Examensarbeten för kandidatexamen // Bachelor Theses

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https://odr.chalmers.se/handle/20.500.12380/54

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Är det is eller vatten? - en studie i att bestämma vattnets fas med hjälp av simulationer och flervägsreflekterade GPS-signaler
(2013) Hansson, Mathias; Sundberg, Joakim; Martinsson, Daniel; Alping, Mikael; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
Havsisars utbredning är något som skiljer från år till år och som är beroende av ihållande temperatur under 0. Genom användning av MATLAB, SNR-data från mottagna GPS-signaler och med hjälp av simulationer har olika parametrar som kan underlätta bestämmandet av havsisens utbredning analyserats. En metod för att automatiskt kunna avgöra vattnets fas har utvecklats. Under de dagar som den insamlade mätdatan avser, var det möjligt då man först valde ut en lämplig satellit, att avgöra om det var vatten eller is.
Design och konstruktion av ett energieffektivt spårbundet fordon för deltagande i studenttävlingen Delsbo Electric
(2016) Ödman, Daniel; Yring, Ulrika; Bergstedt, Elin; Reckermann, David; Larsson, Carl; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
The student race Delsbo Electric 2016 is held 28th of May. The race consists of a course of 3.36 km which is a part of Dellenebanan. The aim of this race is to travel this course and consume the least possible amount of energy per person and kilometre. In 2015 the energy consumption was measured to 1.26 watt hours per person and kilometre [Wh/pkm] for the winning team. This project is a bachelor thesis at the department of Energy and Environment at Chalmers University of Technology and aims to design an energy efficient rail bound vehicle to participate in the race. This project is supposed to be repeated yearly, and the following students should be able to improve from this project. To be able to create an energy efficient vehicle, a specification was made which consisted of requirements that the vehicle had to fulfil. The foundation to the design and different components of the vehicle consisted of simulations and theoretical models. The simulations were also used to estimate the vehicles energy consumption. The function of the finished vehicle was tested and the real energy consumption was measured during a test run. The energy consumption was later compared to the simulated values to evaluate if the simulations were made correctly. The vehicle moved steadily on the rails during the test run, and was able to get through the rail switch which was a demand since a switch appears on the race course. The energy consumption at the test run was measured to 1.76 Wh/pkm. The simulation of the test run resulted in 1.82 Wh/pkm when assumptions of completely flat ground was made. However, small variations in the inclination did effect the energy consumption in the simulations distinctly. This project resulted with a vehicle that fulfils the specifications which enables the project group to participate in the race. The energy consumption was, using the simulations tools, estimated to 3.4% deviation from the test run. This estimate is though unsure due to unknown parameters during the test. For the students that will further develop the vehicle the following years, there are many ways to improve the energy efficiency of the vehicle. It is first and foremost the weight of the vehicle that can be cut, but one could also increase the number of passengers on the vehicle to improve the energy efficiency. Constrains that were of significant value to this project were that the energy efficiency did not have any demands to result in a first place in the race. This constraint is set because the experience within the project group is far less then compared to schools that have been participating earlier years. No results from the race will be presented, due to the fact that the date of the race takes place after the report’s completion.
Havsnivåmätningar med hjälp av fl ervägsrefl ekterade GPS- och GLONASS-signaler
(2013) Bermell Rudfeldt, Mattias; Torgnyson, Otto; Johansson, Annika; Hermansson, Daniel; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
Att kartlägga havsnivåförändringar är en stor del av att bevaka klimatförändringar på jorden. Den lokala havsnivån är mycket viktig för kustnära samhällen. I dagsläget mäts lokal havsnivå med en för ändamålet specialanpassad teknik, mareografer. Mareografer är fästa på berggrunden vilket gör att deras mätningar påverkas av landhöjningen. I detta arbete studeras en ny teknik för havsnivåmätning som använder redan existerande kustnära Global Navigation Satellite System (GNSS)-installationer. Dessa stationer är installerade för att mäta landrörelse, men påverkas av flervägsreflektioner från havsytan. Utifrån signalbrusdata från GNSS-signaler inspelade vid dessa mätstationer kan havsnivån beräknas lokalt. Denna studie har utförts vid en installation vid Onsala rymdobservatiorium och använt signaler från amerikanska Global Positioning System (GPS) och ryska Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS). Den beräknade havsnivån har jämförts med mätningar från mareografer, i form av trycksensorer, på samma plats. Havsnivån från GPS- och GLONASS-signaler visar hög korrelation vid jämförelse med trycksensorena. Avvikelsen, beräknad som ett root-mean-square (RMS), mellan mareografdata och GPS-mätningar är endast 4.67 cm och för GLONASSmätningar ännu lägre, 4.12 cm. Då de båda resultaten kombineras uppnås fler mätpunker vilket ger tekniken bättre förutsättningar för platser med snabba havsnivåförändringar. Den kombinerade mätningen ger ett RMS-värde gentemot mareografdata på 4.12 cm. Det indikerar att tekniken att kombinera mätningar har goda framtidsutsikter.
Induktiv energiöverföring för laddning av batteri i ett mobilt arbetsbord
(2016) Lensfors, Kajsa; Anderberg, Martin; Nilsson, Albin; Trillkott, Johanna; Hellgren, Isak; Bäckstrand, Albin; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
This bachelor thesis aims to construct a system for wireless charging of a battery by means of inductive energy transfer. At the request of the company ErgoMedical AB, a prototype has been constructed which is supposed to be mounted on a worktable to charge its battery with 300 W at 48 V. The prototype is supposed to ease the work of healthcare workers who use the worktable by removing the cable otherwise needed to charge the battery. The goal is to reduce the risk of battery depletion. The system consists mainly of a receiver coil, a transmitter coil, a compensation network and a rectifier. The radiuses of the coils were determined on the basis of simulations in COMSOL Multiphysics, where the receiver and transmitter coil radiuses were determined to 10 cm and 13 cm. The number of turns were set to 9 and 16 respectively, given the use of ferrite. The coils were constructed using litz wire and placed a distance of 5 cm apart in a respective frame of plastic. The compensation network was chosen using theory along with simulation in Pspice to a series-series compensation network, which showed satisfying results through tests in regards to the systems requirements. Finally, the project resulted in an operating prototype with an efficiency of 91.4% while mounted on the worktable. In addition, the system proved through simulations to be robust against misalignment. With a suitable control system, this prototype could very well be developed into a functioning product for future use in healthcare environments.
Konstruktion av hoverboard med elektrodynamisk suspension
(2016) Malm, Calle; Larsson, Philip; Jägerhag, Charlie; Eriksson, Paulina; Jacobson, Nils; Claeson, Viktor; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
This project was conducted to determine whether it was possible to construct a hoverboard utilizing electrodynamic suspension. This was accomplished by testing the affecting input variables during attempts to provide a vertical force using coils. The results of the experiments was then used to optimize one coil for maximum lift, which was then duplicated and mounted on a board. The conclusion was that it is theoretically possible to scale up the project to carry one person, even though the final prototype only was capable of lifting 16 kg.
Singing Arc - Konstuktion av en tongenererande teslaspole
(2017) Poposki, Daniel; Marne, Michael; Höglund, Nils; Falk, George; Loftman, Victor; Blomkvist, Niklas; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
A muscial tesla coil is a form of transformer which at high frequency transforms a low primary voltage into a considerably higher secondary voltage that results in discharges. These discharges can be modulated into musical tones by turning on and off the tesla coil with the frequency of the tones. In order to construct a musical tesla coil with variable discharge rate a Dual Resonant Solid State Tesla Coil was created. The resonant frequency of the primary circuit was matched to the frequency of the secondary circuit, which was measured to 121kHz. This was achived by the usage of capacitors connected in series with the primary coil. The primary coil was shaped as a flat Archimedian spiral with the ability of frequency tuning by moving its variable connection point. The resonant frequency signal was generated by a Phase Locked Loop, which received the oscillation frequency from the tesla coil through an antenna and created a square wave with the same frequency. The resonant frequency was combined, through a network of AND-gates, with the tone signal from an Arduino, which in turn was controlled by a software client written in C#. The client decoded .midi-files into an array of tones whose frequency was sent to the Ardunio. The Arduino shut off and turned on the tesla coil with the same frequency as the tone and thus creating an audible tone. An H-bridge was utilized to create an AC-voltage using the control signal together with a DC-source. The ampacities of the H-bridge was however the limiting factor of the magnitude of the discharges which could be generated. At 100A through the primary coil, electrical discharges of 11.5cm in length could be generated which could play musical pieces.
Test och implementering av en laserbaserad havsnivåmätare
(2016) Börjesson, Erik; Jansson, Julia; Johansson, Carl von Rosen; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
Measuring sea level has been of interest in Sweden since the discovery of the land uplift and today one reason for measurements is the current climate change. By accurately measuring the sea level, vulnerable coastlines can be detected at an early stage and appropriate measures can be taken. The two types of sensors, radar and pneumatic bubbler gauge, that are mounted at the tide gauge well at Onsala Space Observatory both have a best case measurement uncertainty of 3 mm. This report will study another method based on an optical distance sensor, a laser, that will be a complement to the other two. Before an implementation of such an optical distance sensor the devices accuracy have to be examined. Given the specifications of the wells dimensions measurements related to repeatability, linearity and temperature depence will be carried out. The report conclude that an optical distance sensor has the smallest standard deviation of the three sensors, based on an experiment lasting slighly longer than one day, and that no significant temperature dependence can be found. The laser will sample the reflected light from a reflector that floats on the water surface. Calculations show that this reflector has insignificant impact on the total measurement accuracy. Therefore an optical distance sensor is a useful alternative to the already mounted sensors at Onsala Space Observatory for measuring the sea level.
Undersökning av det elektriska systemet för tidvattenkraftverket Deep Green i spänningsintervallet 500V till 3,3kV
(2016) Nilsson, Simon; Engström, Petter; Ellström, Andreas; Karlsson, Rasmus; Rydegård, Andreas; Antonsson, Daniel; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
With today’s need for renewable energy new technologies needs to be developed to meet this demand. Minestos concept for the tidal power plant Deep Green is one such technology. Deep Green is a power plant that with its unique movement pattern extracts energy from tidal currents that previously have been untapped. In this project the electrical system of Deep Green is studied and what the effects are for a rise in operating voltages from 500V to 690V , 1kV and 3, 3kV . The procedure for this project is a literature study in connection with simulations with the programs Matlab, Comsol and Pspice. The results show that an increased voltage to 690V will lead to the power loss being reduced by half in the submarine cable. The higher voltage leads to a fractional change of the power electronics in the system. The conclusion of this study is that a heightened voltage level that gives lower losses is favorable. To implement the voltages 1kV and 3, 3kV further investigations are required because several components needs to be replaced or modified at these voltage levels.
Utvärdering av en mer förnyelsebar elproduktion i Sverige
(2017) Alihodza, Admir; Fahlgren, Anton; Hamidovic, Mirza; Tauson, Niclas; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
As renewable electricity generation becomes more in demand on the market, the task of producing electricity without interruptions grows more complicated. Conditions like hours of sunshine and wind speed to supply solar and wind power plants cannot be accurately predicted or controlled. In order to maintain a reliable power supply, the supply network must be adapted if the expansion of these types of production is to be sustainable. The purpose of this report is to describe the approach to investigate and visualize how the Swedish electricity system is affected by the introduction of more renewable electricity generation. This has been done by studying a larger collection of scientific literature evaluated for its relevance and reliability, which has then been compiled into this report. After that, a model has been designed and integrated with a web interface to simulate and visualize Sweden's electricity supply. The results from the model show that large power reserves will be needed in the power system in order to compensate for the lack of power when wind and solar power conditions are less than desirable. In addition to power reserves, the deficiency can be addressed by expanding the transmission capacity in the Swedish grid, alternatively, power can be imported from neighboring countries. In conclusion, an exclusively renewable electricity generation without nuclear power is possible, but today's power grid needs to be expanded and developed to compensate for an increasingly unpredictable power generation.

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