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Denna studie undersöker det tolkningsutrymme som kan komma att uppstå på grund av oklarheter i förfarandet vad gäller tillfälliga samarbetskonstellationer. Studien är en fallstudie av kvalitativ art och empirin har insamlats med hjälp av semistrukturerade intervjuer. Fallet består av en samarbetskonstellation och dess beslutsprocess inför en eventuell etablering av en dryport i kommunerna Bjuv och Åstorp. Studien påvisar att det finns oklarheter som har lett till ett tolkningsutrymme var i de olika aktörerna ges möjlighet till att behålla och utveckla sina egna tolkningar av det aktuella problemområdet. Detta har i sin tur lett till att aktörer som i konstellationens början kände sig tveksamma till projektet har ändrat uppfattning och fått en mer positiv syn på situationen. Studien visar vidare på att frivilligheten för deltagande kan ändras med tiden och att detta kan ske i det så kallade tolkningsutrymmet. Frivilligheten kan även påverkas av olika beroendeförhållanden i relation till samarbetskonstellationen. / This study investigates the margin for interpretation that can rise due to uncertainties in the procedure for temporary constellations for cooperation. The study is a case study of qualitative nature and the empiric part has been collected with semi–structured interviews. The case consists of a constellation for cooperation and its decision process for a potential establishment of a dryport in the municipalities of Bjuv and Åstorp. The study shows that there are unclear points that have led to a margin for interpretation where the different actors are given the possibility to keep and develop their own interpretation of the problem area. This has in turn led to that the actors, that at the start of the constellation were doubtful to the project, have changed their view into a more positive one. Furthermore, the study shows that the voluntary participation can change over time and that this can happen within the so called margin for interpretation. The voluntariness can also be affected by different interdependencies in relation to the constellation for cooperation.

The concept of circular economy has gained a lot of interest among both researchers and practitioners. Moving from the traditional linear “take, make, disposal” resource management approach towards circular economy principles that aim to keep resources in a loop of usage is considered to be a possible way for material-intensive industries to decouple economic growth from environmental constraints. This could enable increased value creation while maintaining a decreased environmental footprint. The transition towards circular economy has stimulated companies across industries to introduce varying types of circular business model innovations. By using the case of clothing resale in the fashion industry, this thesis aims to explore how companies innovate their business models in the context of circular economy. The study uses the Multi-Level Perspective framework to analyze the emerging business model innovations within the clothing resale markets, incumbent fashion retailers’ reactions towards them, and the role of innovating business models in possible future stages of the fashion industry’s transition towards circular economy. The findings show that the main types of business model innovations emerging in the highly growing clothing resale markets are born-circular fashion retailers, online resale platforms, B2B back-end services for clothing resale and clothing as a service. Most incumbent fashion retailers have been actively monitoring the development of the clothing resale market, but only a small part of them have introduced resale-related business models themselves. Some fashion retailers that have taken a more active approach towards clothing resale have followed a business model diversification strategy where the existing business model stays in place and a secondary resale business model is established parallel with the core business model. Although the clothing resale business model innovations can entail some short-term economic and brand benefits especially with specific product types and price segments, the largest benefits are likely to be related to preparing for future changes. Fashion retailers that are currently reacting early to the circular economy transition by diversifying their business model with novel resale business model innovations strengthen their future position if changes in regulatory frameworks, consumer mindsets and technologies further accelerate the importance of circular economy in the industry. / Begreppet cirkulär ekonomi har fått ett stort intresse bland både forskare och utövare. Genom att förflytta ifrån den traditionella linjära resurshanteringsstrategin: "ta, göra, bortskaffa", till principerna för cirkulär ekonomi. Principerna syftar till att istället hålla resurserna i en slinga av användning och anses vara ett möjligt sätt för materialintensiva industrier att koppla från den ekonomiska tillväxten från miljöbegränsningar, där en cirkulär ekonomi kan möjliggöra ökad värdeskapande samtidigt som ett minskat miljöavtryck bibehålls. Övergången till en cirkulär ekonomi har stimulerat företag över en mängd olika branscher att införa olika typer av cirkuläraffärsmodellsutveckling. Genom att studera det nya fenomenet av återförsäljning av kläder inom modebranschen, syftar examensarbetet att undersöka hur företag utvecklar sina affärsmodeller i samband med cirkulär ekonomi. Studien använder ett multi-perspektivramverk för att analysera de nya affärsmodellinnovationerna inom klädåterförsäljningsmarknaderna. Utöver det studeras även de nuvarande modeförsäljares reaktioner gentemot dessa samt rollen som innovativa affärsmodeller kan ha i framtida stadier av modebranschens övergång till cirkulär ekonomi. Resultaten visar att de viktigaste typerna av affärsmodellinnovationer på de signifikant växande marknaderna för återförsäljning av kläder är de `föddes-cirkulära´ modeförsäljarna, återförsäljningsplattformar på nätet, samt B2B-tjänster för återförsäljning av kläder och kläder som en tjänst. De flesta nuvarande modeförsäljare har aktivt övervakat utvecklingen av marknaden för klädåterförsäljning, men bara en liten del av dem har själva infört återförsäljningsrelaterade affärsmodeller. Vissa modeförsäljare som har tagit ett mer aktivt förhållningssätt till återförsäljning av kläder har följt en strategi för diversifiering av affärsmodeller där den befintliga affärsmodellen förblir på plats och en sekundär affärsmodell för återförsäljning upprättas parallellt med den huvudsakliga affärsmodellen. Trots att utveckling av affärsmodellens klädesåterförsäljning kan medföra ekonomiska fördelar och varumärken på kort sikt, särskilt med specifika produkttyper och prissegment. Förutses de största fördelarna troligen vara relaterat till förberedelser för framtida förändringar. Modeaktörer som reagerar tidigt på övergången till cirkulär ekonomi genom att diversifiera den befintliga affärsmodellen med nya innovationer eller kompletterar med en ny affärsmodell, stärker sin framtida position om förändringar i regelverk, konsumentens tankesätt och teknik ytterligare påskyndar vikten av cirkulär ekonomi i branschen.

The electric power system is undergoing a paradigm change on how electric energy is generated, transmitted, and delivered. Power electronics systems which can provide medium-voltage (MV) to high-voltage (HV) output (>13.8 kV ac, > 20 kV dc) with much faster dynamic response (> 10 kHz bandwidth) or high switching-frequency will enable new electronic energy network architectures, like MVDC power delivery, underground solid-state power substation (SSPS), and high-density power electronics building block (PEBB); help drive the levelized cost of electricity (LCOE) of renewable energy on par with conventional power generation; deliver precise and clean power to loads like high-speed electric motors; push the future power system toward 100% renewable energy and energy storage supplied. In the MV to HV area, the power conversion solution is dominated by silicon devices, like SCR, IGCT, and IGBT, which are slow in nature, posing significant switching losses and bulky auxiliary components like turn-on snubbers. Devices in series are required to reach higher voltage. High-frequency HV converter in two-level or three-level bridges running 20 kHz or higher in many emerging applications, like MVDC networks with high-frequency transformers and energy storage integration is hard to be built by silicon solutions. The emerging HV wide-bandgap (WBG) power semiconductors, e.g., 10 kV SiC MOSFETs offer higher blocking capability, faster and more efficient switching performances. This makes the high-frequency power conversion technology feasible for the MV area. To build a MV high-frequency power converter with high-power density, 10 kV SiC MOSFETs in series are required to reach >10 kV operation dc voltage as the single device rating is still limited by the semiconductor process and packaging capability. However, the knowledge of dynamic voltage sharing of high-speed HV SiC devices under high dv/dt rate and effective balancing methods are not fully explored. Both the voltage imbalance and the robust device voltage balancing control are not studied clearly in the existing literature. This dissertation evaluates the voltage imbalance of series-connected 10 kV SiC MOSFETs thoroughly. The parasitic capacitors connected with device terminals are found to be a unique factor for the voltage imbalance of series-connected SiC MOSFETs, which have a significant impact on the dv/dt of different devices based on the detailed analysis. The unbalanced dv/dt and the gate signal mismatch together result in the voltage imbalance of series-connected SiC MOSFETs and a set of new voltage balancing control methods are proposed. Passive capacitor compensation and closed-loop short pulse gate signal control are proposed to solve the voltage imbalance caused by the unbalanced dv/dt. Closed-loop gate delay time control is proposed to solve the voltage imbalance caused by the gate signal mismatch. Two gate driver prototypes are designed and verified for the proposed voltage balancing control methods. As the number of devices increases, the voltage balancing methods under the device-level will be complex and risky to coordinate. Therefore, the converter-level device voltage balancing methods are desired when over three devices are in stack. Therefore, this dissertation proposes to use the 3-level (3L) neutral-point-clamped (NPC) converter structure as a converter-level approach to simplify the voltage balancing control of series-connected SiC MOSFETs. A new modulation strategy is proposed to control the loss of clamping diodes, so compact MV SiC Schottky diodes can be selected to reduce the impact of extra components on the power density. Compared to the phase-leg with direct series-connected SiC MOSFETs, the phase-leg designed with the converter-level approach achieves similar power density, easier voltage balancing control, and better efficiency, which is attractive for both two and four devices in series connection. Finally, this dissertation studies the impact of series-connected 10 kV SiC MOSFETs on MV phase-leg volume reduction with the example of multi-level flying capacitor (FC) converters. The relation between the capacitances of FCs and the device voltage is studied and a new design procedure for FCs is developed to achieve minimum FC energy and regulate the maximum device voltage. With the design procedure, the total FC volumes of a 22 kV 5-level FC converter and a 22 kV 3-level FC converter with series-connected 10 kV SiC MOSFETs are calculated and compared. Series-connected 10 kV SiC MOSFETs are found to help significantly reduce the total FC volume (> 85 %). In summary, this dissertation demonstrates that the direct series connection of 10 kV SiC MOSFETs is a reliable solution for the MV converter design, and the converter-level approach is a better voltage balancing control method. This dissertation also presents a quantitative analysis of the volume reduction enabled by the series-connected 10 kV SiC MOSFETs in MV converter phase-leg design. / Doctor of Philosophy / Emerging industrial applications require medium voltage (MV) power converters. For existing MV converter solutions with Si IGBT, complex system structures are usually required, which affects the efficiency, power density, and cost of the system. For the design of MV converter, the recent 10 kV SiC MOSFET has the promising potential to improve efficiency and power density by adopting a simpler topology and fewer conversion stages. New design challenges also emerge with the new 10 kV SiC MOSFETs and one of them is the device voltage control during the operation. This dissertation mainly focuses on the voltage balancing control of series-connected 10 SiC MOSFETs, which is an attractive solution to build the MV converter phase-leg in a simple structure. Several voltage balance control methods are proposed and compared in this dissertation, which helps justify that the series-connected SiC MOSFET is a reliable approach for the MV converter design. In addition, this dissertation also analyzes the volume reduction enabled by the series-connected SiC MOSFETs with the example of a multi-level flying capacitor converter in dc-ac applications.

Rotor dynamics has become an integral part in the analysis and design of industrial turbo machinery. Rotor dynamics deals predominantly with the evaluation of the stability and damped critical speeds, and the response to an unbalance excitation, of turbomachinery. The majority of the industries which deal with rotor dynamics use the conventional and proven transfer matrix methods to solve the dynamics. However, the recent advances in computer technology and the distinct advantages of the finite element method make it an attractive tool to model complex rotor bearing systems. This research has developed a PC-based finite element analysis program capable of modeling rotors supported not only on fluid film bearings, but also on Active Magnetic Beatings (AMB). Methods are described by which the non-synchronous bearing properties can be used to evaluate the stability of the rotors supported on AMB. The effect of sensor noncollocation on general elliptic orbit response and stability has also been studied, as compared to the circular response of the existing programs. A design procedure for the stability of rotors supported on squeeze film dampers has been outlined. The unbalance response of rotors supported on squeeze film dampers can be predicted using the new iterative solution method which accounts for the nonlinear behavior of the damper. Multilevel analysis, essential for systems such as aircraft jet engines and certain other classes of turbo machinery, can be performed using this new computer program. A post processor for viewing/animating the damped mode-shapes and force:d response of a rotor, in 3-dimensions, has been developed. This ability to view the animated complex modes of forward, backward, and mixed forward-backward whirl of the rotor adds a new dimension in understanding the dynamics of rotating machinery. With the increasing demand for more accurately predicting the dynamic response and stability of high performance critical path turbomachinery, it is essential to develop advanced capability computer programs. The new PC-based finite element program developed in this research has the advanced capabilities required to model such complex rotating machinery. / Ph. D.