• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Method for Optimizing for Charging Cost in Electric Vehicle Routing

Lehrer, Matthew January 2023 (has links)
Adoption of electric vehicles has been restrained by the availability of charging stations and consumer fear of being stranded with a depleted battery, far from the nearest charger. In many areas of the world, charging stations are now widely available and the transition from vehicles with internal combustion engines is accelerating, though still in a fairly early stage. For electric vehicle drivers in those areas, anxiety that they will not be able to find a charger (“range anxiety”) is subsiding. However, differences in charging speed and pricing between stations and different outlets at the same station can be large. Total trip duration can vary significantly based on the charging outlet selected. Prior research has developed methods for helping all drivers find the fastest route and for electric vehicle drivers to ensure that they are able to complete their trip. Additional research has explored other complexities of route selection for electric vehicles such as how to select optimal stations for charging based on the total trip duration, including driving and charging time. Pricing for recharging electric vehicles at public chargers is more complex and diverse than for gas filling stations due to the differences in charging rates and the relatively low competition. This research investigates those differences. Using design science research methodology, a method is presented for determining which charging stops result in the lowest possible charging cost for a given route. The method is demonstrated through experiment with random routes within Sweden. The experimental results show that the average cost savings as compared to the duration-optimal route is 15% and 139 SEK per additional hour of trip time. One possible direction for future work is to improve the performance of the algorithm for use in real-time consumer route planning applications.
2

A Labeling Algorithm for the Resource Constrained Elementary Shortest Path Problem

Enerbäck, Jenny January 2024 (has links)
As the interest in electric heavy-duty vehicles has grown, so has the need for route planning tools to coordinate fleets of electric vehicles. This problem is called the Electric Vehicle Routing Problem (EVRP) and it can be solved using a Branch-Price-and-Cut method, where routes for individual vehicles are iteratively generated using information from the coordinated problem. These routes are computed in a pricing problem, which is a Resource Constrained Elementary Shortest Path Problem (RCESPP). Because of its iterative nature, the Branch-Price-and-Cut method is dependent on a fast solver for this RCSPP to get a good computational performance. In this thesis, we have implemented a labeling algorithm for the RCESSP for electric vehicles with state-of-the-art acceleration strategies. We further suggest a new bounding method that exploits the electric aspects of the problem. The algorithm's performance and the effect of the different acceleration strategies are evaluated on benchmark instances for the EVRP, and we report significantly improved computational times when using our bounding method for all types of instances. We find that route relaxation methods (ng-routes) were particularly advantageous in test instances with a combination of clustered and randomly distributed customers. Interestingly, for test instances with only randomly distributed customers, ng-relaxation required longer processing time to achieve elementary optimal routes and for these instances, the bounding methods gave better computational performance.
3

Electric Vehicle Routing Problems : models and solution approaches / Problèmes de tournées de véhicules électriques : modèles et méthodes de résolution

Montoya, Jose-Alejandro 09 December 2016 (has links)
Étant donné leur faible impact environnemental, l’utilisation des véhicules électriques dans les activités de service a beaucoup augmenté depuis quelques années. Cependant, leur déploiement est freiné par des contraintes techniques telles qu’une autonomie limitée et de longs temps de charge des batteries. La prise en compte de ces contraintes a mené à l’apparition de nouveaux problèmes de tournées de véhicules pour lesquels, en plus d’organiser les tournées,il faut décider où et de combien charger les batteries. Dans cette thèse nous nous intéressons à ces problèmes au travers de quatre études. La première concerne le développement d’une métaheuristique en deux phases simple mais performante pour résoudre un problème particulier appelé "Green VRP”. Dans la seconde, nous nous concentrons sur la modélisation d’un aspect essentiel dans ces problèmes : le processus de chargement des batteries. Nous étudions différentes stratégies pour modéliser ce processus et montrons l’importance de considérer la nature non linéaire des fonctions de chargement. Dans la troisième étude nous proposons une recherche locale itérative pour résoudre des problèmes avec des fonctions de chargement non linéaires. Nous introduisons un voisinage dédié aux décisions de chargement basé sur un nouveau problème de chargement sur une tournée fixée. Dans la dernière étude, nous traitons un problème réel de tournées de techniciens avec des véhicules classiques et électriques. Ce problème est résolu par une métaheuristique qui décompose le problème en plusieurs sous-problèmes plus simples résolus en parallèle, puis qui assemble des parties des solutions trouvées pour construire la solution finale. / Electric vehicles (evs) are one of the most promising technologies to reduce the greenhouse gas emissions. For this reason, the use of evs in service operations has dramatically increased in recent years. Despite their environmental benefits, evs still face technical constraints such as short autonomy and long charging times. Taking into account these constraints when planning ev operations leads to a new breed of vehicle routing problems (vrps), known as electricVrps (evrps). In addition, to the standard routing decisions, evrps are concerned with charging decisions: where and how much to charge. In this ph. D thesis, we address evrps through 4 different studies. In the first study, we tackle the green vehicle routing problem. To solve the problem, we propose a simple, yet effective, two-phase matheuristic. In the second study, we focus a key modelling aspects in evrps: the battery charging process. We study different strategies to model this process and show the importance of considering the nonlinear nature of the battery charging functions. InThe third study, we propose an iterated local search to tackle evrp with non-linear charging functions. We introduce a particular local search operator for the charging decisions based on a new fixedroute charging problem. The fourth and last study considers a real technician routing problem with conventional and electric vehicles (trp-cev). To tackle this problem, we propose a parallel matheuristic that decomposes the problem into a set of easier-to-solve subproblemsThat are solved in parallel processors. Then the approach uses parts of the solutions found to the subproblems to assemble final solution to the trp-cev.

Page generated in 0.0699 seconds