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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.
1

Proposal of wireless charging method and architecture to increase range in electric vehicles

Omar Nabeel Nezamuddin (10292552) 06 April 2021 (has links)
<div>Electric vehicles (EVs) face a major issue before becoming the norm of society, that is, their lack of range when it comes to long trips. Fast charging stations are a good step forward to help make it simpler for EVs, but it is still not as convenient when compared to vehicles with an internal combustion engine (ICE). Plenty of infrastructure changes have been proposed in the literature attempting to tackle this issue, but they typically tend to be either an expensive solution or a difficult practical implementation.</div><div> </div><div> This dissertation presents two solutions to help increase the range of EVs: a novel wireless charging method and a multi-motor architecture for EVs. The first proposed solution involves the ability for EVs to charge while en route from another vehicle, which will be referred to from here on as vehicle-to-vehicle recharging (VVR). The aim of this system is to bring an innovative way for EVs to charge their battery without getting off route on a highway. The electric vehicle can request such a service from a designated charger vehicle on demand and receive electric power wirelessly while en route. The vehicles that provide energy (charger vehicles) through wireless power transfer (WPT) only need to be semi-autonomous in order to ``engage'' or ``disengage'' during a trip. Also, a novel method for wireless power transfer will be presented, where the emitter (TX) or receiver (RX) pads can change angles to improve the efficiency of power transmission. This type of WPT system would be suitable for the VVR system presented in this dissertation, along with other applications.</div><div> </div><div> The second solution presented here will be an architecture for EVs with three or more different electric motors to help prolong the state of charge (SOC) of the battery. The key here is to use motors with different high efficiency regions. The proposed control algorithm optimizes the use of the motors on-board to keep them running in their most efficient regions. With this architecture, the powertrain would see a combined efficiency map that incorporates the best operating points of the motors. Therefore, the proposed architecture will allow the EV to operate with a higher range for a given battery capacity.</div><div> </div><div> The state-of-the-art is divided into four subsections relevant to the proposed solutions and where most of the innovations to reduce the burden of charging EVs can be found: (1) infrastructure changes, (2) device level innovations, (3) autonomous vehicles, and (4) electric vehicle architectures. The infrastructure changes highlight some of the proposed systems that aim to help EVs become a convenient solution to the public. Device level innovations covers some of the literature on technology that addresses EVs in terms of WPT. The autonomous vehicle subsection covers the importance of such technology in terms of safety and reliability, that could be implemented on the VVR system. Finally, the EV architectures covers the current typologies used in EVs. Furthermore, modeling, analysis, and simulation is presented to validate the feasibility of the proposed VVR system, the WPT system, and the multi-motor architecture for EVs.</div>
2

Evaluating Inductive Electric Road Systems Implementation : A multiple case study in Sweden

Nagarasan, Yuvanesh, Francis Xavier, Kevin Raja January 2020 (has links)
Sustainable transportation solutions are the goal for the future. With the technological shit happening in the transportation market towards electric vehicles, the electric road system (ERS) is a necessary technology required to reach the sustainability goals for the future. While many studies show the role of innovation in a socio-technical landscape, many neglect the diffusion process of the innovation which occurs to create a socio-technical change. The nature of this thesis is an exploratory case study with a qualitative approach. To address the study, a literature review for the diffusion of innovation, its characteristics, multi-level perspective, and technology readiness level (TRL) was presented in order to provide a better understanding and build a foundation for the research. A review of scientific articles regarding the electric road system was performed to provide insights and obtain information on the technology. The data from scientific articles were complemented by interviews from experts regarding electric road systems to obtain an understanding of technology if it was to be implemented in the future in Sweden. The empirics collected were analyzed using the literature framework and conclusions were drawn. Analyzing the data was required to find the factors hindering the technology and if there is a window of opportunity for the technology to exist in the Swedish market. Environmental sustainability has been the driving factor, but the rate of diffusion for the technology will depend on the complexity and the maturity of the technology to function as a whole working system. The study contributes to evaluating the implementation of an inductive electric road system in the Swedish context and if it could be a viable solution in the transportation market. The perspectives of the technology in the Swedish market and the motivation for the solution are discussed. An analytical contribution by evaluating if the technology could exist in the future and insights on the diffusion of the technology into the existing landscape.
3

Impact of smart EV charging on grid network with PV and BESS : Case study for Hammarby Sjöstad

Khalid, Mutayab January 2021 (has links)
The transition in the transport sector by the integration of battery electric vehicles (BEVs) brings a new challenge for the system operators to ensure the balance between supply and demand. The installation of new EV charges poses a surge in electricity demand in the coming years which jeopardizes the grid reliability and stability. With the new EV policies in place, Sweden will have a huge growth of BEVs and the associated charging infrastructures. The challenges faced by the electricity transmission and distribution will depend on the type and smart capability of the infrastructure. Therefore, research is conducted to analyze the impacts of the mix of public and private residential EV charging and how smart charging can help in mitigating the impacts. This thesis studies the impact of the mix of private residential and public EV chargers on the power network of Hammarby Sjöstad, a neighborhood of Stockholm. Four substations out of 20 corresponding to the areas with the highest proportion in the residential and commercial sectors in the network were chosen for the study and power flow analysis was carried out to analyze the impacts in the year 2025. EV chargers were categorized into public and private residential chargers. The public chargers had rated power of 22 kW each while residential chargers were rated at 3.68 kW each. EVs can behave as energy vectors, and it is possible to optimize their charging as a part of demand-side management which includes peak shaving or shifting. Optimizing EV charging was treated as a mixed integer linear programming (MILP) problem to schedule EV charging for both reducing losses and the cost of electricity import from the grid. Two optimization strategies were investigated to analyze their potential to reduce the peaks due to uncontrolled charging. Renewable energy generation from solar PVs integrated with EV chargers reduces the import of electricity from the grid during the day which not only reduced the losses but also the cost of importing electricity from the grid. The effect of intermittency of solar PV generation was reduced by implementing BESS. At low price periods, the BESS was charged using the excess PV power and at higher price periods, the BESS was discharged. Three scenarios were developed, where the Reference scenario refers to the base case without PV and BESS, With PV scenario considered only PV generation while With PVBESS scenario considered the implementation of BESS with PV. Three test cases were simulated for each of the scenarios, and it was found that by the implementation of smart charging, the losses in the network reduce by 35.5% and it also significantly reduced the losses in all the other scenarios. Implementation of smart charging reduced the cost of electricity import from the grid by 4.3%. The integration of PV generation led to a 7% further reduction in the losses and cost of electricity import as compared to the Reference scenario. The integration of BESS increased the losses in the network, but it also enhanced the self-consumption of PV power. The implementation of smart charging not only reduces the losses and costs of import but will lead to savings in grid reinforcement costs. / Övergången inom transportsektorn genom integrering av batteri -elektriska fordon (BEV) medför en ny utmaning för systemoperatörerna att säkerställa balansen mellan utbud och efterfrågan. Installationen av nya elavgifter innebär en kraftig ökning av elbehovet under de kommande åren, vilket äventyrar nätets tillförlitlighet och stabilitet. Med den nya EV -politiken på plats kommer Sverige att ha en enorm tillväxt av BEV och tillhörande ladd infrastrukturer. Utmaningarna för elöverföring och distribution beror på infrastrukturens typ och smarta kapacitet. Därför forskas för att analysera effekterna av blandningen av offentliga och privata EV -laddningar för bostäder och hur smart laddning kan hjälpa till att mildra effekterna. Denna avhandling studerar effekten av blandningen av privata bostäder och offentliga EV -laddare på kraftnätet i Hammarby Sjöstad, en stadsdel i Stockholm. Fyra transformatorstationer av 20 motsvarande de områden med den högsta andelen inom bostads- och kommersiella sektorer i nätet valdes ut för undersökningen och effektflödesanalys utfördes för att analysera effekterna år 2025. EV -laddare kategoriserades offentligt och privata bostadsladdare. De offentliga laddarna hade en nominell effekt på 22 kW vardera medan bostadsladdare var 3,68 kW vardera. Elbilar kan bete sig som energivektorer, och det är möjligt att optimera laddningen som en del av hanteringen på efterfrågesidan som inkluderar topprakning eller växling. Optimering av EV -laddning behandlades som ett blandat heltal linjärt programmeringsproblem (MILP) för att schemalägga EV -laddning för både minskning av förluster och kostnader för elimport från nätet. Två optimeringsstrategier undersöktes för att analysera deras potential att minska topparna på grund av okontrollerad laddning. Förnybar energiproduktion från solcellsanläggningar integrerade med EV -laddare minskar importen av el från nätet under dagen vilket inte bara minskade förlusterna utan också kostnaderna för att importera el från nätet. Effekten av intermittency av solcellsgenerering genererades genom att implementera BESS. Vid lågprisperioder debiterades BESS med överskott av PV -effekt och vid högre prisperioder laddades BESS ur. Tre scenarier utvecklades, där referensscenariot hänvisar till basfallet utan PV och BESS, med PV -scenario endast betraktat PV -generering medan With PVBESS -scenario övervägde implementeringen av BESS med PV. Tre testfall simulerades för vart och ett av scenarierna, och det visade sig att genom implementering av smart laddning minskar förlusterna i nätverket med 35,5% och det minskade också avsevärt i alla andra scenarier. Genomförandet av smart laddning minskade kostnaden för elimport från nätet med 4,3%. Integrationen av PV -produktion ledde till en ytterligare minskning av förlusterna och kostnaderna för elimport med 7% jämfört med referensscenariot. Integrationen av BESS ökade förlusterna i nätet, men det förbättrade också självförbrukningen av PV-kraft. Genomförandet av smart laddning minskar inte bara förluster och kostnader vid import utan leder till besparingar i nätförstärkningskostnader.

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