Wireless charging of the EVs offers a convenient, reliable, and automatic charging of the autonomous vehicles without user interference. The focus of this thesis is the design and optimization of new structures for stationary EV wireless charging applications. The fundamentals of the Wireless Power Transfer (WPT) system and its main components including the magnetic couplers, transmitter and receiver power converters, and control methods are studied in depth. The requirements of the EV wireless charging application and design criteria are discussed in detail. The advantages and disadvantages of each topology are highlighted, and possible candidates for EV wireless charging applications are selected. Optimization of the resonant networks in terms of maximum efficiency and misalignment tolerance is studied. Different resonant topologies are studied in detail and their sensitivity functions are extracted. For each topology, an efficiency model is presented that includes the inverter, resonant capacitors, resonant inductor, diode-bridge, and core and conduction losses. Each topology is optimized with two different objective functions and the results are compared through the simulation and experiments. According to the optimization results, suitable topologies for the EV wireless charging application are selected. In order to increase the power density of the wireless charging system, and save ferrite material, integrated inductors into the magnetic couplers are proposed. In this structure, the DC-DC inductor is integrated into the receiver main coil and the resonant inductor is integrated into the transmitter coil. This integration introduces new challenges to the design of the resonant network and magnetic coupler due to the unwanted cross-coupling effect. To address this issue, the fully integrated magnetic structure is optimally designed to have minimum cross-coupling. Moreover, the resonant network is designed based on an optimization problem that includes the cross-coupling into the system equations to ensure maximum efficiency. The proposed fully-integrated magnetic structure is built and experimental tests are presented to validate the performance of the proposed magnetic structure and its optimization method. To reduce the implementation cost, size and weight a PCB-based magnetic coupler is proposed to replace the Litz wire in the magnetic coupler of the WPT system. Moreover, the proposed PCB-magnetic coupler increases the repeatability of the design and reduces manufacturing errors. The PCB-based magnetic coupler is studied through Finite Element Analysis (FEA) to minimize the AC resistance of the coil. Different parameters such including the number of the PCB layers, copper cross-section, and layer thickness are studied in detail to evaluate their effect on the coil resistance. Thermal analysis is performed to ensure the feasibility of the design under different loading conditions. A 3.3 kW/85 kHz wireless charging system is built and experimental tests are presented. A novel modular resonant topology for fast wireless charging is proposed. A modular structure offers reliability, scalability, and better thermal management. The proposed topology is made by multi-parallel inverter legs connected to an LCC resonant network. The outputs of the resonant networks are connected in parallel to feed the transmitter coil with a high excitation current. The proposed modular system is compared with a conventional system and it showed superior performance in different aspects. / Thesis / Doctor of Philosophy (PhD)

This thesis presents changes to the design of the Prototype Vehicles Laboratory (PROVE Lab) Endurance Car, an electric car intended to break the Guinness World Record for the single-charge range of an electric vehicle. The design range is 1609.34 km, however at the design velocity of 104.6 kph, the drag is 196 N; which requires more battery capacity than the 100 kWh maximum of the baseline model. With a fixed frontal area, drag reduction can come from lowered velocity or reduced CD. CD reduction is attempted in four ways: side skirts between the fenders, a raised ride height, an elongated diffuser, and a widened rear. Side skirts were added to move pressure recovery from the front ducts to the diffuser by lowering the pressure between the side skirts; this had the intended effect but increased the tendency of the flow to separation in the already-separated areas. There was no significant change in pressure drag, but the shear drag and downforce increased. The ride height was increased to reduce drag and downforce; this change did not have a significant effect on the resultant forces and the separation on the underbody was largely unchanged. The diffuser was extended by 12.7 cm without modifying the aspect ratio, to lower the divergence angle. The pressure and shear drag reduced by 8 N and 1.1 N, respectively, and downforce decreased by 80 N, but separation in the diffuser was not eliminated. Finally, the fourth strategy reduced the divergence angle to approximately zero degrees by widening the center of the vehicle. This decreased pressure drag by 13 N and downforce by 188 N. Additionally, this strategy allows a larger 180 kWh battery, which permits 1609.34 km of range at 104.6 kph.

Bakgrund: De senaste åren har svenska privatpersoner aktiehandel ökat markant. Det låga ränteläget tillsammans med lägre entrébarriärer har resulterat i att ett stadigt inflöde av nya användare har tillkommit till plattformar för aktiehandel. Det är dock ingen lätt uppgift att skapa överavkastning. Föreliggande studie ämnar undersöka om det med hjälp av relativvärdering kan skapas en strategi som konsekvent kan skapa en riskjusterad överavkastning. Studien har valt att fokusera på den nordiska verkstadsindustrin, som historiskt har gett en stabil avkastning och innehåller flera väletablerade företag. Syfte: Studiens syfte är att analysera om man med hjälp av nyckeltalen P/E, EV/EBITDA, P/B, EV/S och förändring av Cash Conversion Cycle kan skapa riskjusterad avkastning på nordiska verkstadsföretag som är högre än jämförelseindex under perioden 2012–2022. Metod: För att uppfylla studiens syfte har en kvantitativ studie med en deduktiv ansats använts. Ett urval ur Nasdaqs listade industriaktier med rensade från producerande och finansiella företag har använts för att skapa portföljer baserade på P/E, P/B, EV/S, EV/EBITDA och ΔCCC. Totalt 10 portföljer skapades, 5 baserade låga respektive 5 på höga nyckeltal. Portföljerna har sedan ombalanserats årligen, den observerade avkastningen har sedan riskjusterats och satts emot ett jämförelseindex. Resultat: Höga EV/EBITDA-, höga EV/S-, låga EV/EBITDA-, låga EV/EBITDA- och störst negativ ΔCCC-portföljerna presterade överavkastning under den aktuella perioden mellan 2012–2022 för verkstadsföretag i Norden. Portföljen som bestod av höga EV/EBITDA-aktier skapade högst riskjusterad avkastning. Totalt presterade 50% av portföljerna högre riskjusterad avkastning än jämförelseindex. Ingen av de överpresterande portföljerna visade sig vara signifikanta. / Background: In recent years, Swedish private equity trading has increased markedly. The low interest rate in addition to fewer entry barriers have resulted in a steady influx of new users of stock trading platforms. However, creating excess returns is no easy task. This study intends to investigate whether, with the help of relative valuation, a strategy can be created that can consistently create a risk-adjusted excess return. The study has chosen to focus on the Nordic manufacturing companies, which has historically provided a stable return and includes several well-established companies. Purpose: The purpose of the study is to analyze whether the key figures P/E, EV/EBITDA, P/B, EV/S and Changes in Cash Conversion Cycle can create a risk adjusted return on Nordic manufacturing companies that is higher than the comparable stock index during the period 2012–2022. Method: To fulfill the purpose of the study, a quantitative study with a deductive approach has been used. A sample of Nasdaq listed industrial shares cleared of non-producing and financial companies has been used to create portfolios based on P/E, P/B, EV/S, EV/EBITDA and ΔCCC. A total of 10 portfolios were created, 5 based on low and 5 on high key figures. The portfolios have since been rebalanced annually, the observed return has since been risk adjusted and compared against a comparable index. Result: High EV/EBITDA-, high EV/S-, low EV/EBITDA-, low EV/EBITDA- and the largest negative ΔCCC portfolios achieved excess returns during the period between 2012–2022 for manufacturing companies in the Nordic countries. The portfolio consisting of high EV/EBITDA stocks created the highest risk-adjusted return. In total, 50% of the portfolios performed higher risk adjusted return than the benchmark index. None of the overperforming portfolios proved to be significant.

No description available.

No description available.

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.

Background: In recent years, the interest in investing has increased, and a growing number of people want to put their money into assets that are expected to increase in value. This is usually easier said than done, and it requires the investor to use a solid strategy. Because there are many methods of making an investment decision, this process can appear to be complicated. Multiple strategy is a well-known type of strategy that aims to build a portfolio based on different multiples. As a result, it is interesting to analyze what types of multiples perform best and worst when using a multiple strategy.  Purpose: The purpose of the study is to analyze the multiples EV/S, EV/EBITDA and P/E as a basis for a multiple strategy for companies found in the index S&P 500 to see if these can generate excess returns.  Methodology: A quantitative method with a deductive approach was best suited to fulfill the purpose of the study. Based on a selection of 411 companies through the period 2003 – 2021 twelve portfolios have been created with the 20 highest and lowest EV/S, EV/EBITDA or P/E multiples, with holding periods of either three or twelve months before rebalancing.  Results: The study results show that all multiples managed to outperform the benchmark index over the study period. Six out of the twelve portfolios were also able to show a significant return. The portfolio with low EV/S multiples and 12-month holding period generated the highest risk-adjusted return. / Bakgrund: På senare år har investerarintresset ökat och allt fler vill in och placera sitt kapital i tillgångar som förväntas öka i värde. Detta är något som oftast är lättare sagt än gjort och det krävs att investeraren använder sig av en tydlig strategi. Att det finns många olika sätt att komma fram till ett investeringsbeslut gör att denna process kan uppfattas som mycket komplicerad. En känd typ av strategi är multipelstrategi, som ämnar att bygga portföljen utifrån bolagens olika multiplar. Vilket gör det intressant att analysera vilka typer av multiplar som fungerar bättre respektive sämre vid användning av en multipelstrategi. Syfte: Studiens syfte är att analysera multiplarna EV/S, EV/EBITDA och P/E som grund till en multipelstrategi för bolag som återfinns i indexet S&P 500 för att se om dessa kan generera överavkastning. Metod: En kvantitativ metod med en deduktiv ansats var bäst lämpad för att uppnå studiens syfte. Utifrån ett urval av 411 bolag under perioden 2003 – 2021 har 12 portföljer skapats med de 20 högsta respektive lägsta EV/S-, EV/EBITDA- och P/E-multiplarna med innehavsperioder på antingen 3 eller 12 månader innan rebalansering. Resultat: Studiens resultat visar på att samtliga multiplar lyckades överavkasta jämförelseindexet över studiens period. 6 av 12 portföljer visade på en statistiskt signifikant avkastning. Portföljen med låga EV/S-multiplar och 12 månaders innehavsperiod genererade högst riskjusterad avkastning.

For the purpose of this study, data for low voltage distribution transformer loading in small communities in Maryland was collected from a local electric utility company. Specifically, analysis was done on three distribution transformers on their system. Each of these transformers serves at least one electric vehicle (EV) owner. Of the three transformers analyzed, Transformer 2 serves eight residential homes and has the highest risk of experiencing an overload if all customers purchase at least one EV. Transformer 2 has a nameplate rating of 25kVA (22.5kW assuming a 0.9 power factor). With one EV owner, Transformer 2 has a peak load of 46.82kW during the study period between August 4 and August 17, 2013. When seven additional EVs of different types were added in a simulated scenario, the peak load for Transformer 2 increased from 46.82kW to 89.76kW, which is outside the transformer thermal limit. With the implementation of TOU pricing, the peak load was reduced to 56.71kW from 89.76kW. By implementing a combination of TOU pricing and appliance cycling through demand side management (DSM), the peak load was further reduced to 52.27kW. / Master of Science

The adoption of Electric Vehicles (EVs) represents a transformative change in the automotive industry. As more households make the transition to EVs, the traditional dependence on fossil fuels for transportation is being replaced by electricity as the primary energy source. This transition has the potential to increase the electricity consumption within households as well as the demand on the power grids. To maximize the environmental and economic benefits of EV adoption, strategies regarding efficient energy management, integration of renewable energy source, and grid capacity are becoming essential considerations. The current dissertation research is motivated toward evaluating the adoption of EV and its impact on the US household’s energy demand. In pursuit of these goals, this research has made several contributions. First, we proposed an econometric framework to estimate the factors influencing customers’ vehicle purchase decisions. Second, a comparative analysis is conducted between two econometric frameworks –panel mixed random utility maximization MNL model and panel mixed random regret minimization MNL model to estimate the evolving landscape of EV adoption over time. Third, we employed an advanced econometric framework- Multiple Discrete Continuous Extreme Value (MDCEV) model– to evaluate the factors that influence the energy consumption profile of various household end-uses along with their alternating trends over time. Fourth, we employed a novel fusion approach to the MDCEV model to assess the impact of travel behavior along with several household socioeconomic characteristics on various energy end-uses. Finally, by predicting household EV ownership, projections of total household energy demand for the city of Atlanta for the years 2030, 2040 and 2050 are performed. A set of independent variables including vehicle attributes, socio-economic attributes, travel behavior-related attributes, dwelling attributes, appliance-use related attributes, and climate-related attributes from various data sources are employed in this study. The research concludes with an analysis of different policy implications.

Bakgrund: Målet med de flesta investeringar är att nå en hög avkastning till låg risk. Tidigare forskning har identifierat möjligheter till att överträffa marknaden vilket motsäger hypotesen om den effektiva marknaden. Investeringar i småbolag har blivit alltmer attraktivt de senaste åren vilket lyfter frågan angående hur en investering i dessa aktier kan genomföras på ett framgångsrikt sätt. Småbolagsaktier, och framförallt de allra minsta aktierna sett till marknadsvärde, förknippas ofta med högre risk. Detta medför att det är av relevans att undersöka huruvida en riskjusterad överavkastning är möjlig vid en applicering av dessa med befintliga investeringsstrategier. Syfte: Syftet med denna uppsats är att analysera huruvida det existerar en småbolagseffekt på den svenska aktiemarknaden mellan 2007-2019. Studien syftar även till att undersöka om det går att generera riskjusterad överavkastning vid investeringar i småbolagsaktier genom att kombinera dessa med alternativa investeringsstrategier som momentumeffekten samt relativvärdering i form av bolag med låga EV/EBITDA- multiplar. Metod: Studien har genomförts med en kvantitativ metod och en deduktiv ansats. Nio portföljer har konstruerats utefter olika bolagsstorlekar samt olika investeringsstrategier under tidsperioden 2007-2019 på den svenska aktiemarknaden. Dessa portföljer har sedan utvärderats sett till både avkastning samt riskjusterad avkastning för att slutligen testas statistiskt genom parata t-test. Slutsats: En småbolagseffekt kunde inte observeras på den svenska aktiemarknaden under den studerade tidsperioden. De portföljer som baserades på bolagen med lägst marknadsvärde presterade en signifikant lägre avkastning än jämförelseindexet. Vid en applicering av momentumeffekten samt låga EV/EBITDA- multiplar på småbolag kunde däremot fyra av fyra portföljer observeras generera en riskjusterad överavkastning relativt jämförelseindexet. Denna överavkastning kunde dock inte säkerställas statistiskt och skulle därmed kunna vara slumpmässig. / Background: The goal of most investments is to achieve a high return at a low risk. Previous research has identified opportunities to exceed the market, which contradicts the efficient-market hypothesis. Investments in small enterprises have become increasingly popular in recent years, which raises the question of how an investment on these markets can be done successfully. Small company shares, and especially the smallest shares in terms of market value, are often associated with higher risk. This means that a study that investigates whether a risk-adjusted excess return is possible with the application of existing investment strategies is of relevance. Purpose: The aim of this study is to analyze whether there exists a small firm effect on the Swedish stock market between the years 2007-2019. The study also aims to investigate whether it is possible to generate risk-adjusted excess returns when investing in small companies and combine these investments with alternative strategies such as the momentum effect and relative valuation in terms of companies with low EV / EBITDA multiples. Methodology: The study was conducted with a quantitative methodology and a deductive design. Nine portfolios were designed with different company sizes and based on different investment strategies during the period 2007-2019 on the Swedish stock market. These portfolios have then been evaluated in terms of both returns and risk-adjusted returns and the results were then finally statistically tested through the implement of parwise t-tests. Conclusion: A small firm effect could not be observed on the Swedish stock market during the examined time period. The portfolios based on the companies with the lowest market value generated a significantly lower return than the benchmark index. Meanwhile, when applying the momentum effect and the strategy of low EV/EBITDA multiples on small companies, four out of four portfolios were found to generate a risk-adjusted excess return relative to the benchmark index. However, this excess return could not be statistically proven and could thus be the result of randomness.