Experimental validation of a novel architecture based on a dual-stage converter for off-board fast battery chargers of electric vehicles

The experimental validation of a novel architecture of an off-board, three-phase fast battery charger for electric vehicles (EVs) with innovative operation modes is presented in this paper. The proposed EV fast battery charger is based on a dual-stage power converter (ac-dc and dc-dc) sharing the same dc link. The ac-dc stage is used as an interface between the power grid and the dc link. It is composed of the parallel association of two full-bridge voltage-source converters, and allows control of the grid current and of the dc-link voltage. The dc-dc stage is used as an interface between the dc link and the batteries. It is constituted by a bidirectional three-level asymmetrical voltage-source converter, and controls the flux of current during the EV battery charging process. Compared with the traditional solutions used for EV fast battery chargers, the proposed architecture operates as an interleaved converter, facilitating the reduction of the passive filters size, and the grid current harmonic distortion for the same switching frequency. Throughout the paper, the ac-dc and dc-dc stages, and the digital control algorithms are described in detail. The experimental validation was performed in a laboratory using a developed EV fast battery charger prototype, operating through the grid-to-vehicle and the proposed charger-to-grid modes, exchanging active, and reactive power with the power grid.ERDF - European Regional Development Fund()info:eu-repo/semantics/publishedVersio

Unified power converter based on a dual-stator permanent magnet synchronous machine for motor drive and battery charging of electric vehicles

An electric vehicle (EV) usually has two main power converters, namely one for the motor drive system and another for the battery-charging system. Considering the similarities between both converters, a new unified power converter for motor drive and battery charging of EVs is propounded in this paper. By using a single unified power converter, the cost, volume, and weight of the power electronics are reduced, thus also making possible a reduction in the final price of the EV. Moreover, the proposed unified power converter has the capability of bidirectional power flow. During operation in traction mode, the unified power converter controls motor driving and regenerative braking. Additionally, during operation in battery-charging mode, with the EV plugged into the electrical power grid, the unified power converter controls the power flow for slow or fast battery charging (grid-to-vehicle (G2V) mode), or for discharging of the batteries (vehicle-to-grid (V2G) mode). Specifically, this paper presents computer simulations and experimental validations for operation in both motor-driving and slow battery-charging mode (in G2V and V2G modes). It is demonstrated that the field-oriented control used in the traction system presents good performance for different values of mechanical load and that the battery-charging system operates with high levels of power quality, both in G2V and in V2G mode.This work was supported by the Portuguese Foundation of Science and Technology (FCT) (in Portuguese, Fundação para a Ciência e Tecnologia) within the R&D Units Project Scope: UIDB/00319/2020. This work was also supported by the FCT Project DAIPESEV PTDC/EEIEEE/30382/2017 and by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017. T.J.C.S. is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the FCT

OnBoard reconfigurable battery charger for electric vehicles with traction-to-auxiliary mode

This paper proposes a single-phase reconfigurable battery charger for Electric Vehicle (EV) that operates in three different modes: Grid-to-Vehicle (G2V) mode, in which the traction batteries are charged from the power grid; Vehicle-to-Grid (V2G) mode, in which the traction batteries deliver part of the stored energy back to the power grid; and in Traction-to-Auxiliary (T2A) mode, in which the auxiliary battery is charged from the traction batteries. When connected to the power grid, the battery charger works with sinusoidal current in the AC side, for both G2V and V2G modes, and also regulates the reactive power. When the EV is disconnected from the power grid, the control algorithms are modified and the full-bridge AC-DC bidirectional converter works as a full-bridge isolated DC-DC converter that is used to charge the auxiliary battery of the EV, avoiding the use of an additional charger to accomplish this task. To assess the behavior of the proposed reconfigurable battery charger under different operation scenarios, a 3.6 kW laboratory prototype has been developed and experimental results are presented.ER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the projec ts: FCOMP - 01 - 0124 - FEDER - 022674, PTDC/EEA - EEL/104569/2008, AAC nº 36/SI/2009/13844, and MIT - PT/EDAM - SMS/0030/2008

Traction and charging systems for an electric motorcycle

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores (área de especialização em Electrotecnia e Sistemas de Energia)With the current mobility paradigm, it is proven that excessive energy consumption and low energy efficiency are harming the planet and deteriorating human life conditions. Therefore it is required to substitute Internal Combustion Engines (ICEs) for electric motors and consequently shift gradually to fully electric vehicle (EV) fleets. The electrification of mobility is one of the most researched topics in all technology fields. These efforts put society closer to achieve energy sustainability and reduce the negative human impact on the environment. With this, low energy consumption vehicles such as electric motorcycles (EMs) are a very viable solution to reduce energy consumption. Due to their low power and weight, EMs have high energy efficiency and are optimized for urban transit. In this context, it becomes necessary to develop systems and prototypes common to any EV. Therefore the focus of this thesis is to implement motor traction and battery charging systems for an EM. One of the most important characteristics of an electric traction system is the possibility of applying regenerative braking. Regenerative braking converts the mechanical energy, otherwise dissipated by conventional brakes, into reusable energy that is sent back to the batteries. This process occurs due to the operation of the traction system’s power converter and improves greatly the energy efficiency of the EV. Besides, is proposed that the traction system’s input is a hand accelerator that can control the motor speed/torque. The charging system acts as an interface between the power grid and the motorcycle system. In applications such as EV charging, it is important to ensure power quality in order to maintain the developed system and the power grid healthy. With this, the first stage of the charger is AC-DC rectification and besides regulating the DC-link voltage should also act as a Power Factor Corrector (PFC) and compensate current harmonics. Secondly, the charger system should be able to regulate and control the charging process by maintaining a constant current, voltage, or temperature. The charger should also ensure the battery’s safety, and offer the possibility of regulating the charging speed. This document, details the development of traction and charger systems from the state of the art research and topologies presentation, to the computational simulations, and respective experimental tests/validation.Com o paradigma da mobilidade é evidente que o consumo excessivo de energia proveniente de combustíveis fosseis está a prejudicar o planeta. Por conseguinte, é necessário substituir os Motores de Combustão Interna (MCI) por motores eléctricos e, consequentemente, transitar gradualmente para frotas de veículos 100% elétricos (VE). A eletrificação da mobilidade é um dos tópicos com mais investimento em investigação de todos os campos tecnológicos. Estes esforços aproximam a sociedade para alcançar a sustentabilidade energética e reduzir o impacto humano no ambiente através da extração de combustíveis fósseis. Com isto, veículos de baixo consumo energético, tais como motociclos eléctricos (ME), são uma solução muito viável. Devido à sua baixa potência e peso, os MEs possuem elevada eficiência energética e são optimizados para o trânsito urbano.. Neste contexto, torna-se necessário o desenvolvimento de sistemas e protótipos comuns a qualquer EV. Portanto, o foco desta dissertação é a implementação dos sistemas de tração para um motor e de carregamento de baterias para um ME. Uma das características mais importantes de um sistema de tracção elétrica é a possibilidade de aplicar travagem regenerativa. A travagem regenerativa converte a energia mecânica, de outro modo dissipada pelos travões convencionais, em energia reutilizável que é reenviada para as baterias. Este processo ocorre devido ao funcionamento do conversor do sistema de tracção e aumenta a eficiência energética do VE. Além disso, é proposto que o sistema de tracção seja controlado através de um acelerador manual que pode controlar a velocidade/torque do motor. O sistema de carregamento actua como interface entre a rede elétrica e o motociclo. Em aplicações como o carregamento de VEs, é importante assegurar a qualidade da energia tanto do sistema desenvolvido como da rede de elétrica. Com isto, a primeira fase do carregador, para além de regular a tensão DC, deve também actuar como corrector do factor de potência (PFC). Em segundo lugar, o sistema carregador deve ser capaz de regular e controlar o processo de carregamento mantendo uma corrente, tensão ou temperatura constantes. O carregador, para além de fazer a interface entre o DC-link e a bateria, deve oferecer a possibilidade de regular a taxa de carregamento. Este documento, detalha o desenvolvimento de sistemas de tracção e carregamento desde a investigação e apresentação das topologias mais utilizadas, até às simulações computacionais, e respectivos testes experimentais/validação

Power electronics converters for an electric vehicle fast charging station with storage capability

Fast charging stations are a key element for the wide spreading of Electric Vehicles (EVs) by reducing the charging time to a range between 20 to 40 min. However, the integration of fast charging stations causes some adverse impacts on the Power Grid (PG), namely by the huge increase in the peak demand during short periods of time. This paper addresses the design of the power electronics converters for an EV DC fast charging station with local storage capability and easy interface of renewables. In the proposed topology, the energy storage capability is used to smooth the peak power demand, inherent to fast charging systems, and contributes to the stability of the PG. When integrated in a Smart Grid, the proposed topology may even return some of the stored energy back to the power grid, when necessary. The accomplishment of the aforementioned objectives requires a set of different power electronics converters that are described and discussed in this paper.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and by FCT within the Project Scope: UID/CEC/00319/2013. 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

A unified topology for the integration of electric vehicle, renewable energy source, and active filtering for the power quality improvement of the electrical power grid: an experimental validation

Electrical power grids are facing challenges concerning new linked technologies and associated contributions of power electronics, both regarding innovative topologies of power converters and advanced power management algorithms. Additionally, technologies related to renewables and electric mobility have several points in common, especially about the interface with the power grid, which allows to foresee a convergence for unified solutions in the power grid interface, without jeopardizing the functionalities and added values of each technology. Encompassing this purpose, this paper presents a unified topology, based on a three-phase structure, which, in addition to a collaborative operation with the power grid targeting the compensation of power quality problems, also enables the integration of a renewable energy source and an electric vehicle. The main contribution of this paper resides in the fact that only an interface with the power grid is necessary to involve three central features of smart grids: renewables, electric mobility, and power quality. Overall, the unified topology presents a four-quadrant structure, both in the perspective of AC and DC interfaces, offering multiple functionalities, mainly to the power grid. In the AC interface, the structure operates in interleaved mode, while in the DC interface, the structure operates in multilevel mode. The global control algorithm is presented, covering the interconnection between the mentioned technologies, as well as the details of implementation of the individual control algorithms regarding each interface. A laboratory prototype, connected to a three-phase 400 V-50 Hz power grid, was used to obtain an experimental validation for a maximum operating power of 12.5 kW, corroborating the essential advantage characteristics and the correct functioning of the presented unified topology.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEIEEE/30283/2017 and by the FCT Project DAIPESEV PTDC/EEIEEE/30382/2017

Active, Reactive and Harmonic Control for Distributed Energy Micro-Storage Systems in Smart Communities Homes

This paper aims to provide control strategies for distributed micro-storage energy systems at the residential level to contribute to smart grid goals. A simulation model of an energy storage system (ESS) charger has been implemented to test these proposed control strategies. The smart community energy management system (SCEMS), acting as an aggregator of resources in the community according to the expected demand and production, sends to each individual home the active and reactive power set-points. Besides, in case the ESS has available capacity, once the SCEMS requirements are satisfied, it is used to absorb the harmonic current components demanded by the household circuitry. It allows a local improvement in the power quality of the demanded current, and thus contributes to the global power quality consumption of the community. Simulation results showing the operation of a local ESS at a home in a Smart Community are presented to validate the proposed control strategies

Design and implementation of a three-phase boost battery charger with PFC using CompactRIO control system : design, simulation and implementation of a 3-phase boost battery charger

In a plug-in hybrid electric vehicle, the utility grid charges the vehicle battery through a battery charger. For a three-phase grid supply voltage, three-phase boost rectifiers are commonly used as chargers. Bi-directional power transfer capability and unit power factor operation become desirable features due to the increasing power quality requirements on the grid-connected converters. The Voltage Oriented Control is one of the methods based on high performance dq-coordinate controllers which satisfies the increasing power quality requirements. The Voltage Oriented Control method for a three-phase boost rectifier has been designed, simulated and implemented. The system simulation is performed using Matlab/Simulink software as well as Labview. A feedforward decoupled current controller is designed along with a Pulse Width Modulation scheme to control the battery charging. The controller, consisting of a current controller and a DC-link voltage controller, is designed using a method called Internal Model Control. A National Instruments CompactRIO system is used for practical implementation. The system directly runs a Labview model to execute the control. The Labview files are developed for this purpose. A brief explanation of the system configuration is provided for the experimental system. ____________________________________________________________________________________________________________Los vehículos eléctricos e híbridos usan potencia de la red para cargar sus baterías y mientras lo hacen el sistema de tracción no está en uso. Debido a que el sistema de carga y el de tracción no están en uso al mismo tiempo, el inversor y el motor eléctrico pueden ser usados como rectificador evitando el uso redundante de componentes. Para hacer esto, un motor con dos juegos de devanados puede ser usado consiguiendo en el cargador una reducción considerable de peso, volumen y precio. El cargador propuesto en un cargador aislado de alta potencia que usa la mitad de los devanados del motor durante la carga usando el motor como si fuera un transformador. El uso de este motor especifico nos proporcionará aislamiento que será beneficioso por razones de seguridad. El objetivo principal de este proyecto fin de carrera es el diseño y la implementación de un cargador integrado para un coche eléctrico o híbrido con un nivel de potencia de 15 kW programando un control para el inversor que consiga tener un factor de potencia unitario.Ingeniería Industria

Active and Reactive Power Controller for Single Phase PV Grid Connected Inverter with LCL Filter

This thesis work is concentrated on Photovoltaic system connected with grid by an inverter to control Active Power and Reactive Power independently and reducing THD using LCL filter. Many exciting methods to control power are based on synchronous reference frame transformation, this method requires information on phase angle given by Phase-Locked loop (PLL). At first PV cell characteristics are drawn that help in making the proposed Photovoltaic system. PLL is avoided and a controller is designed for single phase grid connected inverter system connected with a LCL filter in stationary reference frame. To achieve necessary performance with independent control of active and reactive power injected in the grid the decoupling control strategies is adopted. As compared with orthodox control scheme of controlling power for single phase PV grid present scheme is highly reliable, fast in response and active and reactive power is controlled independently. Present control algorithm is easier and simpler as this scheme is implemented in stationary reference frame. To confine high resonant peak value active damping technique is used in the designed current controller. LCL filter designing has been done in such a way to reduce the net THD and total losses taking place in the inductor of the filter. Switching scheme of the inverter and LCL filter are used to obtain sinusoidal output phase voltage. Lastly, the proposed control scheme helps in controlling the THD and independent control of active and reactive power are achieved without PLL in the system. Dynamic performance of the system is analysed and various waveforms are studied using MATLAB/Simulink 2014

Hall-Effect Based Semi-Fast AC On-Board Charging Equipment for Electric Vehicles

The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented