•A methodology is proposed for selecting the best option for Pareto solutions.•Multi-objective optimization and multi-criteria decision-making methods are integrated.•The model provides an optimal ...electric vehicle supply equipment type at workplaces.•WASPAS model is improved by introducing Dombi Bonferroni functions for flexibility.
This study addresses the optimal planning of electric vehicle charging infrastructure at workplaces. As the optimal planning for a given workplace can involve various criteria that comprise conflicting single objectives, this study proposes a new integrated multi-objective optimization and multi-criteria decision-making (MCDM) model for determining the most suitable electric vehicle supply equipment (EVSE) configuration. This approach combines the advantage of multi-objective optimization, which yields Pareto solutions, with an improved MCDM model. The latter is used to evaluate the Pareto frontier to find the best performing solution by enabling the station owners to use linguistic variables for weighting the decision-making variables. The conventional weighted aggregated sum product assessment (WASPAS) method is improved by introducing the Dombi Bonferroni functions in the proposed model making it more flexible as compared to its counterparts. In the final step, the selected solutions are ranked by reapplying the MCDM model. A case study is performed based on collected charging data from a workplace. To validate the proposed model, a comparison against four alternative MCDM models is performed. It is demonstrated that the proposed model yields very close ranking order as the alternative approaches. Among five EVSE options, DC fast charging is found to be the best while AC Level-2 EVSE (19.2/22 kW) is found to be the least attractive option. Sensitivity analysis shows the robustness of the ranking results in response to changing weightings of the model coefficients.
As the transition to electric mobility accelerates, charging infrastructure is rapidly expanding. Publicly accessible chargers, also known as electric vehicle supply equipment (EVSE), are critical ...not only for further promoting the transition but also for mitigating charger access anxiety among electric vehicle (EV) users. It is essential to install the proper EVSE configuration that meets the EV user’s various considerations. This study presents a multi-criteria decision-making (MCDM) framework for determining the best performing public EVSE type from multiple EV user perspectives. The proposed approach combines a new MCDM model with an optimal public charging station model. While the optimal model outputs are used to evaluate the quantitative criteria, the MCDM model assesses EV users’ evaluations of the qualitative criteria using nonlinear Bonferroni functions extended by rough Dombi norms. The proposed MCDM has standardization parameters with a flexible rough boundary interval, allowing for flexible and rational decision-making. The model is tested using real public EVSE charging data and EV users’ evaluations from the field. All public EVSE alternatives are studied. Among the five EVSE options, DCFC EVSE is found to be the best performing, whereas three-phase AC L2 is the least performing option. In terms of EV user preferences, the required charging time is found to have the highest degree of importance, while V2G capability is the least important. The comparative analysis with state-of-the-art MCDM methods validates the proposed model results. Finally, sensitivity analysis verified the ranking order.
•A new methodology for selecting the best performing public charging station option.•Various EV user considerations at public charging stations are identified.•A flexible decision-making method with improved objective and rational reasoning.•An original aggregation mechanism for the fusion of rough RDB functions.•DCFC EVSE is found to be the best performing configuration.
To discover conceptual and behavioral barriers to electric vehicle (EV) charging, in-depth interviews were conducted in person with experienced and novice EV users. Mental models were found to affect ...vehicle charging strategies. Novice EV users drew from their existing mental models for petrol refueling and misapplied them to EV charging. Most experienced users had developed new mental models appropriate for the physical and temporal realities of EV charging—they are adapted to diverse rates of charge, EVs' longer energy filling duration, co-location of EV charging with certain user activities, and EVs drivers’ shorter equipment engagement time. Three predominant mental models for EV charging were found: 1. Monitor the fuel gauge, when low, seek a refill location (from liquid-fueling model), 2. Prior to a trip, plan where and when to charge, 3. Event-triggered charging (unique to the EV mental model). Misapplication of liquid fuel models to EVs has detrimental effects: more effort and more frequent anxiety regarding recharging, buyer choice of EV characteristics mismatched to need, manufacturer oversizing of batteries, policy overemphasis on fast public charging, and restricted opportunity to reduce load on the grid. Solutions are suggested to forestall or minimize these detrimental effects and facilitate EV adoption.
Three major mental models and associated refilling strategies were identified in this research: (A) Monitor gage, when low seek refill; this is the primary strategy for liquid fuel refilling. (B) The planning model, predominately used for EV long trips, occasionally used for petrol vehicle long trips. (C) The event-triggered model, exclusively used for EV recharging. Display omitted
•Qualitative interviews were conducted with novice and experienced EV users•Three mental models were discovered and found to guide EV charging behavior•EV charging behavior based on liquid fuel model leads to user problems and anxiety•Policy and private measures are suggested to improve EV user charging strategies
This study proposes a multi-objective optimization model to determine the optimal charging infrastructure for a transition to plug-in electric vehicles (PEVs) at workplaces. The developed model ...considers all cost aspects of a workplace charging station, i.e., daily levelized electric vehicle supply equipment (EVSE) infrastructure cost, PEV energy and demand charges. These single-objective functions are aggregated in a multi-objective optimization framework to find the Pareto optimal solutions. Smart charging strategies with interrupted and uninterrupted power profiles are proposed to maximize the use of EVSE units. The charging behavior model is developed based on collected workplace charging data. The model is tested with various scheduling policies to investigate their impact on the behaviors of EVSE types from different perspectives. Finally, a sensitivity analysis is performed to assess the impacts of battery sizes and onboard charger ratings on cost behavior. It is shown that the proposed model can achieve up to 7.8% and 14.6% cost savings as compared to single-objective optimal models and the current charging practice, respectively. The unit cost is found to be more sensitive to scheduling policies than the charging strategies. It is also found that the flexibility ratio policy gives the best PEV scheduling with the lowest unit cost and the most efficient use of the grid assets.
•A multi-objective optimization model for optimal workplace charging infrastructure.•The unit cost behavior of optimal EVSE configurations is investigated.•The impact of battery sizes and on-board charger levels on cost behavior is probed.•The impact of various scheduling policies is analyzed.•The performance of optimal EVSE configurations from various workplace perspectives.
The lack of public charging infrastructure is often referred to as an important barrier to the diffusion of electric vehicles. As the construction of charging stations is a costly endeavour, the ...question arises as to how maximum benefit for potential users can be achieved with limited resources. Therefore, our analysis deals with the factors that influence the attractiveness of public charging infrastructure from the perspective of potential users. Our analysis is based on the assessments of 1003 German car drivers on possible future charging infrastructure systems with different configurations regarding spatial coverage, charging duration and usage costs. We examined the preferences with regard to these features using a rating-based conjoint analysis. We also looked into the question of whether groups of car drivers can be identified that are characterised by specific preference constellations with regard to these features. Our key finding is that the majority of car drivers are unwilling to pay a basic fee for the possibility of using public charging infrastructure. Nevertheless, there are subgroups that value the public charging infrastructure more than other car drivers. In addition to implications for possible business models, this result indicates that public charging infrastructure could be important for attracting other target groups to electromobility besides classic early adopters of electric vehicles. Furthermore, our analysis shows that the charging duration at charging stations in cities and along the highway has a strong influence on the evaluation of the public charging infrastructure. The spatial coverage with charging stations in cities and along the highway, on the other hand, has a weaker influence. A central conclusion from this is that the existence of fast-charging stations should be prioritized over a close-meshed coverage with charging points when the charging infrastructure is expanded.
•Most car drivers are not willing to pay a basic fee for public charging.•However, there are target groups that value public charging significantly more.•Fast charging stations are more important than a dense network of charging points.
The utilization of electric vehicle (EV) charging equipment is a key driver of charging station economics, but current trends and factors related to the utilization of public charging infrastructure ...in the United States are not well understood. This study analyzes EV charging data from 3,705 nationwide public Level 2 (L2) and direct current fast charging (DCFC) stations over 2.5 years (2019-2022), observing utilization patterns over time. Regression analysis is used to assess the relationships between station utilization and several contextual and environmental factors. We conclude that local EV adoption is a strong indicator of utilization; L2 station utilization decreases with the size of the local charging network, while DCFC stations are less affected; and increased charging power has a greater effect on utilization for DCFC stations than L2. This study fills a critical research gap by reporting updated public charging station utilization statistics and analysis for the U.S. market.
With the rapid growth of electric vehicle (EV) ownership, attentions have been paid to the foundation of EVs, the electric vehicle supply equipment (EVSE). Different approaches of effort, among which ...battery swapping and fast charging are the two most well studied, have been made to solve the tradeoff problem between the battery charging speed and battery lifetime. There has been considerable debate over development strategy between charging and battery swapping. In passenger vehicles, the EV charging mode seems to dominate. But, does it mean that the battery swap mode is a dead-end? The answer should be "No". There are use cases showing that battery swap can have great potentials for some particular uses, such as taxis and buses. This paper uses Monte Carlo simulations of vehicle behaviors to compare the service capacities and earnings of EV charging and battery swapping for both taxi and bus fleets. Stochastic models of taxis, buses, charging stations (CSs) and battery swapping systems are set up. Subsequently, service capacities of the EVSE are compared. The impact of factors on the service capacity, such as the size of the vehicle's battery, vehicle's moving speed, the power of the CS, and the price of the swapping service is investigated. Finally, possible reasons of today's less prevalence of battery swapping stations are discussed. The results of the analysis, which can be helpful to policymakers and industry investors, show that with same service capacity, an EV battery swapping station could provide significantly more financial and social benefits for the vehicle operators and EVSE service providers than that of an EV CS.
This work highlights the significance of the exchange of digital data and signals between electric vehicles (EVs) and electric vehicle chargers in ensuring safe and reliable charging. Focus is placed ...on the globally adopted GB/T 27930-15 protocol for DC EV charging, with research efforts centered on developing firmware and hardware compliant with this protocol. Conformance testing of these modules is emphasized, alongside ongoing research aiming to optimize charging efficiency, enhance compatibility, and ensure interoperability across charging networks. Methodologies for lab-level pre-compliance testing are outlined, which involve utilizing test setups composed of digital controllers, hardware emulators, and specialized software.
This paper is an overview of fast charging for electrical vehicles. Specifically, it analyzes the impact of Ultra-Fast Charging Stations (UFCSs) on the distribution grid and their role in the smart ...grids. Moreover, the paper defines the framework of UFC, its diffusion and the associated new trends. The most frequently used converters in the conversion stages of DC charging stations with integrated generation are analyzed. To achieve this goal four active front end AC-DC converters (unidirectional and bidirectional), three isolated DC-DC converters as well as two control architectures are explored. In comparing the targeted configurations, the main target is set on categorizing them based on supply voltage level, type of smart grid, and power flow of the converters. Further, the paper outlines a broad overview of main standards for UFCSs and evaluation of the reliability, data collection, and operation of UFCSs. The paper aims to to link the needs of the designers of charging stations to preferences of the commercial market.
This paper provides an overview of the Standards applicable to electric vehicles at the vehicle and system level, including the EVSE, plugs and connectors, and battery pack. Several relevant standard ...documents are listed, as well as areas of emerging technology for each system. The standards development process is discussed briefly to provide insight into where stakeholders can get involved in the process. General certification requirements for each system are reviewed.
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