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Active Thermal Control of Power Semiconductor for High Power Electric Drive Applications
(2024) Yesgat, Amare; Chalmers tekniska högskola / Institutionen för elektroteknik; Liu, Yujing; Sharma, Nimananda
Abstract Electric vehicle applications, driven by the need for space and mass savings, increasingly demand high-power density inverters. However, this reduction in mass has led to a decrease in thermal capacity, badly exposing power emiconductors to larger temperature swings and thermal cyclic stress. The vulnerability of wire bonds and chip solder in the power semiconductor to failure due to thermal cycling necessitates a solution. This solution, actively controlling the junction temperature during operation, is the focus of this research and is referred to as active thermal control techniques (ATC). Different active thermal control strategies are explored in the literature via manipulation of losses or heat dissipation and they are discussed in this work. Some of the methods require specific hardware, such as specialized gate drivers. The control of junction temperature without any extra hardware can be achieved by controlling the PWM frequency, load current, and modulation methods. However, controlling load current requires implementing an online current reference estimation. Additionally, changing the modulation method would increase control complexity. Therefore, this work investigates active junction temperature control by varying the PWM frequency. The junction temperature is controlled using a hysteresis band-type controller with some modifications. The influence of the control band and average junction temperature calculation on the inverter’s control effectiveness, prolonged lifetime, and improved efficiency is investigated. The inverter’s losses are calculated analytically, and the inverter is implemented together with a heavy-duty truck and machine model in simulations. Drive cycle-based analysis is combined together with rain flow counting and a lifetime model to estimate the influence of the controller on the devices’ lifetime. Simulation results show that the active control of the junction temperature can result in more than 246% increase in lifetime and simultaneously increase efficiency by 0.30%.
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Utveckling av 3D-printad funktionsmodell av flygmotor
(2024) Brink, Lina; Christensson, Felix; Hemå, Petter; Karlsson, Fabian; Lundkvist, Vera; Wäpling, Alfred; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Isaksson, Ola; Martinsson Bonde, Julian
In today’s society the environment has gained much attention, causing more and stricter regulations to be set regularly regarding aircrafts and their fuels. Emissions need to be minimized while transports need to get longer and faster. That is why this area is under continuous development, requiring updated information and educational tools that can aid visualizing modern and future concepts. Physical models are required to visualise the developments made, which has therefore been one of the main goals of this project to produce. A literary study has been made to collect information regarding common commersial aircrafts and fuels, as well as the most popular concepts for the near future. These concepts have then been compared and their advantages and disadvantages explored. A physical model has been created based on the information to show differences and similarities, as well as the function of different configurations of turbofan engines. This model specifically show differences regarding bypass and gears, among other things
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Möjlighetsstudie av en sond stor som en burk
(2024) Christoforidis Johansson, Kevin; Dalevi, Alice; Gustavsson, William; Niens, Patrik; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Bergsjö, Dag Henrik; Bergsjö, Dag Henrik; Xisto, Carlos
This project was based on the American competition CanSat, where every team was tasked with creating a can-sized satellite to launch with a rocket. The task in this specific case was to study the feasibility of developing a satellite based on the dimensions of an American 355ml can, without the actual rocket launch. Using ”trial and error” as the primary approach for mechanical design was established early on and complemented by the integration of Arduino for electrical systems and sensors. Basic theories in fluid mechanics and mechatronics were also utilized. Every subsystem was tested individually, to ensure they worked as intended. The final prototype did reach a mostly satisfactory result with some subsystems not fulfilling the requirements set prior to the tests. Other subsystems were left out, due to time constraints. Overall, the project showed that it is feasible to create a can-sized satellite. However, more time and resources would be needed to reach a product that complies entirely with the requirement list and can partake in the actual competition.
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Utveckling av Slitagetålighetstest för Plastdetaljer
(2024) Dalal, Ali; Honauer, Ludwig; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Boldizar, Antal; Boldizar, Antal
The purpose of the project was to investigate, plan, and, as far as possible, implement a method for evaluating the abrasion resistance of plastic in collaboration with the company FlexLink. Currently, FlexLink uses a method for evaluating abrasion resistance that takes 500–2000 hours to yield results. Our goal was to reduce this time to only 24–72 hours. Specific material choices were not included in the project as the focus was on developing a preliminary method for the materials currently in use. The project began with information gathering and study visits to RISE in Mölndal and Borås for detailed knowledge acquisition on the subject. Subsequently, a selection of methods was made to determine the method with the best potential to meet the objective. The chosen method was the “Pin on Ring” method. This is a modified version of “Pin on Disc,” which is currently used by FlexLink and RISE for material testing. Since the method is based on the existing method, several concept development stages were needed to produce a final product. Finally, CAD models and a rig construction were created to visualize the method. However, implementation could not be completed due to the lack of several critical components needed to build the equipment and thus validate and compare it with the existing method.
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Materialval i VA-system baserat på miljöoch klimataspekter samt anläggning-, driftoch underhållskostnader
(2024) Carlsson, John; Vainio, Axel; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Persson, Christer
This thesis was commissioned by Växjö Kommun and aims to investigate the three sustainability dimensions in relation to different materials and their role in the water and sewage industry. Växjö Kommun seeks more data to support their material selection decisions in projects, as current decisions are sometimes based on personal opinions. The materials explored include PE and ductile iron in pressure pipelines, PP, PVC, and concrete in gravity pipelines, and PP and concrete in two types of wells. The ecological sustainability dimension has been analyzed through quantitative calculations based on EPD studies and LCA conducted for the various products, as well as discussions on environmental perspectives with municipalities. Since not all aspects are included in the product environmental declarations, the analysis only covers the production stage, with values for the materials also sourced from Granta EduPack. The economic sustainability dimension has been investigated by analyzing damage history and consulting with knowledgeable individuals from Gothenburg, Kalmar and Växjö who work with damage frequency, damage history, and costs related to these damages. The social sustainability dimension has been examined through interviews with individuals from three different municipalities, focusing primarily on differences in working conditions when using different materials. The results show that there are ecological differences between materials but that it should be further explored as only a small part of the entire life cycle has been able to be analyzed for all products, EPD-studies were also missing for certain well-components and other products that would have been relevant to compare. The interviews reveal that some municipalities currently do not consider environmental aspects when selecting materials for piping. From an economic perspective, more resources are required to accurately determine all cost differences throughout the products' life cycles. Regarding working conditions and other social aspects, there should be no significant differences if the work is carried out correctly, even though the work processes may vary depending on the material chosen.