World Electr. Veh. J., Volume 11, Issue 1 (March 2020) – 28 articles

Aiming at the torque ripple problem of direct torque control that is based on space vector pulse width modulation (SVPWM-DTC) caused by the spatial harmonics and magnetic saturation characteristics of permanent magnet synchronous motor (PMSM), a feedforward controller based on an analytical model of PMSM was designed. An analytical motor model taking the spatial harmonics and magnetic saturation characteristics of PMSM into account by reconstructing the numerical solution of magnetic co-energy (MCE) from finite element analysis (FEA) was proposed. Based on that, the optimal stator flux linkage that minimizes the torque ripple is calculated and then a feedforward controller is designed and added to the SVPWM-DTC framework. Simulations and experiments are carried out and the results show that the proposed feedforward controller can effectively reduce the torque ripple of SVPWM-DTC. Full article

Discontinuous pulse width modulation (DPWM) strategies are usually adopted to reduce the switching loss and output current ripple of three-phase three-level traction inverters under three-phase load conditions. However, if there is a short circuit in any arbitrary phase or the inverter is used to feed a two-phase load, the output performance of conventional DPWM strategies will be deteriorated. Here, four improved DPWM (IDPWM) strategies for three-phase three-level neutral-point-clamped (NPC) traction inverter fed two-phase load are proposed. Unlike three-phase load conditions, the phase angle and the amplitude of each basic voltage vector in the space vector diagram are modified under two-phase load conditions. Consequently, sectors are re-divided and duty cycles of basic vectors during synthesis are recalculated. Clamping intervals of each phase for the four type discontinuous PWM (DPWM) strategies are rearranged according to the modified space vector diagram; then, the proposed DPWM strategies can be obtained. Compared with the conventional DPWM strategies, the output current waveform quality of the proposed strategy is significantly improved. Meanwhile, the amplitude of the neutral-point voltage ripple is also reduced. Full article

The present work focuses on an aerodynamic and heat transfer study of a battery powered vehicle moving in a vacuum tunnel. The conducted research was based on analytical analysis and numerical calculations. Four different vacuum levels in the tunnel were considered—100 Pa, 1 kPa, 10 kPa and 100 kPa—and two distinct velocities of the vehicle—125 and 166 m/s—to address subsonic and supersonic conditions. It allowed defining limitations related to vacuum transportation in terms of velocity of the vehicle and a blocking ratio of the tunnel. Power consumption and drag coefficient for the considered tunnel pressures were analyzed. The cooling analysis of the batteries by passing air was performed numerically and analytically in the function of flow conditions in the tunnel. It gave some insight into main problems related to cooling of the batteries under low pressure and possible directions to solve it. It was shown that the proposed analytical model compared satisfactorily with the numerical results. Full article

A Finite Element (FE) modelling approach is presented to account for the core losses in electrical machines that are generated by higher harmonic frequencies, for example those caused by Pulse Width Modulation (PWM) switching or by space harmonics due to the machine geometry. The model builds further on a post-processing calculation tool that was recently developed to take into account the magnetic skin effect in electrical steel laminations at high frequencies, and extends this by a more detailed loss analysis of the minor hysteresis loops that are caused by the higher harmonics. Further, these tools for high-frequency loss analysis are integrated into a complete electrical machine model with separate consideration of the major and minor loops. The modelling approach relies strongly on extensive magnetic measurement data of the electrical steel, in order to accurately predict the different loss components for minor hysteresis loops as a function of the DC bias field, frequency and amplitude of the minor loop. Results from the model are shown for an automotive traction motor, illustrating the losses caused by PWM harmonics and demonstrating the relevance of including the skin effect in these calculations. Full article

Battery technology has been one of the bottlenecks in electric cars. Whether it is in theory or in practice, the research on battery management is extremely important, especially for battery state-of-charge estimation. In fact, the battery has a strong time-varying and non-linear properties, which are extremely complex. Therefore, accurately estimating the state of charge is a challenging task. This paper reviews various representative patents and papers related to the state of charge estimation methods for an electric vehicle battery. According to their theoretical and experimental characteristics, the estimation methods were classified into three groups: the traditional methods based on the battery experiments, the modern methods based on control theory, and other methods based on the innovative ideas, especially focusing on the algorithms based on control theory. The results imply that the algorithms based on control theory, especially intelligent algorithms, are the focus of research in this field. The future development direction is to establish a rich database, improve hardware technology, come up with a much better battery model, and give full play to the advantages of each algorithm. Full article

The paper investigates whether it makes economic sense to use electric vehicles (EVs) in the public sector fleet. Thanks to the data collected in 2018 in 77 public sector entities in an Italian region, Friuli Venezia Giulia, we compare the total cost of ownership of a battery electric vehicle with that of a similar internal combustion engine one. We provide estimates for four scenarios (status quo, social cost internalization, price discounts and a combination of the last two) for three groups of public entities (local health authorities, municipalities and special purpose authorities) regarding passenger cars and mixed-use small light commercial vehicles. We find that, with the current price and cost structure, it makes economic sense to adopt EVs for a positive although relatively small percentage of the public sector fleet. Full article

A smart charging profile was implemented on 39 public charging stations in Amsterdam on which the current level available for electric vehicle (EV) charging was limited during peak hours on the electricity grid (07:00–08:30 and 17:00–20:00) and was increased during the rest of the day. The impact of this profile was measured on three indicators: average charging power, amount of transferred energy and share of positively and negatively affected sessions. The results are distinguished for different categories of electric vehicles with different charging characteristics (number of phases and maximum current). The results depend heavily on this categorisation and are a realistic measurement of the impact of smart charging under real world conditions. The average charging power increased as a result of the new profile and a reduction in the amount of transferred energy was detected during the evening hours, causing outstanding demand which was solved at an accelerated rate after limitations were lifted. For the whole population, 4% of the sessions were positively affected (charged a larger volume of energy) and 5% were negatively affected. These numbers are dominated by the large share of plug-in hybrid electric vehicles (PHEVs) in Amsterdam which are technically not able to profit from the higher current levels. For new generation electric vehicles, 14% of the sessions were positively affected and the percentage of negatively affected sessions was 5%. Full article

Electrification of mobility exceeds personal transport to increasingly focus on particular segments such as city logistics and taxis. These commercial mobility segments have different motives to purchase a full electric vehicle and require a particular approach to incentivize and facilitate the transition towards electric mobility. A case where a municipality was successful in stimulating the transition to electric mobility is the taxi sector in the city of Amsterdam. Using results from a survey study (n = 300), this paper analyses the differences in characteristics between taxi drivers that either have or do not have interest in purchasing a full electric taxi vehicle. Results show a low intention across the sample to adopt a full electric vehicle and no statistically significant differences in demographics between the two groups. Differences were found between the level of acceptability of the covenant, the rated attractiveness of the incentives, the ratings of full electric vehicle attributes and the consultation of objective and social information sources. These results can be used by policy makers to develop new incentives that target specific topics currently influencing the interest in a full electric taxi vehicle. Full article

Electric vehicles (EVs) include battery electric vehicles (BEVs), fuel-cell vehicles (FCVs) and fuel-cell hybrid electric vehicles (FCHEVs). The performance of vehicles is usually evaluated using standardized driving cycle tests; however, the results from standardized driving cycle tests deviate from the real-world driving cycle. In order to test the adaptability of EVs to real-world driving cycles, conditions of three typical routes in Tianjin are collected and their characteristics analyzed; then BEV and FCV models are created based on a type of FCHEV to simulate 0–100 km/h acceleration and cruising performance under a real-world driving cycle; finally, a motor bench is used to test the performance of FCHEV under the NEDC (New European Driving Cycle). After the adaptability of the three models to real-world driving cycle is compared based on the simulation and test results, it is found that FCHEV can recycle braking energy and has quick dynamic response, which can be well adapted to the real-world driving cycle. Full article

The improvement commercial competitiveness of private electric vehicles supported by the European policy for the decarbonisation of transport and with the consumers awareness-raising about CO₂ emissions and climate change, are driving the increase of electric vehicles on the roads. Therefore, public charging networks are facing the challenge of supply electricity to a fast increasing number of electric cars. The objective of this paper is to establish an assessment framework for analysis and monitor of existing charging networks. The developed methodology comprises modelling the charging infrastructure electricity profile, analysing the data by using machine learning models such as functional k-means clustering and defining a novel congestion metric. The described framework has been tested against Irish public charging network historical datasets. The analyses reveal a lack of reliability of the communication network infrastructure, frequent congestion events for commercial and shopping areas in specific clusters of charge points and the presence of power peaks caused by the high number of simultaneous charging events. Several recommendations for future network expansion have been highlighted. Full article

The aging of lithium-ion batteries (LIBs) is a crucial issue and must be investigated. The aging rate of LIBs depends not only on the material and electrochemical performance but also on the working conditions. In order to assess the impact of vehicle driving conditions, including the driving cycle, ambient temperature, charging mode, and trip distance on the battery life cycle, this paper first establishes an electric vehicle (EV) energy flow model to solve the operating parameters of the battery pack while working. Then, a powertrain test is carried out to verify the simulation model. Based on the simulated data under different conditions, the battery capacity fade process is estimated by using a semi-empirical aging model. The mileage (Ф) traveled by the vehicle before the end of life (EOL) of the battery pack is then calculated and taken as the evaluation index. The results indicate that the Ф is higher when the vehicle drives the Japanese chassis dynamometer test cycle JC08 than in the New European Driving Cycle (NEDC) and the Federal Test Procedure (FTP-75). The Ф will be dramatically reduced at both low and high ambient temperatures. Fast charging can increase the Ф at low ambient temperatures, whereas long trip driving can always increase Ф to varying degrees. Full article

Especially in urban areas, a large proportion of air pollution can be attributed to road traffic. Thus, in many countries, bans are being discussed on diesel vehicles in inner cities. These diesel bans pose a severe threat to logistics service providers (LSPs) that are active in city logistics, since their fleets are based on diesel-powered vehicles. One solution for LSPs is to introduce battery-electric heavy-duty trucks (HDTs). However, this is rarely done at present, due to high investment costs of such trucks. In order to compensate these high investments, high mileages are required in order to benefit from such vehicles’ low operating costs. Implementing 24-hour delivery would increase the daily mileage of HDTs. Because of noise emission regulations, 24-hour delivery could only be performed using battery-electric HDTs. In this study, we explore whether using battery-electric HDTs for 24-hour delivery is economical for LSPs. We use data from a German LSP in food logistics, develop a system dynamics model, and integrate a total cost of ownership calculation along with an LSP and a retail store discrete choice model to determine whether 24-hour delivery with battery-electric HDTs is profitable for the LSP, and how it might be accepted and diffused among stores. We find that 24-hour delivery using battery-electric HDTs is immediately profitable. This is due to the almost 50% increase in the daily trip potential of battery-electric HDTs in comparison to diesel HDTs, which leads to a lower required total number of HDTs in the fleet. Lower transportation costs, increased delivery quality, and decreased risk lead to rapid adoption of 24-hour delivery among stores, while lower total costs of ownership (TCO) accelerate the adoption by the LSP. Diffusion through the fleet and stores takes only slightly longer than one HDT lifetime. Consequently, 24-hour delivery with battery-electric HDTs is a promising solution for innovative and sustainable city logistics. Full article

In order to obtain a lightweight front upright of an electric formula car’s suspension, the topology optimization method is used in the front upright structure design. The mathematical model of the lightweight optimization design is constructed, and the geometric model of the initial design of the front upright is subjected to the ultimate load condition. The structural optimization of a front upright resulted in the mass reduction of the upright by 60.43%. The optimized model was simulated and verified regarding the strength, stiffness, and safety factor under three different conditions, namely turning braking, emergency braking, and sharp turning. In the experiment, the uprights were machined and assembled and integrated into the racing suspension. The experimental results showed that the optimized front uprights met the requirements of performance. Full article

The energy stored in electric vehicles (EVs) would be made available to commercial buildings to actively manage energy consumption and costs in the near future. These concepts known as vehicle-to-building (V2B) and vehicle-to-grid (V2G) technologies have the potential to provide storage capacity to benefit both EV and building owners respectively, by reducing some of the high cost of EVs, buildings’ energy cost, and providing reliable emergency backup services. In this study, we considered a vehicle-to-buildings/grid (V2B/V2G) system simultaneously for peak shaving and frequency regulation via a combined multi-objective optimization strategy which captures battery state of charge (SoC), EV battery degradation, EV driving scenarios, and operational constraints. Under these assumptions, we showed that the electricity usage/bill can be reduced by a difference of 0.1 on a scale of 0 to 1 (with 1 the normalized original electricity cost), and that EV batteries can also achieve superior economic benefits under controlled SoC limits (e.g., when kept between the SoC range of SoC_min > 30% and SoC_max < 90%) and subjected to very restricted charge-discharge battery cycling. Full article

The benefits of electrified powertrains for light-duty vehicles are well understood, however sufficient published information is not available on the benefits of advanced powertrains on the various types of medium and heavy duty vehicles. Quantifying the benefits of powertrain electrification will help fleet operators understand the advantages or limitations in adopting electrified powertrains in their truck fleets. Trucks vary in size and shape, as they are designed for specific applications. It is necessary to model each kind of truck separately to understand what kind of powertrain architecture will be feasible for their daily operations. This paper examines 11 types of vehicles and 5 powertrain technology choices to quantify the fuel saving potential of each design choice. This study uses the regulatory cycles proposed by the US Environmental Protection Agency (EPA) for measuring fuel consumption. Full article

This paper presents a gear shift method for the dual clutch transmission (DCT) with integrated electric motor in pure electric drive mode. In contrast to clutch-to-clutch shift in conventional DCT, a good gear shifting process relies on the coordinated control of the motor and synchronizer in electric drive mode of the hybrid DCT. To shorten the torque interruption time and reduce the wear of the synchronizer during engagement, the key point is to adjust the oncoming gear speed to the output shaft speed rapidly. This study provides a speed regulation control framework based on model predictive control (MPC) and disturbance observer (DO), where the MPC controller is designed to achieve a good tracking performance and the DO is to eliminate effects from exogenous disturbances. Simulation and experimental results demonstrate that the proposed approach can attain a rapid and robust gear shifting performance. Full article

Will automotive be the future of mobility or will the motorcar era come to an end in the 21st century? Today, auto-mobility is still growing, but in the future, this will depend on its ability to adapt to the needs of modern society. Disruptive technologies like electrification, automation, and connectivity can make automotive more sustainable by striving for the Six Zero goals: Zero Emission, Zero Energy, Zero Congestion, Zero Accident, Zero Empty, and Zero Cost. These tempting goals can lead not only to a more sustainable ecology, but also to a new economy with more efficient use of the time and money needed for mobility. In this future mobility framework, this article describes the practice-oriented research of the Rotterdam University of Applied Sciences with its regional partners to achieve these goals. Full article

Transportation system simulation is a widely accepted approach to evaluate the impact of transport policy deployment. In developing a transportation system deployment model, the energy impact of the model is extremely valuable for sustainability and validation. It is expected that different penetration levels of Connected-Autonomous Vehicles (CAVs) will impact travel behavior due to changes in potential factors such as congestion, miles traveled, etc. Along with such impact analyses, it is also important to further quantify the regional energy impact of CAV deployment under different factors of interest. The objective of this paper is to study the energy consumption of electrified vehicles in the future for different penetration levels of CAVs deployment in the City of Chicago. The paper will further provide a statistical analysis of the results to evaluate the impact of the different penetration levels on the different electrified powertrains used in the study. Full article

In this paper, optimization of Electric Vehicle (EV) batteries and dedicated energy storage unit charging profiles were conducted for the sake of bidding into day-ahead ancillary service markets. The aim of the optimization is to provide the maximum operational profits for both the EV aggregator and dedicated energy storage unit administrator. Ancillary service algorithms were then introduced to simulate the response of the EV batteries and dedicated energy storage units. Results showed that the usage of dedicated energy storage units for bidding into the ancillary services markets is more profitable than the case of operating an EV aggregator. Full article

Mobility as a Service (MaaS) is a concept that aligns with both current and future mobility demands of users, namely intermodal, personalized, on-demand and seamless. Although the number of shared mobility, electric mobility and multimodal passenger transport users is rapidly growing, until now, the list of MaaS and electric Mobility as Service (eMaaS) providers is quite short. This could partly be explained by the lack of a common architecture that facilitates the complex integration of all actors involved in the (e)MaaS ecosystem. The goal of this publication is to give an overview of the state of the art regarding (e)MaaS’ ecosystems and architectures. Moreover, it aims to support the further development of eMaaS by proposing a definition and a novel system architecture for eMaaS. Firstly, the state of the art of the MaaS ecosystem is reviewed. Secondly, the eMaaS ecosystem that builds upon our definition of eMaaS is described and the MaaS system- and technical- architectures found in literature are reviewed. Finally, an eMaaS architecture that focuses on the integration of MaaS and electric mobility systems is presented. With the definition, ecosystem and system architecture presented in this work, the aim is to support the further development of the eMaaS concept. Full article

Plug-in hybrid electric vehicles (PHEVs) are an effective intermediate vehicle technology option in the long-term transition pathway towards light-duty vehicle electrification. Their net environmental impact is evaluated using the performance metric Utility Factor (UF), which quantifies the fraction of vehicle miles traveled (VMT) on electricity. There are concerns about the gap between Environmental Protection Agency (EPA) sticker label and real-world UF due to the inability of test cycles to represent actual driving conditions and assumptions about their driving and charging differing from their actual usage patterns. Using multi-year longitudinal data from 153 PHEVs (11–53 miles all-electric range) in California, this paper systematically evaluates how observed driving and charging, energy consumption, and UF differs from sticker label expectations. Principal Components Analysis and regression model results indicated that UF of short-range PHEVs (less than 20-mile range) was lower than label expectations mainly due to higher annual VMT and high-speed driving. Long-distance travel and high-speed driving were the major reasons for the lower UF of longer-range PHEVs (at least 35-mile range) compared to label values. Enhancing charging infrastructure access at both home and away locations, and increasing the frequency of home charging, improves the UF of short-range and longer-range PHEVs respectively. Full article

This paper presents experiences from pilot-projects with battery-electric trucks in Norway, focusing on purchasing processes, technology, vehicle choices, user experience and various performance aspects. Furthermore, we discuss the electrification potential for battery-electric trucks and compare their total costs of ownership and associated socio-economic costs with internal combustion engine (ICE) trucks for a range of technological maturity scenarios. The results show that experiences have generally been positive but tailoring of use patterns is often required. Furthermore, at their current maturity level, battery-electric trucks could, to some extent, replace typical use of Norwegian ICE trucks, depending on the situation. In terms of costs, we expect that battery-electric light distribution trucks will first become competitive with ICE trucks when technology reaches mass production. Full article

In China, the development of pure electric buses is an essential means to address energy and environmental concerns. Proper evaluation and selection of pure electric buses is a crucial step prior to introducing the buses into actual operation. This paper presents a multi-objective method for the selection of pure electric buses based on road driving tests. An index system for evaluating the operating performance through the fuzzy analytic hierarchy process is established, and to ensure the method is more systematic than those in previous studies, indicators are classified into three categories: qualitative, semi-qualitative and quantitative indicators, of which the nineteen indexes have been comprehensively considered and designed. To verify the advantage of the evaluation method proposed in the article, two typical buses were selected as the assessed objectives regarding reliability, economic, security, environmental adaptability, etc. The assessing process indicates that the method is easily implemented and of high practical value. Additionally, the results show satisfactory agreement with the actual scenario. Thus, it can be assumed that the method detailed herein provides a basis for the design, selection, and evaluation of pure electric buses. Full article

The San Francisco Bay Area (Bay Area) leads the United States and California in the rate of electric vehicle (EV) adoption. However, EVs only represent 3% of vehicles driving on Bay Area roads. Widespread EV adoption requires that all Bay Area residents participate in the EV revolution regardless of demographics or geography. Equitable access to EVs will ensure that all Bay Area residents benefit from improved air quality, lower fuel and maintenance costs, and a better driving experience. Below, we delve into the unique EV market in the Bay Area and present information and insights from the Bay Area Air Quality Management District’s (Air District) EV programs. Full article

Electric vehicles are becoming more important in our society. Using them in a fleet to minimize energy cost is, therefore, a compelling opportunity for taxi companies. It is crucial to develop accurate models that estimate energy consumption for traveling from one point to another. Consumption can be estimated using a physical model, but such a model fails to fit real-world data, especially in taxi-driving conditions. We compare different approaches to learn from historical data in order to correct/improve the physical model. Similar techniques can be used to estimate consumption for a new vehicle model, which can be useful for companies that want to add a new vehicle model for which they do not have historical data. Full article

Responding to pressing problems arising from growing urban populations and mass motorization, municipalities need to take action. The resulting conditions include congested cities, poor air quality and quality of life. Providing contextual conditions and thereby increasing the amount of small electric vehicles could help reduce land use and improve air quality. Based on outcomes of expert interviews and an online survey, the status-quo of antecedences and barriers as well as potential measures for the implementation of small electric vehicles on a municipal level is outlined. To get an international and comprehensive view, experts from the USA, Asia and Europe participated. Results show that there are several obstacles that have to be overcome on local, national and international levels. For local policymakers especially, there is an array of measures available. The combination of push and pull measures is one key element. In this way, infrastructural changes, financial incentives, strategic implementations and soft measures to raise awareness could help the process of a market take-off immensely. Full article