Review on Key Factors of Wireless Power Transfer Technology for Electric Vehicles

Electric vehicles (EVs) have become an alternative option for a clean energy society. A new charging technology which is wireless charging has been developed to satisfy the limitations of EVs which are the electric drive range and battery storage. Companies like Tesla, BMW, and Nissan have already started to develop wireless charging for EVs. This paper presents a literature review on wireless charging of EVs. The existing technologies for Wireless Power Transfer (WPT) system are summarized for different power applications. Coil design plays the most vital role in the WPT system so the different coil design with the transferred efficiency is reviewed. The other important parameters and technical components like significant factors of WPT system, track layout of dynamic wireless charging, foreign object detection method, and position alignment method that are affecting the efficiency of the wireless charging system are also discussed. Lastly, health and safety concerns for human beings and living things are investigated

Best practice guide for the assessment of EMF exposure from vehicle Wireless Power Transfer systems

open11sì(Editors: Roberta Guilizzoni, Stuart Harmon, Mauro Zucca)This document is based on the experience gained by the partners involved in the EMPIR Project 16ENG08 "Metrology for inductive charging of electric vehicles (MICEV)" (www.micev.eu). The project addressed the electromagnetic metrology and human exposure problems related to inductive charging of electric vehicles, both from a modelling and a measurement point of view. The guidelines reported here are designed for people who approach the assessment of human exposure in vehicles and around inductive charging stations. These guidelines are intended to complement the published standards in use and those currently being developed by international technical organisations and bodies. This document concerns the charging of electric vehicles, for transmitted power up to 200 kW. The frequency range of interest is related to resonant coils that produce significant electromagnetic field (EMF) emissions from the charging station. Resonant coils operate in the frequency range between 20 kHz and 85 kHz. Their electric current, and thus the magnetic field and harmonic distortion, is very low and not significant in relation to human exposure guidelines. Consequently, the frequency range of interest for human exposure does not exceed 100 kHz. This guide seeks to assemble the experience gained in the field of human exposure assessment and to provide information for the assessment of exposure through experimental measurements and validated calculations. The calculation of the induced quantities, in particular the induced electric field and electric currents in the tissues, is of fundamental importance for the determination of human exposure. From the point of view of dosimetry, for obvious reasons of feasibility, the calculation replaces the measurement. Therefore, a whole chapter of this guide covers the choice of instruments and the description of the correct settings for both the magnetic field calculations and the dosimetric calculations. The document particularly focuses on the following challenges: • the testing framework, including the common layout of charging stations, with reference to the normative and EU Directive on magnetic field exposure (Sections 4 to 6); • means and methods to perform: o measurements of the magnetic flux density in and around a vehicle; o measurements of limb currents (Section 7); • means and methods to perform: o analytical calculation of magnetic flux density levels for EMF exposure assessment; o computation of the induced electric fields in human beings (Section 8). The guidelines contain some appendices, which include the following: a real example of a charging station; some tables with the exposure limits referred to in this guide; a brief comparison between two existing standards; a test case of a numerical code to calculate the sources; some results on the sensitivity of simulated exposure metrics to the variations in tissue properties and, finally, the measurement capabilities of European national metrological institutes concerning AC magnetic fields at the frequency range of interest for Wireless Power Transfer systems (WPTs). These guidelines do not intend to discuss the implementation of wireless charging systems, the design of their components or the optimisation of their performance, as they do not discuss the interoperability or the techniques for building the systems, or their classification. Risk analysis and mitigation measures are beyond the scope of this guideopenAnkarson, Peter; Bottauscio, Oriano; Clarke, Bob; Freschi, Fabio; Guilizzoni, Roberta; Harmon, Stuart; Laporta, Erika; Pichon, Lionel; Bruna Romero, Jorge; Zilberti, Luca; Zucca, MauroAnkarson, Peter; Bottauscio, Oriano; Clarke, Bob; Freschi, Fabio; Guilizzoni, Roberta; Harmon, Stuart; Laporta, Erika; Pichon, Lionel; Bruna Romero, Jorge; Zilberti, Luca; Zucca, Maur

A Review of Commercial Electric Vehicle Charging Methods

Electric Vehicles (EVs) are rapidly becoming the forerunners of vehicle technology. First electric vehicles were overlooked because of not having adequate battery capacity and because of low efficiency of their electric motors. Developing semiconductor and battery technologies increased the interest in the EVs. Nevertheless, current batteries still have insufficient capacity. As a result of this, vehicles must be recharged at short distances (approximately 150 km). Due to scheduled departure and arrival times EVs appear to be more suitable for city buses rather than regular automobiles. Thanks to correct charging technology and the availability of renewable energy for electric buses, the cities have less noise and CO2 emissions. The energy consumption of internal combustion engines is higher than of the electric motors. In this paper, studies on the commercial electric vehicle charging methods will be reviewed and the plug-in charging processes will be described in detail. This study strives to answer the questions of how plug-in charging process communication has performed between the EV and Electric Vehicle Supply Equipment (EVSE).</p

Challenges and Barriers of Wireless Charging Technologies for Electric Vehicles

Electric vehicles could be a significant aid in lowering greenhouse gas emissions. Even though extensive study has been done on the features and traits of electric vehicles and the nature of their charging infrastructure, network modeling for electric vehicle manufacturing has been limited and unchanging. The necessity of wireless electric vehicle charging, based on magnetic resonance coupling, drove the primary aims for this review work. Herein, we examined the basic theoretical framework for wireless power transmission systems for EV charging and performed a software-in-the-loop analysis, in addition to carrying out a performance analysis of an EV charging system based on magnetic resonance. This study also covered power pad designs and created workable remedies for the following issues: (i) how power pad positioning affected the function of wireless charging systems and (ii) how to develop strategies to keep power efficiency at its highest level. Moreover, safety features of wireless charging systems, owing to interruption from foreign objects and/or living objects, were analyzed, and solutions were proposed to ensure such systems would operate as safely and optimally as possible

How driver behaviour and parking alignment affects inductive charging systems for electric vehicles

AbstractInductive charging, a form of wireless charging, uses an electromagnetic field to transfer energy between two objects. This emerging technology offers an alternative solution to users having to physically plug in their electric vehicle (EV) to charge. Whilst manufacturers claim inductive charging technology is market ready, the efficiency of transfer of electrical energy is highly reliant on the accurate alignment of the coils involved. Therefore understanding the issue of parking misalignment and driver behaviour is an important human factors question, and the focus of this paper. Two studies were conducted, one a retrospective analysis of 100 pre-parked vehicles, the second a dynamic study where 10 participants parked an EV aiming to align with a charging pad with no bay markings as guidance. Results from both studies suggest that drivers are more accurate at parking laterally than in the longitudinal direction, with a mean lateral distance from the centre of the bay being 12.12 and 9.57cm (retrospective and dynamic studies respectively) compared to longitudinally 23.73 and 73.48cm. With current inductive charging systems having typical tolerances of approximately ±10cm from their centre point, this study has shown that only 5% of vehicles in both studies would be aligned sufficiently accurately to allow efficient transfer of electrical energy through induction

Inductive power transfer for automotive applications: State-of-the-art and future trends

The paper discusses the status of the development status of the inductive power transmission for automotive applications. This technology is, in fact, gaining the interest of electric vehicle manufacturers as an effective strategy to improve the market penetration of electric mobility. Starting from the origin of this technology, the paper presents an overview of the current state-of-the-art as well as the current research and industrial projects. Particular attention is devoted to the description of a prototypal system for the dynamic inductive power transmission whose goal is to extend the battery range by a fast partial recharging during the movement of the vehicle

Energy Efficiency Analysis through Misalignment on New Design of Hexagonal Coil Array in Wireless Power Transfer

The global transportation revolution accelerates the growth of the Electric Vehicle (EV) market. Wireless Power Transfer Technology (WPT) is part of an alternative solution to replace charging by cable. In its implementation the driver's parking behavior affects Power Transfer Efficiency (PTE) due to frequently misalignment. A new coil array design proposed to optimize PTE and reduce the size of receiver coil. Receiver and transmitter circuits designed to simulate parking conditions and parking lots in small scale settings to get PTE data. Experimental results show that PTE increased by 10% in the center of the coil design and 82% during misalignment on a radius array against single loop coil. In the area of Misalignment tangential boundary, efficiency increased by 5-10% compared to circular coil arrays. The proposed novel coil series achieves a higher overall PTE than a single coil design and an increase in PTE in the tangential boundary misalignment when compared to circular coil arrays

Model of Radio Managing System for Electro Vehicles’ Accumulators Wireless Feeding

This article refers to studying of the system for wireless feeding of electro vehicles’ accumulators, and the description of it’s applicable efficiency. Preliminary design of the radio managing system is done. The electro vehicle feeding system is calculated for the freeway. By using LabVIEW program package model of radio managing system was designed

Three-phase magnetic field tested in wireless power transfer system

This paper presents a magnetic field three dimensional mapping produced by a threephase prototype for wireless power transfer. The presented magnetic field mapping is a contribution to improve the design of electric vehicles battery chargers using the wireless power transfer. To collect the magnetic field data, a prototype was built, in order to support the tests. The prototype primary is an electrical three-phase system that allows to be connected electrically and geometrically in star or delta. The losses due to the magnetic field dispersion and the generated interferences in the surrounding equipment or in human body are discussed. The different standards organizations related to electric vehicles battery chargers are presented. Finally the magnetic field influence on the human body is addressed

Inductive Wireless Power Transfer Charging for Electric vehicles - A Review

Considering a future scenario in which a driverless Electric Vehicle (EV) needs an automatic charging system without human intervention. In this regard, there is a requirement for a fully automatable, fast, safe, cost-effective, and reliable charging infrastructure that provides a profitable business model and fast adoption in the electrified transportation systems. These qualities can be comprehended through wireless charging systems. Wireless Power Transfer (WPT) is a futuristic technology with the advantage of flexibility, convenience, safety, and the capability of becoming fully automated. In WPT methods resonant inductive wireless charging has to gain more attention compared to other wireless power transfer methods due to high efficiency and easy maintenance. This literature presents a review of the status of Resonant Inductive Wireless Power Transfer Charging technology also highlighting the present status and its future of the wireless EV market. First, the paper delivers a brief history throw lights on wireless charging methods, highlighting the pros and cons. Then, the paper aids a comparative review of different type’s inductive pads, rails, and compensations technologies done so far. The static and dynamic charging techniques and their characteristics are also illustrated. The role and importance of power electronics and converter types used in various applications are discussed. The batteries and their management systems as well as various problems involved in WPT are also addressed. Different trades like cyber security economic effects, health and safety, foreign object detection, and the effect and impact on the distribution grid are explored. Prospects and challenges involved in wireless charging systems are also highlighting in this work. We believe that this work could help further the research and development of WPT systems.publishedVersio