Chalmers Open Digital Repository

Välkommen till Chalmers öppna digitala arkiv!

Här hittar du:

Studentarbeten utgivna på lärosätet, såväl kandidatarbeten som examensarbeten på grund- och masternivå
Digitala specialsamlingar, som t ex Chalmers modellkammare
Utvalda projektrapporter

Forskningspublikationer, rapporter och avhandlingar hittar du i research.chalmers.se

Enheter i Chalmers ODR

Välj en enhet för att se alla samlingar.

Visar 1 - 2 av 2

Senast publicerade

Power Management Strategy for Islanded Operation Using Wind Power, Solar PV, and Battery Storage
(2026) Jinu, Albi; Motty, Abhimanyu
As electricity demand grows and renewable energy becomes a larger part of the power system, maintaining a reliable supply during grid interruptions becomes increasingly important. Microgrids that combine wind power, solar photovoltaics and battery storage can supply local loads independently of the main grid. However, operating these systems in islanded mode requires careful coordination to balance changing generation and demand. This thesis investigates the islanded operation of a wind–solar–battery microgrid based on the Chalmers research wind turbine at Björkö, Sweden. A battery-connected grid-forming converter provides the voltage and frequency reference, allowing wind and solar generation to operate alongside it through grid-following converters. The main objective was to develop a power balance controller and evaluate its ability to work with the grid-forming converter during different operating conditions. The control logic was developed in MATLAB/ Simulink to manage power surpluses and deficits while respecting battery state-of-charge and power limits. When renewable generation exceeds demand, the controller directs the surplus to the battery and curtails generation when necessary. When generation is insufficient, the battery supplies the shortfall, with load shedding used when the available power cannot meet demand. EMTP-RV simulations were then used to evaluate the interaction between the power balance controller and the grid-forming converter. The simulation results demonstrate how coordinated control of generation, storage and demand can support islanded operation within the system’s operating limits. The work provides a basis for developing renewable microgrids that can maintain local electricity supply when disconnected from the main grid.
Arcturus Design och konstruktion av en vektorstyrd modellraket
(2026) Bergstedt, Frode; Eklind, Tilde; Enell, Anton; Gustafsson, Victor; Randerz, Viggo; Richardt, Christian
The goal of the project was to design and build a thrust vector controlled (TVC) model rocket, with an aim to stabilize the rocket with active control. The aim was split into three parts: (1) simulation; (2) static test with free rotation; and (3) free launch. To comply with Swedish laws, the rocket was restricted to maximum weight of 500 g, with a maximum 100 g reserved for propellant. With these design limitations in mind, the rocket body and systems for both the electronics, TVC, and parachute were custom made, with the goal to minimize weight. The designed rocket weighed a total of 499,2 g with propellant. However, parts like the custom flight computer did not work as intended, thus a new makeshift solution was required for launch. After the rocket was designed and built, three static test launches and one live flight were executed. Even though the simulations gave promising results, none of the launches proved successful. This could be due to a discrepancy between simulation and reality. In the end, the goal was achieved, but the aim failed on all three parts, which could have been remedied by a longer research and development phase.
Automatic Segmentation of the Pectoralis Major Muscle in Magnetic Resonance Imaging Using nnU-Net: Evaluation of Training Mask Modifications and Anatomical Thickness Measurements
(2026) Emteborg Dabrio, David
Computational human body models (HBMs) can improve vehicle safety research by accounting for anatomical variability that is difficult to capture using traditional crash testing methods. Statistical shape models (SSMs) provide a means of representing this variability using medical imaging data, but their development requires accurate and reproducible anatomical segmentations. This thesis investigated the feasibility of automated segmentation of the pectoralis major muscle from magnetic resonance imaging (MRI) data using the nnU-Net framework. To the best of our knowledge, automated segmentation of the pectoralis major muscle from MRI data has not previously been investigated. The applicability of the segmentation methodology to other muscles was not evaluated and therefore remains to be investigated. Eleven manually segmented subjects from the TotalSegmentator MRI dataset were used to train and evaluate three training datasets: the original manually segmented masks (Nominal), masks systematically contracted by one voxel layer (Contracted), and masks systematically expanded by one voxel layer (Expanded). This comparison was performed to investigate how systematic modifications of the training masks affected pectoralis major segmentation performance. In addition, a repeatable landmark-based methodology was developed for measuring pectoralis major muscle thickness from the manually segmented MRI data, providing an initial anatomical baseline for future statistical shape modelling. The results indicate that the use of nnU-Net for automated segmentation of the pectoralis major muscle is feasible; however, due to the limited amount of available data, a highly accurate model could not be trained. The Expanded dataset produced slightly improved average segmentation performance compared with the Nominal dataset, whereas the Contracted dataset resulted in poorer performance. However, the differences between the Nominal and Expanded datasets were small relative to the variation between subjects, indicating that anatomical variability and limited dataset size had a greater influence on segmentation performance than the systematic mask modifications. The proposed pectoralis major segmentation and thickness measurement methodologies provide a foundation for future work on statistical shape models and human body models for vehicle safety applications.
Utveckling av ett Excelbaserat dimensioneringsverktyg för mellanspänningsdrivsystem
(2026) Abbas, Abdullah; Ahmed, Mohammad
Industriella mellanspänningsdrivsystem blir allt mer komplexa, vilket skapar ett behov av tydliga och tillförlitliga metoder för dimensionering i tidiga projektfaser. I många projekt baseras valet av omriktare och tillhörande utrustning, såsom transformatorer, ofta på information från olika tekniska dokument tillsammans med tidigare erfarenhet. Detta kan göra processen tidskrävande och leda till variationer i hur beslut fattas. Detta examensarbete fokuserar på utvecklingen av ett Excel-baserat dimensioneringsverktyg som stödjer val av mellanspänningsomriktare och hjälper till att definiera lämpliga transformatorlösningar. Verktyget är avsett att användas i tidiga projekt- och offertskeden, där beslut ofta behöver fattas inom begränsad tid men ändå baseras på ett tillräckligt tekniskt underlag. Genom att kombinera elektriska beräkningar, produktdata, derating-faktorer och frekvensberoende driftförhållanden samlas dimensioneringsprocessen i ett strukturerat arbetsflöde. En viktig del av arbetet är att transformatorns specifikation inkluderas som en del av valet av omriktare. Utifrån de systemkrav som användaren anger kan verktyget generera ett strukturerat transformer inquiry data sheet och indikera om en standardtransformator är lämplig eller om en kundanpassad transformator krävs. På så sätt kopplas den tekniska dimensioneringen tydligare till praktiska ingenjörsbeslut i projekt- och offertarbete. Microsoft Excel valdes som plattform eftersom det är lättillgängligt, välkänt för många ingenjörer och gör beräkningar och antaganden transparenta. Även om Excel har begränsningar jämfört med mer avancerade simulerings- och designverktyg ger det en praktisk balans mellan funktionalitet och användbarhet i tidiga skeden. Resultatet visar att ett strukturerat dimensioneringsverktyg kan göra urvalsprocessen mer enhetlig och minska beroendet av enskilda personers erfarenhet. Verktyget kan även bidra till snabbare och mer organiserat beslutsfattande i projekt- och offertarbete. Samtidigt bör det ses som ett stöd för preliminära tekniska analyser och inte som en ersättning för detaljerad projektering, slutlig verifiering eller projektspecifik teknisk granskning.
Robust Vehicle Acceleration Control
(2026) Kongstad, Alexander; Karlsson, Fabian
This thesis investigates robust acceleration control for heavy-duty vehicles to improve longitudinal control and driver-assist functions. Despite advances in longitudinal vehicle control, important limitations remain. Existing control strategies may be sensitive to measurement delays, perform poorly for small acceleration errors, and insufficiently reject oscillatory disturbances from driveline windup and tire dynamics. These challenges motivate a model-based control approach that explicitly accounts for the relevant system dynamics to improve tracking performance and disturbance rejection. A third-order state-space driveline model was developed to capture the system’s dominant dynamics, including flexible driveshaft behavior modeled as a springdamper system. The model was tuned and validated against real-world measurements from a battery electric vehicle (BEV), demonstrating close agreement in both speed and acceleration responses across multiple driving scenarios and gear configurations. A Smith predictor was subsequently designed and evaluated to compensate for the system’s inherent dead-time delays. Simulation testing showed that the Smith predictor maintains stability under model and delay mismatches of up to ±50%, while also enabling higher controller gains and faster response times. To further improve performance, the Smith predictor was extended to include measurement updates. An LQG controller with integral action, focusing on robustness properties, was proposed to address driveline oscillation damping and steady-state tracking accuracy. Simulation results show that, given an accurate model, the proposed controller reduces oscillations and improvesmproved steady-state tracking compared to the current controller. Using logged vehicle data, the simulation validated the proposed controllers, showing that model-based control strategies can improve acceleration-tracking performance and robustness compared to the existing controller.