392 research outputs found

    Smart battery charger for electric mobility in smart grids

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    In this paper is presented the development of a smart batteries charger for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs), aiming their integration in Smart Grids. The batteries charging process is controlled by an appropriate control algorithm, aiming to preserve the batteries lifespan. The main features of the equipment are the mitigation of the power quality degradation and the bidirectional operation, as Grid-to-Vehicle (G2V) and as Vehicle-to-Grid (V2G). During the charging process (G2V), the consumed current is sinusoidal and the power factor is unitary. Along the discharging process (V2G), when the equipment allows delivering back to the electrical power grid a small amount of the energy stored in the batteries, the current is also sinusoidal. The V2G mode of operation will be one of the main features of the Smart Grids, both to collaborate with the electrical power grid to increase stability, and to function as a distributed Energy Storage System (ESS). The functioning of the smart batteries charger is shown through simulation and experimental results, both during the charging (G2V) and the discharging (V2G) modes of operation. Also in this paper are shown and briefly described the roles of the key concepts related with the Smart Grids in terms of Systems and Functional Areas, Power Electronics Systems, and Electric Mobility.This work is financed by FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the project PTDC/EEA-EEL/104569/2008 and the project MIT-PT/EDAM-SMS/0030/2008

    Operation modes for the electric vehicle in smart grids and smart homes: present and proposed modes

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    This paper presents the main operation modes for an electric vehicle (EV) battery charger framed in smart grids and smart homes, i.e., are discussed the present-day and are proposed new operation modes that can represent an asset towards EV adoption. Besides the well-known grid to vehicle (G2V) and vehicle to grid (V2G), this paper proposes two new operation modes: Home-to-vehicle (H2V), where the EV battery charger current is controlled according to the current consumption of the electrical appliances of the home (this operation mode is combined with the G2V and V2G); Vehicle-for-grid (V4G), where the EV battery charger is used for compensating current harmonics or reactive power, simultaneously with the G2V and V2G operation modes. The vehicle-to-home (V2H) operation mode, where the EV can operate as a power source in isolated systems or as an off-line uninterruptible power supply to feed priority appliances of the home during power outages of the electrical grid is presented in this paper framed with the other operation modes. These five operation modes were validated through experimental results using a developed 3.6 kW bidirectional EV battery charger prototype, which was specially designed for these operation modes. The paper describes the developed EV battery charger prototype, detailing the power theory and the voltage and current control strategies used in the control system. The paper presents experimental results for the various operation modes, both in steady-state and during transients

    Electric vehicles on-board battery charger for the future smart grids

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    The recent and massive investments in Electric Vehicles (EVs) reveal a change of paradigm in the transports sector and the proliferation of EVs will contribute to an effective reduction in the emissions of greenhouse gases. Nevertheless, for the electrical power grids EVs will be extra loads, which will require the demand energy to charge their batteries. With the advent of the Smart Grids, besides the usual battery charging mode (Grid-to-Vehicle – G2V), where the batteries receives energy from the power grid, arises a new concept for the users of EVs and for the power grid market, denominated as Vehicle-to-Grid (V2G). In the V2G operation mode, EVs return to the power grid part of the energy stored in their batteries. The V2G concept requires the use of battery chargers for the EVs with bidirectional power flow capability and bidirectional communication with the Smart Grids through Information and Communication Technology (ICT) applications. It is important to highlight that the proliferation of EVs and the impact of their battery chargers on the power grid quality is a matter of concern, since conventional chargers present current harmonics and power factor problems. In this paper it is presented the preliminary studies resulting from a PhD work about a bidirectional battery charger for EVs, which was designed to operate in collaboration with the power grid as G2V and V2G through an ICT application. In this way, it is expectable to contribute to the technological innovation of the electric mobility in Smart Grids. To assess the behavior of the proposed battery charger under different scenarios of operation, a prototype has been developed, and some simulation and experimental results of the battery charger are presented.Fundação para a Ciência e a Tecnologia (FCT); FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foun- dation for Science and Technology of Portugal, under the projects: FCOMP-01-0124- FEDER-022674 an d PTDC/EEA-EEL/104569/200

    Operation modes of battery chargers for electric vehicles in the future smart grids

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    This paper presents an on-board bidirectional battery charger for Electric Vehicles (EVs), which operates in three different modes: Grid-to- Vehicle (G2V), Vehicle-to-Grid (V2G), and Vehicle-to-Home (V2H). Through these three operation modes, using bidirectional communications based on Information and Communication Technologies (ICT), it will be possible to exchange data between the EV driver and the future smart grids. This collaboration with the smart grids will strengthen the collective awareness systems, contributing to solve and organize issues related with energy resources and power grids. This paper presents the preliminary studies that results from a PhD work related with bidirectional battery chargers for EVs. Thus, in this paper is described the topology of the on-board bidirectional battery charger and the control algorithms for the three operation modes. To validate the topology it was developed a laboratory prototype, and were obtained experimental results for the three operation modes.FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the project FCOMP-01-0124- FEDER-022674, and QREN project AAC n.º36/SI/2009 – 1384

    Improved vehicle-for-grid (iV4G) mode: novel operation mode for EVs battery chargers in smart grids

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    The experimental validation of a novel operation mode for electric vehicles (EVs) to support the grid power quality is presented. The proposed operation mode, denominated improved vehicle-for-grid (iV4G), is directly associated with the EVs operation aiming the compensation of power quality problems associated with current harmonic distortion and reactive power, improving the total power factor of the electrical installation. Simultaneously with the proposed iV4G, where the EV injects current harmonics and provides reactive power, the EV can exchange active power with the grid (grid-to-vehicle, G2V, to charge the batteries or vehicle-to-grid, V2G, to deliver energy back to the power grid). In this paper, the proposed iV4G operation mode is experimentally validated with a developed EV battery charger prototype connected to an electrical installation of 230 V, 16 A, 50 Hz. The control strategies of the iV4G operation mode and the used prototype are described in detail along the paper. The achieved results confirm the feasibility and good performance of the proposed iV4G operation mode, working alone, and also when associated with the G2V and V2G operating modes.This work has been supported by FCT project 0302836 NORTE-01-0145-FEDER-030283. This work is also part of the COMPETE: POCI-01-0145-FEDER-007043 and FCT within the Project Scope: UID/CEC/00319/2013. This work isfinanced by the ERDF–European RegionalDevelopment Fund through the Operational Programme forCompetitiveness and Internationalisation–COMPETE 2020Programme, and by National Funds through the Portuguese fundingagency, FCT, within project SAICTPAC/0004/2015–POCI–01–0145–FEDER–016434

    Bidirectional battery charger with grid-to-vehicle, vehicle-to-grid and vehicle-to-home technologies

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    This paper presents the development of na on-board bidirectional battery charger for Electric Vehicles (EVs) targeting Grid-to-Vehicle (G2V), Vehicle-to-Grid (V2G), and Vehicle-to-Home (V2H) technologies. During the G2V operation mode the batteries are charged from the power grid with sinusoidal current and unitary power factor. During the V2G operation mode the energy stored in the batteries can be delivered back to the power grid contributing to the power system stability. In the V2H operation mode the energy stored in the batteries can be used to supply home loads during power outages, or to supply loads in places without connection to the power grid. Along the paper the hardware topology of the bidirectional battery charger is presented and the control algorithms are explained. Some considerations about the sizing of the AC side passive filter are taken into account in order to improve the performance in the three operation modes. The adopted topology and control algorithms are accessed through computer simulations and validated by experimental results achieved with a developed laboratory prototype operating in the different scenarios

    New opportunities and perspectives for the electric vehicle operation in smart grids and smart homes scenarios

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    New perspectives for the electric vehicle (EV) operation in smart grids and smart homes context are presented. Nowadays, plugged-in EVs are equipped with on-board battery chargers just to perform the charging process from the electrical power grid (G2V – grid-to-vehicle mode). Although this is the main goal of such battery chargers, maintaining the main hardware structure and changing the digital control algorithm, the on-board battery chargers can also be used to perform additional operation modes. Such operation modes are related with returning energy from the batteries to the power grid (V2G- vehicle-to-grid mode), constraints of the electrical installation where the EV is plugged-in (iG2V – improved grid-tovehicle mode), interface of renewables, and contributions to improve the power quality in the electrical installation. Besides the contributions of the EV to reduce oil consumption and greenhouse gas emissions associated to the transportation sector, through these additional operation modes, the EV also represents an important contribution for the smart grids and smart homes paradigms. Experimental results introducing the EV through the aforementioned interfaces and operation modes are presented. An on-board EV battery charger prototype was used connected to the power grid for a maximum power of 3.6 kW.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation Ǧ COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015- POCI- 01-0145-FEDER-016434.info:eu-repo/semantics/publishedVersio

    Improved vehicle-to-home (iV2H) operation mode: experimental analysis of the electric vehicle as off-line UPS

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    This paper presents experimental results of electric vehicle (EV) operation as an off-line uninterruptible power supply (UPS). Besides the traditional grid-to-vehicle and vehicle-to-grid modes, this paper presents an improved vehicle-to-home operation mode. This new operation mode consists of the detection of a power outage in the power grid and the change of the EV battery charger control to operate as an off-line UPS. When the power grid voltage is restored, the voltage produced by the on-board EV battery charger is slowly synchronized with the power grid voltage before a complete transition to the normal mode. This paper presents results of two algorithms to detect a power outage: the root mean square (rms) calculation method based on half-cycle of the power grid voltage, and the rms estimation based on a Kalman filter. The experimental results were obtained in steady and transient state considering two cases with the EV plugged in at home:when charging the batteries and without charging the batteries. This paper describes the EV battery charger, the power outage detection methods, and the voltage and current control strategies.- This work was supported by the Fundacao para a Ciencia e Tecnologia (FCT) in the scope of the projects under Grant PEst-UID/CEC/00319/2013. The work of V. Monteiro was supported by the Doctoral Scholarship through the Portuguese FCT Agency under Grant SFRH/BD/80155/2011. The work of B. Exposto was supported by the Doctoral Scholarship through the Portuguese FCT Agency under Grant SFRH/BD/87999/2012.info:eu-repo/semantics/publishedVersio

    On-board electric vehicle battery charger with enhanced V2H operation mode

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    This paper proposes an on-board Electric Vehicle (EV) battery charger with enhanced Vehicle-to-Home (V2H) operation mode. For such purpose was adapted an on-board bidirectional battery charger prototype to allow the Grid-to-Vehicle (G2V), Vehicle-to-Grid (V2G) and V2H operation modes. Along the paper are presented the hardware topology and the control algorithms of this battery charger. The idea underlying to this paper is the operation of the on-board bidirectional battery charger as an energy backup system when occurs a power outages. For detecting the power outage were compared two strategies, one based on the half-cycle rms calculation of the power grid voltage, and another in the determination of the rms value based in a Kalman filter. The experimental results were obtained considering the on-board EV battery charger under the G2V, V2G, and V2H operation modes. The results show that the power outage detection is faster using a Kalman filter, up to 90% than the other strategy. This also enables a faster transition between operation modes when a power outage occurs.Fundação para a Ciência e Tecnologia (FCT), Project Scope: Pest OE/EEI/UI0319/20

    An off-board multi-functional electric vehicle charging station for smart homes: analysis and experimental validation

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    This paper presents the analysis and experimental validation of a single-phase off-board multi-functional electric vehicle (EV) charging station (MF-EVCS), which has a single ac interface and two dc interfaces. As innovative aspects, the proposed MF-EVCS handles the interface of the ac power grid, the dc interface of a renewable energy source (RES), as well as the dc interface of an EV to perform dc charging or discharging of the batteries (in off-board grid-to-vehicle (G2V) or vehicle-to-grid (V2G) modes). Considering the power grid, the individual operation modes of the RES and the EV interfaces can be considered. Moreover, a combination of these modes is also possible. Besides, the MF-EVCS has as key innovative aspect the possibility of operating as an active power filter (APF), supporting the operation with reactive power and/or selected current harmonics. This possibility can be associated with any of the previous mentioned modes. These new features are framed in two distinct scenarios: in a smart home, where the ac-side current can be determined as a function of the other electrical appliances; in a smart grid, where the ac-side current can be determined as a requisite of the power grid. The proposed power theory, as well as the current control strategies for both ac-side and dc-side of the MF-EVCS, are presented in the paper for all the possible operation scenarios. A laboratory prototype was developed to validate the proposed MF-EVCS and the experimental results confirm its suitability for smart homes.INCT-EN -Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção(DAIPESEV PTDC/EEI-EEE/30382/2017
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