Special Issue "Selected Papers from The 31st International Electric Vehicles Symposium and Exhibition (Kobe, Japan)"

A special issue of World Electric Vehicle Journal (ISSN 2032-6653).

Deadline for manuscript submissions: closed (19 April 2019).

Special Issue Editors

Dr. Hiroshi Fujimoto
Website
Guest Editor
Department of Advanced Energy, Graduate School of Frontier Sciences, Room 3A7, Transdisciplinary Sciences building, 5-1-5 Kashiwanosha, Kashiwa, Chiba 277-8561, Japan
Interests: Electric vehicle motion control; In-wheel motor; Wireless power transfer
Prof. Dr. Joeri Van Mierlo
Website
Co-Guest Editor
Mr. Kenji Morita
Website
Co-Guest Editor
E-mobility Research Division, Japan Automobile Research, Institute, 1-1-30, Shibadaimon, Minato-ku, Tokyo 105-0012, Japan
Interests: Electrically propelled vehicles in general; CO2 reduction; Battery; Evaluation test method

Special Issue Information

Dear Colleagues,

This Special Issue gathers updated versions of a selection of best papers from EVS31 — the 31th International Electric Vehicle Symposium and Exhibition & International Electric Vehicle Technology Conference, which was organized from 30 September to 3 October 2018 in Kobe, Japan.

EVS is the leading international event to address all these issues on e-mobility. The various components of electric mobility were on display; from markets to vehicle battery technology; from motorcycles to trucks, and from charging facilities to related services and public policy.

The authors of the best papers presented at EVS31 were invited to further extend their EVS31 paper, including their most recent research findings. After a second thorough round of peer review, these papers will be published in this Special Issue of the World Electric Vehicle Journal, WEVJ. The Article Processing Charges (APC) for those selected papers will be fully waived.

If you want to know more about the World Electric Vehicle Journal, feel free to read the Editorial at https://www.mdpi.com/2032-6653/9/1/1.

The hosts of EVS31 were the World Electric Vehicle Association (WEVA) and Electric Vehicle Association of Asia Pacific (EVAAP). Japan Automobile Research Institute (JARI) and Society of Automotive Engineers of Japan (JSAE) were organizing the event with the collaboration of The European Association for Electromobility (AVERE) and Electric Drive Transportation Association (EDTA).

Dr. Hiroshi Fujimoto
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. World Electric Vehicle Journal is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. As selected papers, the original 300 CHF Article Processing Charge (APC) for publication will be paid by AVERE. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (25 papers)

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Research

Open AccessArticle
The Parker Project: Cross-Brand Service Testing Using V2G
World Electr. Veh. J. 2019, 10(4), 66; https://doi.org/10.3390/wevj10040066 - 26 Oct 2019
Abstract
The Parker project sought to experimentally validate that contemporary series-produced electric vehicles (EVs), capable of V2G, are ready to participate in a number of advanced grid services. In such services, the timing, size and direction of power and energy exchanged between the EV [...] Read more.
The Parker project sought to experimentally validate that contemporary series-produced electric vehicles (EVs), capable of V2G, are ready to participate in a number of advanced grid services. In such services, the timing, size and direction of power and energy exchanged between the EV battery and grid is controlled as to support either a single building, the local neighborhood or the regional power system. Vehicles purposely designed for such services are referred to as grid integrated electric vehicles (GIVs). The field of research, describing how GIVs may be used to actively support the power system, is called Vehicle–Grid Integration (VGI). The purpose of this paper is to present how the Danish Parker project has systematically categorized a range of grid services, collected in a service catalog, and then illustrate state-of-the-art EVs ability to support such services through experimental validation. Results are presented for three different tests performed in Parker; marginal emission factor charging, frequency containment reserves and a performance test for controlling power setpoints. The ultimate aim of this paper, and the Parker project, is to promote the GIV concept so that it may inform the design and capabilities of present and future EVs, EV supply equipment (EVSE) and communication standards. Full article
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Open AccessArticle
Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor
World Electr. Veh. J. 2019, 10(4), 62; https://doi.org/10.3390/wevj10040062 - 05 Oct 2019
Cited by 1
Abstract
In order to solve the problems of wear and spark of the brush and slip ring in an electrically excited synchronous motor (EESM), based on the principle of magnetic resonance coupling wireless power transfer (MRC-WPT), a resonant wireless excitation system of EESM is [...] Read more.
In order to solve the problems of wear and spark of the brush and slip ring in an electrically excited synchronous motor (EESM), based on the principle of magnetic resonance coupling wireless power transfer (MRC-WPT), a resonant wireless excitation system of EESM is designed. By modeling the EESM and analyzing the rotor field oriented control (RFOC) method, a control system of the resonant wireless EESM (RW-EESM) is established. Furthermore, the stator current distribution strategy is analyzed. Finally, a test of the RE-EESM prototype is carried out. The test results show that the motor can realize no-load stable operation, and the test speed is maintained at 85 r/min. The results show that the wireless excitation scheme of EESM is feasible, and the RFOC of RW-EESM motor is reasonable. Full article
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Open AccessArticle
A Real-Car Experiment of a Dynamic Wireless Power Transfer System Based on Parallel-Series Resonant Topology
World Electr. Veh. J. 2019, 10(3), 49; https://doi.org/10.3390/wevj10030049 - 20 Jul 2019
Abstract
A short mileage and long charging times are problems facing electric vehicles (EVs), and dynamic wireless power transfer (WPT) systems are one of the most effective solutions to overcome these shortcomings. This paper proposes a dynamic WPT system consisting of several stationary primary [...] Read more.
A short mileage and long charging times are problems facing electric vehicles (EVs), and dynamic wireless power transfer (WPT) systems are one of the most effective solutions to overcome these shortcomings. This paper proposes a dynamic WPT system consisting of several stationary primary underground coils and a secondary coil on an EV. The dynamic WPT system employed solenoid coils that were superior to circular coils in terms of misalignment to the traveling direction. A dynamic WPT system rated at 25 kW was designed, constructed, and tested to verify the principles of operation; that is, the capability of supplying electric power continuously. Full article
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Open AccessArticle
Development of Technical Regulations for Fuel Cell Motorcycles in Japan—Hydrogen Safety
World Electr. Veh. J. 2019, 10(3), 48; https://doi.org/10.3390/wevj10030048 - 09 Jul 2019
Abstract
Hydrogen fuel cell vehicles are expected to play an important role in the future and thus have improved significantly over the past years. Hydrogen fuel cell motorcycles with a small container for compressed hydrogen gas have been developed in Japan along with related [...] Read more.
Hydrogen fuel cell vehicles are expected to play an important role in the future and thus have improved significantly over the past years. Hydrogen fuel cell motorcycles with a small container for compressed hydrogen gas have been developed in Japan along with related regulations. As a result, national regulations have been established in Japan after discussions with Japanese motorcycle companies, stakeholders, and experts. The concept of Japanese regulations was proposed internationally, and a new international regulation on hydrogen-fueled motorcycles incorporating compressed hydrogen storage systems based on this concept are also established as United Nations Regulation No. 146. In this paper, several technical regulations on hydrogen safety specific to fuel cell motorcycles incorporating compressed hydrogen storage systems are summarized. The unique characteristics of these motorcycles, e.g., small body, light weight, and tendency to overturn easily, are considered in these regulations. Full article
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Open AccessArticle
Case Study of Holistic Energy Management Using Genetic Algorithms in a Sliding Window Approach
World Electr. Veh. J. 2019, 10(2), 46; https://doi.org/10.3390/wevj10020046 - 18 Jun 2019
Abstract
Energy management systems are used to find a compromise between conflicting goals that can be identified for battery electric vehicles. Typically, these are the powertrain efficiency, the comfort of the driver, the driving dynamics, and the component aging. This paper introduces an optimization-based [...] Read more.
Energy management systems are used to find a compromise between conflicting goals that can be identified for battery electric vehicles. Typically, these are the powertrain efficiency, the comfort of the driver, the driving dynamics, and the component aging. This paper introduces an optimization-based holistic energy management system for a battery electric vehicle. The energy management system can adapt the vehicle velocity and the power used for cabin heating, in order to minimize the overall energy consumption, while keeping the total driving time and the cabin temperature within predefined limits. A genetic algorithm is implemented in this paper. The approach is applied to different driving cycles, which are optimized by dividing them into distinctive time frames. This approach is referred to as the sliding window approach. The optimization is conducted with two separate driving cycles, the New European Driving Cycle (NEDC) and a recorded real-world drive. These are analyzed with regard to the aspects relevant to the energy management system, and the optimization results for the two cycles are compared. The results presented in this paper demonstrate the feasibility of the sliding window approach. Moreover, they reveal the differences in fundamental parameters between the NEDC and the recorded drive and how they affect the optimization results. The optimization leads to an overall reduction in energy consumption of 3.37 % for the NEDC and 3.27 % for the recorded drive, without extending the travel time. Full article
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Open AccessArticle
Electric Vehicle Fast Charging Needs in Cities and along Corridors
World Electr. Veh. J. 2019, 10(2), 45; https://doi.org/10.3390/wevj10020045 - 18 Jun 2019
Cited by 3
Abstract
Fast charging is seen as a means to facilitate long-distance driving for electric vehicles (EVs). As a result, roll-out planning generally takes a corridor approach. However, with higher penetration of electric vehicles in urban areas, cities contemplate whether inner-city fast chargers can be [...] Read more.
Fast charging is seen as a means to facilitate long-distance driving for electric vehicles (EVs). As a result, roll-out planning generally takes a corridor approach. However, with higher penetration of electric vehicles in urban areas, cities contemplate whether inner-city fast chargers can be an alternative for the growing amount of slow public chargers. For this purpose, more knowledge is required in motives and preferences of users and actual usage patterns of fast chargers. Similarly, with increasing charging speeds of fast chargers and different modes (taxi, car sharing) also switching to electric vehicles, the effect of charging speed should be evaluated as well as preferences amongst different user groups. This research investigates the different intentions and motivations of EV drivers at fast charging stations to see how charging behaviour at such stations differs using both data analysis from charging stations as a survey among EV drivers. Additionally, it estimates the willingness of EV drivers to use fast charging as a substitute for on-street home charging given higher charging speeds. The paper concludes that limited charging speeds imply that EV drivers prefer parking and charging over fast charging but this could change if battery developments allow higher charging speeds. Full article
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Open AccessArticle
Battery Sizing for Electric Vehicles Based on Real Driving Patterns in Thailand
World Electr. Veh. J. 2019, 10(2), 43; https://doi.org/10.3390/wevj10020043 - 15 Jun 2019
Abstract
The rising population in suburban areas have led to an increasing demand for commuter buses. Coupled with a desire to reduce pollution from the daily routine of traveling and transportation, electric vehicles have become more interesting as an alternative placement for internal combustion [...] Read more.
The rising population in suburban areas have led to an increasing demand for commuter buses. Coupled with a desire to reduce pollution from the daily routine of traveling and transportation, electric vehicles have become more interesting as an alternative placement for internal combustion engine vehicles. However, in comparison to those conventional vehicles, electric vehicles have an issue of limited driving range. One of the main challenges in designing electric vehicles (EVs) is to estimate the size and power of energy storage system, i.e., battery pack, for any specific application. Reliable information on energy consumption of vehicle of interest is therefore necessary for a successful EV implementation in terms of both performance and cost. However, energy consumption usually depends on several factors such as traffic conditions, driving cycle, velocities, road topology, etc. This paper presents an energy consumption analysis of electric vehicle in three different route types i.e., closed-area, inter-city, and local feeder operated by campus tram and shuttle bus. The driving data of NGV campus trams operating in a university located in suburban Bangkok and that of shuttle buses operating between local areas and en route to the city were collected and the corresponding representative driving cycles for each route were generated. The purpose of this study was to carry out a battery sizing based on the fulfilment of power requirements from the representative real driving pattern in Thailand. The real driving cycle data i.e., velocity and vehicle global position were collected through a GPS-based piece of equipment, VBOX. Three campus driving data types were gathered to achieve a suitable dimensioning of battery systems for electrified university public buses. Full article
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Open AccessArticle
Simulation of Future Electric Vehicle Charging Behavior—Effects of Transition from PHEV to FEV
World Electr. Veh. J. 2019, 10(2), 42; https://doi.org/10.3390/wevj10020042 - 14 Jun 2019
Cited by 2
Abstract
The Netherlands is a frontrunner in the field of public charging infrastructure, having one of the highest number of public charging stations per electric vehicle (EV) in the world. During the early years of adoption (2012–2015), a large percentage of the EV fleet [...] Read more.
The Netherlands is a frontrunner in the field of public charging infrastructure, having one of the highest number of public charging stations per electric vehicle (EV) in the world. During the early years of adoption (2012–2015), a large percentage of the EV fleet were plugin hybrid electric vehicles (PHEV) due to the subsidy scheme at that time. With an increasing number of full electric vehicles (FEVs) on the market and a current subsidy scheme for FEVs only, a transition of the EV fleet from PHEV to FEV is expected. This is hypothesized to have an effect on the charging behavior of the complete fleet, and is reason to understand better how PHEVs and FEVs differ in charging behavior and how this impacts charging infrastructure usage. In this paper, the effects of the transition of PHEV to FEV is simulated by extending an existing agent-based model. Results show important effects of this transition on charging infrastructure performance. Full article
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Open AccessArticle
Evaluation of the Magnetic Field Leakage from Two Wireless Power Transfer Systems for EV/PHV Driven Simultaneously
World Electr. Veh. J. 2019, 10(2), 41; https://doi.org/10.3390/wevj10020041 - 13 Jun 2019
Abstract
Wireless power transfer for electric and plug-in hybrid vehicles has been developed to facilitate battery charging. In a wireless power transfer system, because the magnetic field leaks to the surroundings of the vehicle, it is important to evaluate the quantitative human exposure. The [...] Read more.
Wireless power transfer for electric and plug-in hybrid vehicles has been developed to facilitate battery charging. In a wireless power transfer system, because the magnetic field leaks to the surroundings of the vehicle, it is important to evaluate the quantitative human exposure. The International Commission on Non-Ionizing Radiation Protection provides guidelines for human exposure assessment. In this study, we evaluate the magnetic field leakage under two parking configurations and current phase differences for two vehicles being simultaneously charged (3.7 kW at 85 kHz per vehicle). The results of the analysis show that the magnetic field leakage is lower than the reference level of the guidelines for all cases and that the leakage could be reduced by controlling the phase difference between the two wireless power transfer systems equally distributed from the single high-frequency power source for each parking configuration. Full article
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Open AccessArticle
Comparative Verification of Radiation Noise Reduction Effect Using Spread Spectrum for Inductive Power Transfer System
World Electr. Veh. J. 2019, 10(2), 40; https://doi.org/10.3390/wevj10020040 - 10 Jun 2019
Abstract
This paper provides a comparative study on radiation noise reduction methods for inductive power transfer systems using spread spectrum. In the spread spectrum methods, the radiation noise is reduced by continuously changing an output frequency of the inverter according to pseudorandom numbers. The [...] Read more.
This paper provides a comparative study on radiation noise reduction methods for inductive power transfer systems using spread spectrum. In the spread spectrum methods, the radiation noise is reduced by continuously changing an output frequency of the inverter according to pseudorandom numbers. The effects of the radiation noise reduction are evaluated with the inductive power transfer (IPT) system with series-parallel compensation and series-series compensation. The results show that the peak values of the radiation noise around the fundamental frequency are reduced by 7.8 and 8.1 dBμA in maximum with the series-series compensation method and the series-parallel compensation method, respectively in comparison with the constant frequency operation. From these results, the proposed methods are effective for both the series-series compensation and series-parallel compensation method. Moreover, the efficiency of the IPT system with spread spectrum method is evaluated. The maximum DC-to-DC efficiency with the spread spectrum is 94.1% and 92.0% with the series-series compensation and the series-parallel compensation, respectively. Full article
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Open AccessArticle
Newly Developed Motor Cooling Method Using Refrigerant
World Electr. Veh. J. 2019, 10(2), 38; https://doi.org/10.3390/wevj10020038 - 04 Jun 2019
Abstract
One of the greatest issues for electric vehicles such as an electric vehicle (EV), a hybrid vehicle (HV), a plug-in hybrid electric vehicle (PHEV) and a fuel cell vehicle (FCV) is further improvement of effective motor cooling, since higher rated torque is achieved [...] Read more.
One of the greatest issues for electric vehicles such as an electric vehicle (EV), a hybrid vehicle (HV), a plug-in hybrid electric vehicle (PHEV) and a fuel cell vehicle (FCV) is further improvement of effective motor cooling, since higher rated torque is achieved with higher cooling performance. In this paper, we introduce and propose a newly developed motor cooling method we tested using refrigerant, comparing with conventional water cooling. Test results show higher cooling performance of refrigerant cooling, which achieved the rated torque 60% higher than that of water cooling. Full article
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Open AccessArticle
Stand-Alone Battery Thermal Management for Fast Charging of Electric Two Wheelers—Integrated Busbar Cooling
World Electr. Veh. J. 2019, 10(2), 37; https://doi.org/10.3390/wevj10020037 - 04 Jun 2019
Abstract
This paper presents a thermal interface for cylindrical cells using busbar-integrated cooling channels. This interface is available due to the use of a stand-alone refrigerant circuit for the thermal management of the battery. A stand-alone refrigerant circuit offers performance and efficiency increases compared [...] Read more.
This paper presents a thermal interface for cylindrical cells using busbar-integrated cooling channels. This interface is available due to the use of a stand-alone refrigerant circuit for the thermal management of the battery. A stand-alone refrigerant circuit offers performance and efficiency increases compared to state-of-the-art battery thermal management systems. This can be achieved by increasing the evaporation temperature to the requirements of the Li-ion cells and the use of alternative refrigerants. The solution proposed in this paper is defined for electric two-wheelers, as the thermal management of these vehicles is currently insufficient for fast charging where high heat losses occur. Three channel patterns for the integrated busbar cooling were examined regarding their thermal performance to cool the li-ion cells of a 16p14s battery pack during fast charging. A method of coupling correlation-based heat transfer and pressure drop with thermal finite element method (FEM) simulations was developed. The symmetric channel pattern offers a good compromise between battery temperatures and homogeneity, as well as the best volumetric and gravimetric energy densities on system level. Average cell temperatures of 22 °C with a maximum temperature spread of 8 K were achieved. Full article
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Open AccessArticle
Ride Blending Control for Electric Vehicles
World Electr. Veh. J. 2019, 10(2), 36; https://doi.org/10.3390/wevj10020036 - 31 May 2019
Cited by 1
Abstract
Vehicles equipped with in-wheel motors (IWMs) feature advanced control functions that allow for enhanced vehicle dynamics and stability. However, these improvements occur to the detriment of ride comfort due to the increased unsprung mass. This study investigates the driving comfort enhancement in electric [...] Read more.
Vehicles equipped with in-wheel motors (IWMs) feature advanced control functions that allow for enhanced vehicle dynamics and stability. However, these improvements occur to the detriment of ride comfort due to the increased unsprung mass. This study investigates the driving comfort enhancement in electric vehicles that can be achieved through blended control of IWMs and active suspensions (ASs). The term “ride blending”, coined in a previous authors’ work and herein retained, is proposed by analogy with the brake blending to identify the blended action of IWMs and ASs. In the present work, the superior performance of the ride blending control is demonstrated against several driving manoeuvres typically used for the evaluation of the ride quality. The effectiveness of the proposed ride blending control is confirmed by the improved key performance indexes associated with driving comfort and active safety. The simulation results refer to the comparison of the conventional sport utility vehicle (SUV) equipped with a passive suspension system and its electric version provided with ride blending control. The simulation analysis is conducted with an experimentally validated vehicle model in CarMaker® and MATLAB/Simulink co-simulation environment including high-fidelity vehicle subsystems models. Full article
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Open AccessArticle
Electrical Steels and Their Evaluation for Automobile Motors
World Electr. Veh. J. 2019, 10(2), 31; https://doi.org/10.3390/wevj10020031 - 27 May 2019
Cited by 1
Abstract
Achieving high efficiency and high torque is an important target in EV motors. This paper describes the effect of the magnetic properties of electrical steels used as core materials for synchronous motors with permanent magnets, which are commonly used as the EV traction [...] Read more.
Achieving high efficiency and high torque is an important target in EV motors. This paper describes the effect of the magnetic properties of electrical steels used as core materials for synchronous motors with permanent magnets, which are commonly used as the EV traction motors. It was confirmed that electrical steels, which have high flux density and low iron loss properties can realize high motor efficiency and torque. When PWM excitation is considered, thinner electrical steels are advantageous to suppress increased loss due to higher harmonics. Based on these results, electrical steels having high flux densities and low iron losses at high frequencies were developed. Full article
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Open AccessArticle
Electric Safety Challenges with a Conductive Electric Road System—Chassis Potential Modeling and Measurement
World Electr. Veh. J. 2019, 10(2), 30; https://doi.org/10.3390/wevj10020030 - 24 May 2019
Abstract
Conductive Electric Road Systems (ERS) appear as a promising solution for the electrification of transportation, particularly for heavy vehicles and long-distance trips but also for light vehicles. Significant research efforts are currently devoted to the development of conductive ERS systems, with up to [...] Read more.
Conductive Electric Road Systems (ERS) appear as a promising solution for the electrification of transportation, particularly for heavy vehicles and long-distance trips but also for light vehicles. Significant research efforts are currently devoted to the development of conductive ERS systems, with up to four pilot test sites with different technologies in operation only in Sweden. With the help of electric models and experimental measurements on a pilot test track, this article assesses the potential safety challenges associated with one aspect of this technology: the absence of a reliable protective earth connection while the vehicle is connected to the ERS power supply. The results highlight the importance of monitoring the chassis potential at all times and the need of an active safety mechanism to disconnect the vehicle from the ERS supply if a severe fault occurs. Full article
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Open AccessArticle
Implementation of an Energy Management Strategy with Drivability Constraints for a Dual-Motor Electric Vehicle
World Electr. Veh. J. 2019, 10(2), 28; https://doi.org/10.3390/wevj10020028 - 23 May 2019
Abstract
This paper presents a real-time energy management strategy to distribute the power demand between two independent motors properly. Based on the characteristics of the novel transmission system, an enumeration-based searching approach is used to hunt for the optimal working points for both motors [...] Read more.
This paper presents a real-time energy management strategy to distribute the power demand between two independent motors properly. Based on the characteristics of the novel transmission system, an enumeration-based searching approach is used to hunt for the optimal working points for both motors to maximize the overall efficiency. Like many energy management strategies, approaches that focus on reducing energy consumption can result in frequent gearshifts. To improve drivability and make a balance between energy consumption and gearshifts, a cost function is designed. To verify the effectiveness of the proposed method, a mathematical model is built, and the simulation results demonstrate the achieved improvements. Full article
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Open AccessArticle
85 kHz Band 44 kW Wireless Rapid Charging System for Field Test and Public Road Operation of Electric Bus
World Electr. Veh. J. 2019, 10(2), 26; https://doi.org/10.3390/wevj10020026 - 23 May 2019
Cited by 1
Abstract
Wireless charging technology for heavy-duty vehicles has been investigated for eco-friendly transportation. We present a new wireless power transfer system for 44 kW rapid charging of electric buses. The transmission distance between the charging pads is from 10 to 13 cm. The large [...] Read more.
Wireless charging technology for heavy-duty vehicles has been investigated for eco-friendly transportation. We present a new wireless power transfer system for 44 kW rapid charging of electric buses. The transmission distance between the charging pads is from 10 to 13 cm. The large air gap can be fulfilled by the ordinary kneeling function, equipped on most low-floor buses. Dual-block parallel transmission with opposite-phase-current-feeding suppresses magnetic radiation. The system operates in the common 85 kHz band with the light-duty vehicle system. The result of the field test and the public road operation of two electric buses confirm the CO2 reduction effect described. Full article
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Open AccessArticle
Auxiliary Power Supply System for Electric Power Steering (EPS) and High-Heat-Resistant Lithium-Ion Capacitor
World Electr. Veh. J. 2019, 10(2), 27; https://doi.org/10.3390/wevj10020027 - 22 May 2019
Abstract
Advanced Driver Assistance System (ADAS) and Automated Driving (AD) are the two major topics for the current and next generations of vehicles. To realize them in full-size vehicles equipped with a 12 V power supply, the need for electric power steering (EPS) is [...] Read more.
Advanced Driver Assistance System (ADAS) and Automated Driving (AD) are the two major topics for the current and next generations of vehicles. To realize them in full-size vehicles equipped with a 12 V power supply, the need for electric power steering (EPS) is increasing. Currently, the steering system of full-size vehicles is equipped with hydraulic power steering due to electric power shortage. An auxiliary power supply system using a lithium-ion capacitor was developed in order to solve the concern. In addition, to mount the system in the vehicle with no cooling–heating equipment, development of expanding the operating temperature range of the lithium-ion capacitor was conducted. Several improvements have made the capacitor operate stably in high-temperature environments above 100 °C. Full article
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Open AccessArticle
Stabilization of Vehicle Dynamics by Tire Digital Control—Tire Disturbance Control Algorithm for an Electric Motor Drive System
World Electr. Veh. J. 2019, 10(2), 25; https://doi.org/10.3390/wevj10020025 - 21 May 2019
Abstract
We propose an algorithm with disturbance control for tires on electric vehicles (EVs) so as to improve the steering stability of the vehicle. The effect was validated on EVs equipped with twin independent electric motors on a skid pad. The algorithm with the [...] Read more.
We propose an algorithm with disturbance control for tires on electric vehicles (EVs) so as to improve the steering stability of the vehicle. The effect was validated on EVs equipped with twin independent electric motors on a skid pad. The algorithm with the disturbance controller can remove the external noise generated on tires in order to suppress the abrupt slip and micro vibration generated between the tire and road surface, especially on low friction surfaces at the critical speed of the vehicle. The effective frequency corresponded to tire scale length. The effect was verified by the fact that the hysteresis loop with control on the chart of steer angle and yaw rate showed a smaller loop than those without control. The hysteresis loop with control also appeared at the oversteering area, which can be interpreted as evidence that the algorithm can make the vehicle more stable and gain faster speed on the skid pad. It is concluded that the tire digital control works well without any information from sensors on the vehicle body and without any cooperative control between tires. Full article
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Open AccessArticle
Effects of Environmental Conditions on Cathode Degradation of Polymer Electrolyte Fuel Cell during Potential Cycle
World Electr. Veh. J. 2019, 10(2), 24; https://doi.org/10.3390/wevj10020024 - 21 May 2019
Abstract
We investigated the effects of cell temperature and the humidity of gas supplied to the cell during the load cycle durability test protocol recommended by The Fuel Cell Commercialization Conference of Japan (FCCJ). Changes in the electrochemically active surface area (ECA) and in [...] Read more.
We investigated the effects of cell temperature and the humidity of gas supplied to the cell during the load cycle durability test protocol recommended by The Fuel Cell Commercialization Conference of Japan (FCCJ). Changes in the electrochemically active surface area (ECA) and in the amount of carbon support corrosion were examined by using the JARI standard single cell. The ECA declined more quickly when the gas humidity was raised, and the carbon corrosion was at the same level. These results suggest that the agglomeration of platinum was accelerated by the same agglomeration mechanism, i.e., by raising the humidity of the gas supplied to the cell. Full article
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Open AccessArticle
Hardware Architecture and Configuration Parameters of a Low Weight Electronic Differential for Light Electric Vehicles with Two Independent Wheel Drive to Minimize Slippage
World Electr. Veh. J. 2019, 10(2), 23; https://doi.org/10.3390/wevj10020023 - 20 May 2019
Abstract
This article presents a design and performance analysis of an Electronic Differential (ED) system designed for Light Electric Vehicles (LEVs). We have developed a test tricycle vehicle with one front steering wheel and two rear fixed units in the same axis with a [...] Read more.
This article presents a design and performance analysis of an Electronic Differential (ED) system designed for Light Electric Vehicles (LEVs). We have developed a test tricycle vehicle with one front steering wheel and two rear fixed units in the same axis with a brushless DC (BLDC) motor integrated in each of them. Each motor has an independent controller unit and a common electronic Arduino CPU that can plan specific speeds for each wheel as curves are being traced. Different implementations of sensors (input current/torque, steering angle and speed of the wheels) are discussed related to their hardware complexity and performance based on speed level requirements and slipping on the traction wheels. Two driving circuits were generated (slalom and circular routes) and driven at different speeds, monitoring and recording all the related parameters of the vehicle. The most representative graphs obtained are presented. The analysis of these data presents a significant change of the behaviour of the control capability of the ED when the lineal speed of the vehicle makes a change of direction that passes 10 Km/h. In this situation, to obtain good performance of the ED, it is necessary to include sensors related to the wheels. Full article
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Open AccessArticle
Development of Hybrid Vehicle Energy Consumption Model for Transportation Applications—Part II: Traction Force-Speed Based Energy Consumption Modeling
World Electr. Veh. J. 2019, 10(2), 22; https://doi.org/10.3390/wevj10020022 - 09 May 2019
Cited by 1
Abstract
In the transportation sector, the fuel consumption model is a fundamental tool for vehicles’ energy consumption and emission analysis. Over the past decades, vehicle-specific power (VSP) has been enormously adopted in a number of studies to estimate vehicles’ instantaneous driving power. Then, the [...] Read more.
In the transportation sector, the fuel consumption model is a fundamental tool for vehicles’ energy consumption and emission analysis. Over the past decades, vehicle-specific power (VSP) has been enormously adopted in a number of studies to estimate vehicles’ instantaneous driving power. Then, the relationship between the driving power and fuel consumption is established as a fuel consumption model based on statistical approaches. This study proposes a new methodology to improve the conventional energy consumption modeling methods for hybrid vehicles. The content is organized into a two-paper series. Part I captures the driving power equation development and the coefficient calibration for a specific vehicle model or fleet. Part II focuses on hybrid vehicles’ energy consumption modeling, and utilizes the equation obtained in Part I to estimate the driving power. Also, this paper has discovered that driving power is not the only primary factor that influences hybrid vehicles’ energy consumption. This study introduces a new approach by applying the fundamental of hybrid powertrain operation to reduce the errors and drawbacks of the conventional modeling methods. This study employs a new driving power estimation equation calibrated for the third generation Toyota Prius from Part I. Then, the Traction Force-Speed Based Fuel Consumption Model (TFS model) is proposed. The combination of these two processes provides a significant improvement in fuel consumption prediction error compared to the conventional VSP prediction method. The absolute maximum error was reduced from 57% to 23%, and more than 90% of the predictions fell inside the 95% confidential interval. These validation results were conducted based on real-world driving data. Furthermore, the results show that the proposed model captures the efficiency variation of the hybrid powertrain well due to the multi-operation mode transition throughout the variation of the driving conditions. This study also provides a supporting analysis indicating that the driving mode transition in hybrid vehicles significantly affects the energy consumption. Thus, it is necessary to consider these unique characteristics to the modeling process. Full article
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Open AccessArticle
Test and Modelling of Commercial V2G CHAdeMO Chargers to Assess the Suitability for Grid Services
World Electr. Veh. J. 2019, 10(2), 21; https://doi.org/10.3390/wevj10020021 - 24 Apr 2019
Cited by 4
Abstract
Aggregation and control of electric vehicles (EVs) via vehicle-to-grid (V2G) technologies is seen as a valid option for providing ancillary power system services. This work presents results from V2G-ready equipment tests and modelling. The technical capabilities of an EV connected to a commercial [...] Read more.
Aggregation and control of electric vehicles (EVs) via vehicle-to-grid (V2G) technologies is seen as a valid option for providing ancillary power system services. This work presents results from V2G-ready equipment tests and modelling. The technical capabilities of an EV connected to a commercial V2G charger are investigated when controlled either locally or remotely. The charger is characterized in terms of efficiency characteristics, activation time, response granularity, ramping-up/down time, accuracy and precision. Test results show the performance for different operating conditions, highlighting the importance of a good calibration and knowledge of the employed hardware when providing standard-compliant grid regulation services via V2G technology. Ultimately, a set of simulations demonstrates that the designed EV charger model replicates accurately the operating conditions of the real hardware. Full article
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Open AccessArticle
A Comparison of Internal and External Preheat Methods for NMC Batteries
World Electr. Veh. J. 2019, 10(2), 18; https://doi.org/10.3390/wevj10020018 - 15 Apr 2019
Cited by 2
Abstract
Lithium-ion batteries (LiBs) performance can be significantly declined when operated at cold climates in terms of capacity loss, resistance increase and accelerated aging rates. To prevent this downgrade and to maintain the optimal operation of battery cells, a preheat process is taking place, [...] Read more.
Lithium-ion batteries (LiBs) performance can be significantly declined when operated at cold climates in terms of capacity loss, resistance increase and accelerated aging rates. To prevent this downgrade and to maintain the optimal operation of battery cells, a preheat process is taking place, which can be implemented either by internal or external techniques. The former is performed actively, by circulating a constant amplitude and frequency alternative pulse current (APC) at the battery cell’s terminal and preheating it internally by harvesting its generated Joule losses. The latter is achieved passively, by enclosing the cell into thermal blankets. In this work, a comparison of these two preheating strategies is presented, by proposing electro-thermal and lifetime models of a lithium nickel manganese cobalt oxide (NMC/G) 20 Ah pouch battery cell. Heat transfer, energy efficiencies and degradation costs are estimated during operation of the preheat techniques. Validation of the model showed a good agreement between the model and experimental data, and a study case is proposed to estimate and compare the cost efficiency of the methods as based for an economic study. Full article
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Open AccessArticle
Location-Allocation of Electric Vehicle Fast Chargers—Research and Practice
World Electr. Veh. J. 2019, 10(1), 12; https://doi.org/10.3390/wevj10010012 - 06 Mar 2019
Cited by 4
Abstract
This paper conducts a comparative analysis of academic research on location-allocation of electric vehicle fast chargers into the pattern of the actual fast-charger allocation in the United States. The work aims to highlight the gap between academic research and actual practice of charging-station [...] Read more.
This paper conducts a comparative analysis of academic research on location-allocation of electric vehicle fast chargers into the pattern of the actual fast-charger allocation in the United States. The work aims to highlight the gap between academic research and actual practice of charging-station placement and operation. It presents evidence that the node-serving approach is, in fact, applied in the actual location-allocation of fast charging stations. However, little evidence suggests that flow-capturing, which has been much more predominantly applied in research, is being applied in practice. The author argues that a large-scale location-allocation plan for public fast chargers should be formulated based on explicit consideration of stakeholders, the objective, practical constraints, and underlining assumptions. Full article
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