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  • 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.
41

Influential Factors in determining Electric Vehicle Charging Sales in kWh / Påverkansfaktorer av försäljningen av elektrisk fordonsladdning i kWh

Bergentoft, Isabelle, Friberg, Eloïse January 2023 (has links)
This study investigates the underlying factors driving OKQ8’s electric vehicle charging sales in kWh and aims to understand their customers better by identifying the factors that impact sales in the electric vehicle charging market. The study focuses on transactions from 17 OKQ8 stations in Sweden and Denmark, from July 1st, 2022, to February 28th, 2023, categorized into five distinct subgroups based on similar attributes. The report uses a multiple linear regression model in the programming language R and macroeconomic principles to identify the variables that lead to additional sales of electric vehicle charging.  The final regression model includes the variables Sales, Station, Month, Weekday, and Time, with an Adjusted R2 of over 68% for all five groups. The study reveals that price does not have a significant impact on the sales of charging. Moreover, the analysis highlights the significance of variables related to time, month, day of the week, and individual charging stations, which demonstrate varying impacts on charging sales across different groups.  The study provides valuable insights into the influence of price and consumer behavior on electric vehicle charging sales, emphasizing the importance of adopting strategic approaches to encourage a wider adoption of electric vehicles, enhance charging infrastructure, and consider government support such as subsidies or tax incentives. The study has some limitations, including a lack of data for March to May and only covering a single year, limiting the ability to identify recurring patterns. Nonetheless, the study’s findings provide insights into the factors affecting OKQ8’s sales of electrical vehicle charging and ongoing research is necessary to validate and expand upon these findings, considering the constantly evolving electric vehicle market. / Denna studie syftar till att undersöka de underliggande faktorer som påverkar försäljningen av laddning av elektriska fordon i kWh hos OKQ8 och strävar vidare efter att få en djupare förståelse för deras kundgrupp. Studien bygger på data som sträcker sig från den 1a juli 2022 till den 28e februari 2023 och är i form av transaktioner från 17 olika OKQ8-stationer i Sverige och Danmark. Dessa 17 stationer delas sedan sedan in i fem olika undergrupper där stationerna i varje undergrupp erhåller liknande egenskaper. Rapporten använder sig av en multipel linjär regressionsmodell i programmeringsspråket R, och makroekonomiska principer för att identifiera variabler som leder till ökad försäljning av laddning av elektriska fordon. Den slutliga regressionsmodellen inkluderar variablerna Försäljning, Station, Månad, Veckodag och Tid, där Adjusted R2 har ett värde över 68% för samtliga fem grupper. Studien avslöjar att priset inte har en signifikant inverkan på försäljningen av laddning och belyser vidare betydelsen av variabler relaterade till tid, månad, veckodag och individuella laddningsstationer, vilka visar en varierande signifikans på försäljningen av laddning inom de olika grupperna. Studien ger värdefulla insikter om konsumentbeteende kopplat till försäljning av laddning för elektriska fordon. Den betonar också vikten av att vidta strategiska åtgärder för att främja en mer omfattande spridning av elektriska fordon, förbättra laddningsinfrastrukturen och överväga regeringsstöd såsom subventioner eller skattelättnader. Studien har vissa begränsningar att ta hänsyn till, däribland avsaknad av data för perioden mars till maj och att den endast täcker ett år. Dessa begränsningar påverkar möjligheten att identifiera eventuella återkommande mönster. Trots detta bidrar studiens resultat med värdefulla insikter om de faktorer som påverkar försäljningen av laddning för elektriska fordon som OKQ8 kan dra nytta av i sin verksamhet. På grund av marknadens ständiga utveckling är det dock nödvändigt med fortsatt analys för att validera och vidareutveckla resultaten.
42

En elektrifiering av den interna busstrafiken på Stockholm Arlanda Airport

Zisimopoulos, Dimitrios January 2016 (has links)
Functional and cost effective systems for the full electrification of a bus network are areas of intense research and development. The electrification can be accomplished using different technological solutions, for example using opportunity charging or using an electric road system – ERS. Both opportunity charging and ERS have the potential to be integrated into already existing bus lines. With opportunity charging, the regular dwell time at the end stops is used for the bus to recharge its batteries and with an ERS the bus can charge dynamically along the road. The purpose of this report is to analyze how the existing Alfa- and Beta line at Stockholm Arlanda Airport, in a functional and cost effective way, can be electrified using either opportunity charging or an ERS. The tradeoff between required charging power, battery capacity and the necessity to change the existing running schedule is explained in detail. In addition, the impact on the electrical grid is analyzed based on different load profiles of different charging stations using different power levels. The analysis is based on real data from the Alfa – and Beta line with its existing buses, the electrical grid at Arlanda and data provided by both the leading (electrical) bus manufacturers and the leading charging infrastructure manufacturers.  The outcome of this report suggests that a full electrification of the existing Alfa- and Beta line has the potential to lower CO2-emissions and energy use at a functional and cost effective way.
43

Nätanslutning av en framtida elväg : En kartläggning av anslutningsmöjligheter för E4an mellan Gävle och Stockholm / Grid connection of a future electric road

Ekström, Amelie, Wänlund, Jessica January 2021 (has links)
The transport sector accounts for a third of Sweden’s total greenhouse gas emissions where cars and heavy trucks dominate the use of fossil fuels. The Swedish government is now intensifying the work for an electrified transport sector where electric roads could be an important part. Electric roads enable heavy vehicles to charge their batteries while driving, which is expected to contribute to environmentally friendly and time-efficient freight transports. To implement electric roads, availability of electric power along the electric roads will be required. This study presents a plan for connecting an electric road to the electricity grid in the electricity network area of Vattenfall Eldistribution. From the results, the idea was to present general conclusions from the experiences of the study, that could contribute in further implementation of electric roads.  The road that has been selected for the study was the E4 between Gävle and Stockholm. A model for calculating the power demand along the electric road has been modeled and connection possibilities to transformer stations has been investigated. The analysis was based on three scenarios where different degrees of strengthening of the existing electricity network were assumed. In addition, a forecast for 2030 and a cost estimation for each scenario has been carried out. The result of the study indicates that for road sections close to larger cities, there are a larger number of connection options in comparison to rural areas. Furthermore, the designed solution in the study required strengthening of the electricity grid and the investment cost was 362 million Swedish crowns.
44

Nätanslutning av en framtida elväg : En kartläggning av anslutningsmöjligheter för E4an mellan Gävle och Stockholm / Grid connection of a future electric road

Wänlund, Jessica, Ekström, Amelie January 2021 (has links)
The transport sector accounts for a third of Sweden’s total greenhouse gas emissions where cars and heavy trucks dominate the use of fossil fuels. The Swedish government is now intensifying the work for an electrified transport sector where electric roads could be an important part. Electric roads enable heavy vehicles to charge their batteries while driving, which is expected to contribute to environmentally friendly and time-efficient freight transports. To implement electric roads, availability of electric power along the electric roads will be required. This study presents a plan for connecting an electric road to the electricity grid in the electricity network area of Vattenfall Eldistribution. From the results, the idea was to present general conclusions from the experiences of the study, that could contribute in further implementation of electric roads. The road that has been selected for the study was the E4 between Gävle and Stockholm. A model for calculating the power demand along the electric road has been modeled and connection possibilities to transformer stations has been investigated. The analysis was based on three scenarios where different degrees of strengthening of the existing electricity network were assumed. In addition, a forecast for 2030 and a cost estimation for each scenario has been carried out. The result of the study indicates that for road sections close to larger cities, there are a larger number of connection options in comparison to rural areas. Furthermore, the designed solution in the study required strengthening of the electricity grid and the investment cost was 362 million Swedish crowns.
45

Smart charging of an electric bus fleet

Färm, Emil January 2021 (has links)
Controlling the balance of production and consumption of electricity will become increasingly challenging as the transport sector gradually converts to electric vehicles along with a growing share of wind power in the Swedish electric power system. This puts greater demand on resources that maintain the balance to ensure stable grid operation. The balancing act is called frequency regulation which historically has been performed almost entirely by hydropower. As the power production becomes more intermittent with renewable energy sources, frequency regulation will need to be performed in higher volumes on the demand side by having a more flexible consumption. In this report, the electrification of 17 buses Svealandstrafiken bus depot in Västerås has been studied. The aim has been to assess different charging strategies to efficiently utilize the available time and power but also to investigate if Svealandstrafiken can participate in frequency regulation. A smart charging model was created that demonstrated how smart charging can be implemented to optimize the charging in four different cases. The simulated cases were: charging with load balancing, reduced charging power, frequency regulation, and electrifying more buses. The results show that the power capacity limit will be exceeded if the buses are being charged directly as they arrive at the depot and without scheduling the charging session. By implementing smart charging, Svealandstrafiken can fully charge the 17 buses within the power capacity limit of the depot with 82 minutes to spare. By utilizing this 82-minute margin in the four different charging strategies, it was found that Svealandstrafiken can save 88 200SEK per year by load balancing, save 30 000 SEK per year by reducing the charging power by 10 %, earn 111 900 SEK per year by frequency regulation or electrify five more buses. Reducing the charging power may also increase the lifetime of the batteries but quantifying this needs further studies. Conclusively, there is economic potential for Svealandstrafiken for implementing smart charging.
46

DC-DC Converter for Fast Charging with Mobile BESS in a Weak Grid : Enabling remote charging and increased efficiency with less resource intensity / DC-DC-omvandlare för snabbladdning med mobilt batterienergilagringssystem i svaga elnät : Möjliggör laddning och ökad effektivitet med mindre resursintensitet på avlägsna platser

Medén, Alexander January 2023 (has links)
With the increase of electric vehicles (EVs) on the roads the availability of charging infrastructure becomes more important. Today it is relatively straightforward to install fast chargers in areas with strong power grid connections, such as in urban areas. However, in areas with less available electrical power, the grid is considered to be a weak grid, typically in remote areas, which limits charging speeds. Local peak shaving can be implemented with battery energy storage systems (BESS) to support faster charging at these locations by increasing available power when needed. As the majority of the power is supplied by the BESS there are noticeable conversion losses when converting from the BESS DC voltage to AC in the grid and then back to DC through the fast charger. This thesis investigates DC/DC converters to charge EVs directly from a BESS DC bus by regulating the voltage to the level of the EV, while also supporting safe simultaneous charging capability. It was done through understanding relevant standards’ requirements, converter review, as well as design and simulation of the interesting topologies. The converters selected to simulate were the Buck-Boost and the Dual-Active Bridge (DAB). After analysing the efficiency result in combination with industry requirements, it was concluded that one DAB per output is the preferred option in most use cases. This would potentially also reduce the material usage and carbon footprint of this type of infrastructure compared to the current solution. Furthermore, some suggestions were made for improving the design of DAB converter before making a prototype for real testing. / Denna avhandling har undersökt hur en snabbladdares effektelektronik för en mobil batterienergilagringssystem kan designas för att ladda två elbilar samtidigt. För att göra detta har systemkrav från relevanta standarder sammanställts och olika snabbladdares kapacitet undersökts. Därefter har olika DC/DC-omvandlare identifierats i ändamål att välja ut de mest lämpade för att uppfylla funktionen. De utvalda omvandlarna designades iterativt och simulerades med i verktyget PLECS för att kunna jämföra hur vardera omvandlare presterade under olika scenarior och med olika transistorer. Resultat och slutsatser från detta arbete är att galvanisk isolering krävs mellan de två elbilarna samt att två Dual-Active Bridge (DAB) omvandlare är den mest lämpade utifrån effektivitet, kapacitet och materialanvänding. Det finns även flera områden att fortsätta arbetet på för att förbättra designen och testa med en prototyp.
47

Market analysis for electric vehicle supply equipment : The case of China / Analys av marknaden för laddningsutrustning för elbilar : Fallet Kina

BUSK, ANDREY, JOELSSON WARRENSTEIN, ARVID January 2014 (has links)
Personliga eldrivna fordon (EV) är ett nytt teknikområde som är på väg att uppnå stort momentum på flera av världens marknader. Eftersom branschen fortfarande ligger i sin linda finns det i nuläget inga tydliga strukturer, som gäller för alla marknader världen över, gällande relationerna mellan aktörer, vilket leder till osäkerheter när det kommer till att ta strategiska beslut. Uppdragsgivaren för denna studie är Hong Kong EV Power Ltd. (EV Power), en Hongkong-baserad leverantör av laddningsstationer för elbilar och relaterade tjänster, som har ambitionen att inträda marknaden på det kinesiska fastlandet inom den närmaste framtiden. Emellertid har EV Power ännu inte bestämt sig vilken stad de vill rikta in sig på i det första skedet. Denna avhandling ämnar formulera en modell som kan användas för att utvärdera och jämföra geografiska marknader med avseende på lämpligheten för ett marknadsinträde av en leverantör av laddningsstationer för elbilar. Dessutom kommer modellen testas på tre städer på kinas fastland (Peking, Shanghai och Shenzhen), med syfte att komma fram till vilken stad som är mest attraktiv för EV Power, samt att utvärdera modellens funktionsduglighet. Sist kommer resultaten från utvärderingen av de tre städerna att tjäna som utgångspunkten för en analys som ämnar ta fram framgångsfaktorer för ett marknadsinträde på kinas fastland. För att uppnå detta har fyra olika datainsamlingsmetoder använts: Först studerades teori, med syfte att få bakgrundskunskap likväl som att få förståelse för specifika faktorer som påverkar ett marknadsinträde som detta. För det andra observerades EV Powers nuvarande verksamhet i Hong Kong, i avsikt att förstå vad som har lett till den framgång som företaget upplevt på sin hemmamarknad. För det tredje intervjuades branschexperter för att få ett perspektiv på branschen som helhet. Sist samlades sekundär data kring de tre städerna in, för att kunna utvärdera de olika faktorerna som ingår i den framtagna modellen. Den slutgiltiga modellen består av fem faktorer som påverkar en stads attraktivitet för ett marknadsinträde av en leverantör av laddningsstationer för elbilar. De identifierade faktorerna är: ’Marknadens tillgänglighet’, ’Kortsiktig efterfrågan’, ’Förväntad marknadsandel’, ’Vinstmarginal’ och ’Långsiktig produktpotential’. Dessa faktorer är i sin tur indelade i subfaktorer som har sina egna uppsättningar av drivare. Efter att ha använt modellen för att utvärdera de tre städerna konstaterades det att Shanghai är den lämpligaste staden för ett marknadsinträde av EV Power, främst på grund av stadens dominans på marknaden för privatanvända elbilar och ett gynnsamt regelverk. Slutligen hittades tre framgångsfaktorer för ett sådant inträde: ’Fokusera på tjänster’, ’Bibehåll partner-relationer’ och ’Inträd tidigt’. / Personal electric vehicles (EV) is an emerging technology that has gained much momentum in several markets during the past decade, and China is currently one of the markets where the growth in EV sales is the highest. Since the industry is still in its infancy, there are currently no clear structures regarding the relationships between different actors that apply to all markets globally, leading to great uncertainty in strategic decisions. The commissioner of this study is Hong Kong EV Power Ltd. (EV Power), a producer of EV supply equipment (EVSE) and related services in Hong Kong, which aspires to enter the Chinese mainland in the near future. However, EV Power has yet to decide which city they want to target first. This thesis aims to formulate a model that can be used to evaluate and compare geographic markets for a market entry by an EVSE company. Furthermore, the model is tested on three cities in Mainland China (Beijing, Shanghai and Shenzhen), in order to derive the most attractive city for EV Power and to evaluate the adequacy of the model. Lastly, with the results from the city evaluation, as a point of departure, success factors for an entry into Mainland China by the commissioning company will be summarized. In order to achieve this objective, four distinct data collection methods have been used: First, theory was studied, in order to gain background knowledge as well as to understand specific factors that impact a market entry decision such as this. Second, EV Power’s current business in Hong Kong was observed, with a view to achieve an understanding of what has led the company to experience success in its home market. Third, Interviews with industry experts were conducted, so as to get a perspective on the industry as a whole. Fourth and last, secondary data for the different cities was collected, for the sake of evaluating them according to the developed model. The final model consists of five main factors that encompass the elements that influence a cities level of attractiveness for entry by an EV charging station supplier. The identified factors are: ‘Market accessibility’, ‘Short-term demand’, ‘Expected market share’, ‘Profit margin’, and ‘Long-term product potential’. These factors are in turn divided into sub factors that have their own set of drivers. Using the model to evaluate the cities, it was found that Shanghai is the most suitable city for a market entry by EV Power, mainly due to its dominance in the market for private EVs and a favourable regulatory environment. Finally, three main success factors, for such a market entry, were found: ‘Focus on services’, ‘Maintain partner relationships’, and ‘Enter early’.
48

Thermal energy management and chemical reaction investigation of micro-proton exchange membrane fuel cell and fuel cell system using finite element modelling

McGee, Seán January 2015 (has links)
Fuel cell systems are becoming more commonplace as a power generation method and are being researched, developed, and explored for commercial use, including portable fuel cells that appear in laptops, phones, and of course, chargers. This thesis examines a model constructed on inspiration from the myFC PowerTrekk, a portable fuel cell charger, using COMSOL Multiphysics, a finite element analysis software. As an educational tool and in the form of zero-dimensional, two-dimensional, and three-dimensional models, an investigation was completed into the geometric construction, air conditions and compositions, and product materials with a best case scenario completed that summarizes the results identified. On the basis of the results of this research, it can be concluded that polyoximetylen and high-density polyethylene were considered as possible materials for the majority of the product, though a more thorough investigation is needed. Air flow of above 10 m/s, air water vapour mass fraction below 50% and initial temperature between 308K and 298K was considered in this best scenario. Suggestions on future expansions to this project are also given in the conclusion.

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