Unified power converters for battery charging and traction drive systems for electric vehicles: cost and performance analysis

Electric vehicles (EVs) are a promising solution to mitigate the emission of greenhouse gases and atmospheric pollution. Although EVs existence spans from more than one century, only in the recent years there has been a considerable development in the electric mobility paradigm. This development is also verified in the operation modes for the EV, giving it an important role in smart grids. Moreover, the implementation of unified power converters for battery charging and traction drive systems is also a key topic about EVs, allowing at the same time a hardware reduction and an increasing in its functionalities. However, no economic studies about the practical feasibility of these unified systems for EVs have been reported in the literature. In this context, this paper presents a cost assessment of unified battery charging and traction drive systems for EVs focusing on practical aspects. An economic comparison is performed between a traditional EV and a unified system in order to attain a cost/performance analysis for the unified power converters that can be used in EVs.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by FCT within the Project Scope DAIPESEV – Development of Advanced Integrated Power Electronic Systems for Electric Vehicles: PTDC/EEI-EEE/30382/2017. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency

Integrated system for traction and battery charging of electric vehicles with universal interface to the power grid

This paper proposes an integrated system for traction and battery charging of electric vehicles (EVs) with universal interface to the power grid. In the proposed system, the power electronics converters comprising the traction drive system are also used for the battery charging system, reducing the required hardware, meaning the integrated characteristic of the system. Besides, this interface is universal, since it can be performed with the three main types of power grids, namely: (1) Single-phase AC power grids; (2) Three-phase AC power grids; (3) DC power grids. In these three types of interfaces with the power grid, as well as in the traction drive operation mode, bidirectional operation is possible, framing the integration of this system into an EV in the context of smart grids. Moreover, the proposed system endows an EV with an on-board fast battery charger, whose operation allows either fast or slow battery charging. The main contributes of the proposed system are detailed in the paper, and simulation results are presented in order to attain the feasibility of the proposed system.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT -Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work has been supported by FCT within the Project Scope DAIPESEV - Development of Advanced Integrated Power Electronic Systems for Electric Vehicles: PTDC/EEI-EEE/30382/2017. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283

Implementación de un enchufe inteligente para vehículos eléctricos basado en Arduino

En este Trabajo de Fin de Grado se ha realizado el diseño e implementación de un enchufe inteligente basado en Arduino que puede ser controlado por el usuario mediante una aplicación móvil. El enchufe posee 3 modos diferentes: (i) el modo manual, donde el enchufe se encuentra activado al conectar el vehículo, y por tanto, comienza el proceso de carga, (ii) el modo emergencia, donde el enchufe se encuentra activo hasta que se alcanza un determinado porcentaje de batería y después se espera a realizar la recarga en un periodo donde ésta sea más económica, y (iii) el modo ahorro, donde el enchufe no se activa hasta que un servidor externo determina cuándo es más barato iniciar el proceso de recarga del vehículo.La utilización de este enchufe inteligente otorga al usuario un mecanismo de control a la hora de recargar su vehículo eléctrico y, además, le permite ahorrar dinero en el proceso. En concreto, según nuestras estimaciones, la diferencia de usar el modo de emergencia frente al modo manual puede suponer un 7,5% de ahorro, mientras que usar el modo ahorro permite ahorrar hasta un 21,8% del precio de la energía. Estos datos demuestran que el uso de nuestro enchufe va a ser interesante para los usuarios, además de que puede animarles definitivamente a la hora de adquirir un vehículo eléctrico.<br /

Modello per la gestione di una stazione di ricarica EV supportata da un sistema di accumulo energetico

La mobilità elettrica è certamente uno dei settori industriali più dinamici ed in continuo sviluppo, le incognite sul futuro però non sono certo poche.In questo lavoro si è quindi valutata una possibile stazione di ricarica per veicoli elettrici che garantisce ricariche fast ed ultra fast per tre tipologie diverse di veicoli. Per usufruire di queste potenze senza impegnare troppo la rete si è ritenuto indispensabile l’utilizzo di un accumulatore, inizialmente dimensionato da 160kWh

Efficient Use of the Existing Real Estate Infrastructure for Electric Vehicle Charging

The intention to reduce CO2 emissions in the transport sector is increasing the im- portance of the electric vehicle. In this context, the development of a nationwide charging infrastructure also becomes a central aspect. To avoid a cost explosion, efficient charging strategies are therefore of great importance. In this work, it is analyzed to what extent free line capacities of the existing (build- ing) infrastructure can be used in order to provide new charging stations at low cost. Especially the approach of low power charging plays a central role. For the analysis, charging processes for different building types are simulated and evaluated using Java-based tools. The influence of different input parameters, such as the average distances traveled, on the quality of service of the charging system is analyzed as well. Despite low capacities a high potential becomes visible. Due to comparatively long parking times of the vehicles, higher penetration rates of electric cars result in satisfying charging results too.The low power charging approach can therefore make an enormous impact on a quick expansion of the charging infras- tructure. An equally large potential becomes visible with the analysis of real low power charg- ing data. The results show that for more than half of the charging events the parking time exceeds the pure charging time. In order to use this potential, two optimization approaches are presented within the scope of the work. Their goal is to minimize the total load of the charging system without changing the state of charge of the battery when the customer returns to the vehicle. It shows that peak loads at some locations can be reduced on a scale of up to 50 percent. By using this large peak shaving potential, further charging stations can be installed without unnecessarily large investments

Enhancing the charging process of electric vehicles at residential homes

It is essential to establish smart and efficient charging strategies for electric vehicles, due to the increase of their sales, and especially taking into account that many of these vehicles will be recharged in private parking lots, where the charging point features are limited. In this paper, we propose four different charging methods: the cheapest, the cheapest starting, the low cost, and the last period schemes, as an alternative to the traditional plug and charge method. Our objective is to find better strategies for an automatic, efficient, and scheduled electric vehicles'' charging process, avoiding peak power demands, and promoting recharges at off-peak hours, where electricity prices are low. According to this, a smart charger could use our proposed methods to enhance the charging process at residential homes. To assess our proposal, we simulate the battery recharging of 1 000 vehicles per day during a full year, considering the use of domestic electrical plugs, and real electricity pricing. In Addition, three different scenarios have been simulated: 1) a regular-demand scenario; 2) a high-demand scenario; and 3) an extra-demand scenario, in which the vehicles arrive with an average battery level of only 25%. Simulation results confirm that using our charging methods, we can save between 46.9% to 75.2% in terms of electricity fee while maintaining similar battery levels after the charging process