Comparison of charging systems for electric vehicles and their impact on electrical grid

This paper presents a comparison of four types of on-board batteries charging systems for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs), and their impact on the power quality of the electrical power grid. In the comparison are analyzed the features, the characteristics and the operation of each charging system, aiming their controllability and their impact on the electrical grid, mainly considering the Total Harmonic Distortion (THD) of the consumed current and the power factor. Besides the normal mode of operation to charge the batteries, denominated Grid-to-Vehicle (G2V), in this paper is also discussed the possibility of operation as Vehicle-to-Grid (V2G), in which the batteries of the Electric Vehicle return part of the stored energy back to the electrical grid. The operation of the batteries charging systems for EVs is shown through simulations and experimental results.FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE)Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/EDAM-SMS/0030/200

Smart charging management for electric vehicle battery chargers

This paper proposes a smart battery charging strategy for Electric Vehicles (EVs) targeting the future smart homes. The proposed strategy consists in regulate the EV battery charging current in function of the total home current, aiming to prevent overcurrent trips in the main switch breaker. Computational and experimental results were obtained under real-time conditions to validate the proposed strategy. For such purpose was adapted a bidirectional EV battery charger prototype to operate in accordance with the aforementioned strategy. The proposed strategy was validated through experimental results obtained both in steady and transient states. The results show the correct operation of the EV battery charger even under heavy load variations.Fundação para a Ciência e Tecnologia within the Project Scope: PEst - OE/EEI/UI0319/201

Experimental comparison of single-phase active rectifiers for EV battery chargers

An experimental comparison of single-phase active rectifiers for electric vehicle (EV) battery chargers is presented and discussed. Active rectifiers are used in on-board EV battery chargers as front-end converters to interface the power grid aiming to preserve the power quality. In this paper, four topologies of active rectifiers are compared: traditional power-factor-correction; symmetrical bridgeless; asymmetrical bridgeless; and full-bridge full-controlled. Such comparison is established in terms of the requirements for the hardware structure, the complexity of the digital control system, and the power quality issues, mainly the grid current total harmonic distortion and the power factor. Along the paper these comparisons are presented and verified through experimental results. A reconfigurable laboratorial prototype of an on-board EV battery charger connected to the power grid was used to obtain the experimental results.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 - 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

Impact of electric vehicles on power quality in a smart grid context

The large dependency of the imported fossil fuels and the soaring oil prices, makes essential the look for alternatives to the traditional people transportation system. The natural bet is the electric mobility, namely Electric Vehicles (EV), and Plug-in Hybrid Electric Vehicles (PHEV). This way, in this paper is analyzed the potential impacts of the battery charging systems on the grid power quality, in a Smart Grid context. It is considered the current consumed, according to a typical electric consumption profile, and the voltage degradation for a large number of houses. Two different types of EV batteries chargers were considered: a traditional charger; and a smart charger with sinusoidal current consumption and unitary power factor. It presents simulation results of the integration of EVs and PHEVs in terms of power quality, and experimental results of a smart charger which was specially developed for EV charging and that allows mitigation of the power quality degradation.Fundação para a Ciência e a Tecnologia (FCT

DC-DC converter with 50 kHz-500 kHz range of switching frequency for passive component volume reduction

This paper presents the relationship of switching frequency towards passive components volume of DC-DC boost converter. Principally, the inductor current ripple and capacitor voltage ripple must be considered in order to design the inductor and capacitor, respectively. By increasing the switching frequency, smaller size and volume of passive component can be designed. As the consequences, the switching loss increases during switching transition at turn-ON and turn-OFF conditions. This paper used soft-switching technique to reduce the switching loss at turn-ON condition. The soft-switching technique is realized by adding resonant circuit in DC-DC boost converter. The effectiveness of resonant circuit will be analysed, thus, the efficiency of the converter can be improved. The range of switching frequency considered in the experimental are 50 kHz to 500 kHz. A 100 W prototype has been developed and tested in order to verify the principle. The switching loss experimentally confirm reduced by implementing soft-switching technique with efficiency converter improved from 96.36% to 97.12% when 500 kHz of switching frequency is considered. The passive components volume reduction is achieved when high switching frequency is used where the total volume of passive component when 50 kHz and 500 kHz are 0.083 dm3 and 0.010 dm3, respectively

The Value of IS to Ensure the Security of Energy Supply – The Case of Electric Vehicle Charging

Replacing the internal combustion engine through electrification is regarded as crucial for future mobility. However, the interactions between a higher number of electric vehicles and the impacts on power plant capacities have not yet been sufficiently investigated. Hence, this paper develops an approach to evaluate the energetic impacts on current power plant capacities that result from a higher market penetration of electric vehicles by 2030. The key aspect of the approach is the quantification of smart charging processes in energetic and economic perspectives. It was found that the implementation has significant energetic and thus economic benefits because of an improved integration of the additional electricity demand. The value of information systems which enable smart charging processes is shown by the calculated cost-saving potentials, resulting from a reduced expansion of the power plant system

Batteries charging systems for electric and plug-in hybrid electric vehicles

Many countries have a large dependence on imported fossil fuels whose prices increase almost every day. Knowing that much of this consumption is for transportation systems, it becomes essential to seek for alternatives. The natural bet is the electric mobility, namely through Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs). However, the wide spread utilization of these vehicles has consequences on the electrical power grid, mainly in terms of load management and electric power quality, which are associated to the batteries charging systems. In this scenario, this chapter assesses the electric mobility integration in Smart Grid context, focusing different approaches to the operation of EVs and PHEVs charging processes and the specifications of the chargers, as well as different topologies of charging systems and their features, modes of operation, typical waveforms, and impact in the electrical power grid in terms of power quality. It is also presented a laboratory prototype of a bidirectional EV charger and shown some experimental results. This prototype was developed to charge the batteries aiming to preserve their lifespan, and to contribute to mitigate the degradation of the power quality. The experimental results show the operation of this prototype during the batteries charging process (G2V – Grid-to-Vehicle operation), and during the delivering of stored energy back to the electrical power grid (V2G – Vehicle-to-Grid operation).FEDER Funds - Operational Program for Competitiveness Factors – COMPETEFundação para a Ciência e a Tecnologia (FCT) - FCOMP-01-0124-FEDER-022674, MITPT/ EDAM-SMS/0030/200

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

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

DESENVOLVIMENTO E IMPLEMENTAÇÃO DE UMA FERRAMENTA DE SIMULAÇÃO DE CASOS PARA ANALISAR O IMPACTO DE VEÍCULOS ELÉTRICOS EM REDES DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Araranguá. Engenharia de Energia.Os veículos elétricos são um futuro cada vez mais próximo da realidade e a sua ampla inserção nas redes de distribuição podem impactar a qualidade e a continuidade do fornecimento de energia elétrica. Portanto, fazem necessários estudos que analisem o estado do sistema elétrico de distribuição perante as novas adversidades que a inserção dos veículos elétricos poderá trazer. Isto posto, a implementação de uma ferramenta de análise de sistemas de distribuição em regime permanente é de fundamental importância. Dessa forma, este trabalho tem como objetivo o desenvolvimento e implementação de uma ferramenta de análise de fluxo de carga em sistemas de distribuição. Sendo assim, essa ferramenta poderá auxiliar em estudos e possibilitar a modelagem de veículos elétricos com o intuito de avaliar o seu impacto em redes de distribuição. Para o desenvolvimento da ferramenta proposta de cálculo de fluxo de carga em regime permanente para sistemas de distribuição, foi utilizado a metodologia da soma de potência (MSP). O algoritmo desenvolvido na plataforma do MATLAB para o cálculo de fluxo de carga utilizando o método MSP foi validado para um caso onde foi possível resolver o problema de forma analítica

Electric Vehicles: V2G for Rapid, Safe, and Green EV Penetration

Low carbon and renewable energy sources (RESs) are fast becoming a key sustainable instrument in meeting the global growth of electricity demand while curbing carbon emissions. For example, the gradual displacement of fossil-fuelled vehicles with electrically driven counterparts will inevitably increase both the power grid baseload and peak demand. In many developed countries, the electrification process of the transport sector has already started in tandem with the installation of multi-GW renewable energy capacity, particularly wind and solar, huge investment in power storage technology, and end-user energy demand management. The expansion of the Electric Vehicle (EV) market presents a new opportunity to create a cleaner and transformative new energy carrier. For instance, a managed EV battery charging and discharging profile in conjunction with the national grid, known as the Vehicle-to-Grid system (V2G), is projected to be an important mechanism in reducing the impact of renewable energy intermittency. This paper presents an extensive literature review of the current status of EVs and allied interface technology with the power grid. The main findings and statistical details are drawn from up-to-date publications highlighting the latest technological advancements, limitations, and potential future market development. The authors believe that electric vehicle technology will bring huge technological innovation to the energy market where the vehicle will serve both as a means of transport and a dynamic energy vector interfacing with the grid (V2G), buildings (V2B), and others (V2X)