoroughly study their transient as well as steady-state behaviour, and we demonstrate that they can be adapted by simply modifying control parameters. Moreover, we analyse the stability of these techniques through parametric analysis of their dominant eigenvalues.Gaur egungo gizartea energiaren arloko hainbat erronkaren aurrean aurkitzen da, besteak beste, erregai fosilekiko dependentzia handia, kontsumo energetikoaren etengabeko igoera, eta faktore hauek eragiten dituzten ingurumen arazoak. Generazio bananduko sistemen integrazioa—bereziki iturri berriztagarrietan oinarritutakoa—metatze sistemekin bateratuta, arazo horiei aurre egiteko aukera interesgarriena bilakatu da. Hala ere, sistema hauetako gehienak bihurgailu elektronikoen bitartez konektatzen dira sare elektrikotara, potentziaren hartu-emana modu aktiboan kontrolatzen dutelarik. Honek, makina sinkronoez menderatutako modelo elektriko batetik, potentzia elektronika garrantzia hartzen hasten den—edo kasu batzuetan mendean dagoen—modelo baterako trantsizioan hainbat arazo eragiten ditu, sare elektrikoak sortu zirenetik jasan ez direnak. Erantzun inertzial eta erreserba primario eza, bihurgailuen interakzioaren ondoriozko estabilitate arazoak edo korronte zuzeneko sareen egoera goiztiarra, geroz eta gehiago erabiltzen direnak, tesi honen bitartez aurre egin nahi diren erronkarik garrantzitsuenetarikoak dira. Testuinguru honetan, tesiaren helburu nagusia ac/dc mikrosareen portaera dinamikoa hobetzen duten kontrol estrategiak garatzea da. Helburu hau lortzeko lau lerro nagusi planteatu dira, besteak beste, mikrosareen topologia eta kontrol estrategia desberdinen identifikazio eta analisia, sare hauek konposatzen duten sistemen kontrol primarioaren untzionamendu motak azterketa, eta azkenik, bai ac eta bai dc mikrosareendako nibel baxuko kontrol estrategia desberdinen garapena. Azken hauek generadore sinkrono klasikoetan oinarritu dira, modu autonomoan eta bananduan aritzeko gaitasuna emateaz gain, sareko perturbazioen aurrean erantzun inertziala ematea ahalbidetzen dielako. Tesiaren ekarpenen artean, alde batetik, makina sinkronoen emulazioan datzan kontrol estrategien analisia eta konparaketa azpimarratu behar dira. Kasu honetan, teknika hauek hainbat perturbazioetarako ebaluatzen ditugu, eta Nyquisten kriterio generalizatuan oinarrituta estabilitatea aztertzen dugu. Korronte zuzeneko sareei erreparatuz, bestalde, kontrol teknika berriak proposatzen ditugu. Hauei kondentsadore-birtual izena ezarri diegu, elementu pasibo horien erantzun dinamikoa emulatzen dutelako. Hemen, teknika hauen erregimen iraunkorreko eta iragankorreko erantzuna aztertzen dugu, soilik kontrol parametro batzuk aldatuta egokitu daitezkela frogatuz. Hortaz gain, sistema hauen estabilitatea aztertzen dugu berezko balio dominanteen (eigenvalue-en) analisi parametrikoak eginez.La sociedad actual se enfrenta a varios retos importantes en materia energética, entre los que destacan la gran dependencia de los combustibles fósiles, el constante aumento del consumo energético y los problemas medioambientales que estos factores conllevan. La integración de sistemas de generación distribuida—principalmente de origen renovable— combinadas con sistemas de almacenamiento de energía, se presenta como la solución más interesante para hacer frente a estos retos. Sin embargo, la mayor parte de estos sistemas se conectan a la red a través de convertidores electrónicos que controlan el intercambio de potencia de manera activa. Este hecho hace que la transición desde un modelo eléctrico principalmente dominado por máquinas síncronas, hacia un modelo donde la electrónica de potencia comienza a cobrar protagonismo—hasta el punto de llegar a ser dominante en algunos casos—acarree diversos problemas que prácticamente no se han manifestado desde los orígenes de las redes eléctricas. La falta de respuesta inercial y reserva primaria, las inestabilidades debidas a la interacción de los sistemas electrónicos de potencia o la prematura situación de las redes de corriente continua, cada día utilizadas en mayor medida, destacan como algunos de los retos más importantes a los que se quiere dar respuesta a través de esta tesis. En este contexto, el objetivo principal de la tesis es el desarrollo de estrategias de control de microrredes ac/dc que mejoren el comportamiento dinámico del sistema. Para la consecución de este objetivo se han planteado cuatro líneas principales que constan de la identificación y análisis de diferentes topologías y técnicas de control de microrredes, el estudio de los modos de operación del control primario de los sistemas que las componen, y finalmente, el desarrollo y evaluación de diversas técnicas de control de nivel bajo tanto para microrredes ac como dc. Las estrategias de control de nivel bajo desarrolladas en la tesis se basan en el concepto de operación de los generadores síncronos clásicos, lo que les permite operar de manera distribuida y autónoma, aportando a su vez respuesta inercial ante perturbaciones en la red. Entre las contribuciones de la tesis destacan, por un lado, el análisis y comparativa de técnicas de control de emulación de máquinas síncronas para redes ac, donde evaluamos su comportamiento ante diferentes tipos de perturbaciones y examinamos su estabilidad aplicando criterios generalizados de Nyquist. En el ámbito de las redes dc, por otra parte, proponemos nuevas técnicas de control que son análogas a las analizadas para las redes ac, y que denominamos como condensadores-virtuales puesto que emulan el comportamiento dinámico de estos elementos pasivos conectados a la red. En este caso, estudiamos en detalle su comportamiento dinámico y en régimen permanente, demostrando que se pueden adaptar simplemente variando parámetros de control, y analizamos su estabilidad llevando a cabo análisis paramétricos de sus valores propios dominantes

Three-Port Bi-Directional DC–DC Converter with Solar PV System Fed BLDC Motor Drive Using FPGA

The increased need for renewable energy systems to generate power, store energy, and connect energy storage devices with applications has become a major challenge. Energy storage using batteries is most appropriate for energy sources like solar, wind, etc. A non-isolated three-port DC–DC-converter energy conversion unit is implemented feeding the brushless DCmotor drive. In this paper, a non-isolated three-port converter is designed and simulated for battery energy storage, interfaced with an output drive. Based on the requirements, the power extracted from the solar panel during the daytime is used to charge the batteries through the three-port converter. The proposed three-port converter is analyzed in terms of operating principles and power flow. An FPGA-based NI LabView PXI with SbRio interface is used to develop the suggested approach’s control hardware, and prototype model results are obtained to test the proposed three-port converter control system’s effectiveness and practicality. The overall efficiency of the converter’s output improves as a result. The success rate is 96.5 percent while charging an ESS, 98.1 percent when discharging an ESS, and 95.7 percent overall