The 4-Stroke inverter topology is investigated and implemented in thisthesis as a method to damp the oscillation at the MOSFET drain-sourcevoltage when reverse recovery occurs. The aim is lower ElectromagneticInterference source level from the power inverter. The designprocess is coming from analyzing the appropriate inductor, making asimulation in LTSPICE and making a high-performance six-layer PCBfor the high current application. Finally, the prototype is tested in differentcontrol timing, radiated emission test and conducted emissiontest. / 4-taktsomvandlarens topologi undersöks och implementeras i dennaavhandling som en metod för att dämpa oscillation när reverse recoverysker i slutstegets MOSFET. Syftet är att dämpa elektromagnetiskstörning från kraftomvandlaren. Designprocessen är att analyseralämplig induktans, göra en simulering i LTSPICE och designa ett högpresterande6-lager PCB för kraftiga strömmar. Slutligen testas prototypenmed olika kontrolltider, elektromagnetisk emission och elektromagnetiskkonduktion.

In cancer research, studies on cells are often done in 2D, grown on plates which are not realistic. Therefore, a specialized system is being designed to build 3D cell structures. This system requires a fitting amplifier that is of low cost and changeable gain. The aim of this project was to design, simulate and build a custom amplifier circuit card, PCB, to be used in creating such an amplifier. At the end of the project the custom amplifier PCB should be connected with components such as power supply and should be able to take the place of the current one. The amplifier circuit was designed, and the simulations were tested, a finished design was created. Due to shortage of electronic components, the main IC component could not be acquired and hence a finished circuit could not be built. / Inom cancerforskning görs studier ofta på celler i 2D strukturer, plattor och detta är inte realistiskt. Därför utvecklas det ett nytt sätt att bygga cellstrukturer i 3D. Detta system kräver en anpassad förstärkare av låg kostnad och anpassningsbar förstärkning. Syftet med detta projekt var att bygga ett förstärkarkretskort. Inom metoden gjordes simulering, tester och utveckling av en krets samt bygge av ett förstärkarkretskort. Detta kort skulle kopplas till andra komponenter som nätaggregat och moderkort för att ersätta den nuvarande förstärkare. Simulering och design av krets gjordes men ett färdigt kort kunde inte testas på grund av leveransproblem av elektriska komponenter.

Avionics Division of Saab AB develops advanced electronics that need to be robust and work in harsh environments with for example extreme temperatures and cosmic radiation without any failure. To succeed with this the electronics need to be simulated and tested. Therefore this thesis work is done to strengthen the Avionics Division’s knowledge of hardware modelling and simulation by evaluating the simulation tools LTSpice, PSpice and SystemVision, their functions and capabilities. In this thesis a survey is carried out with help of a questionnaire to study the Avionics Division’s needs for simulation. The survey is underlying an analysis of the analyses that can be performed by the simulation tools for example Sensitivity analysis, Worst Case analysis, Monte Carlo analysis and Parametric Sweep analysis. The different analyses are discussed in the thesis. The questionnaire is also underlying an analysis of the tools LTSpice, PSpice and SystemVision. The result of the analysis is summarized in Table 1. A case study of a circuit simulation in SystemVision, based on an existing circuit used by Avionics Division, is also done within this thesis work. The study is done to evaluate the tool’s usability, to see if it is easy to perform a simulation and if it is easy to find and use suitable models from the model library. The case study describes how a simulation is performed in SystemVision and how an AC analysis of a Butterworth filter is done. A stability and reliability check of the tool is performed as well as a robustness simulation. The analyses were easy to do and the overall impression is that SystemVision is reliable and user friendly structured. In order to check and compare the results of the AC analysis the same analysis is performed using LTSpice. The comparison shows that the results differ. This depending on that the models of the circuit were some what different in LTSpice and SystemVision. The final conclusion is that SystemVision would fit within Avionics Division’s workflow. Using SystemVision demands education of the engineers to secure maximum use of all the advantages of SystemVision.

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In order to develop more economical and ecologically friendly transformers it is necessary to know the losses throughout the product development process. There are several losses related to transformers, but in this particular case the focus will be on the resistive loss of the transformer. In order to measure this loss first the resonant frequency of the transformer is determined. Since at resonance the secondary side of the transformer is considered to be purely resistive. The aim of this paper is to design and build a closed loop measurement system that is able to perform this task.

Detta projekt går ut på att skapa en analog effektpedal, från kretsdesign till montering på kretskort. Vi har designat en krets som förändrar en signal på ett sätt som bäst beskrivs som en phaser-pedal. Den ursprungliga signalen, tänkt att vara från ett elektriskt instrument, superpositioneras med en fasskiftad kopia. Fasskiftet görs genom fyra steg med allpassfilter, dessa lämnar amplituden oförändrad men fasskiftar beroende på frekvens. Hur mycket olika frekvenser fasskiftas regleras med Junction Field Effect Transistors (JFETs) som variabla motstånd. Fyra allpassfilter ger fullständig negativ interferens för två frekvenser, dessa kommer i rapporten refereras till som gropar. Groparna flyttas i frekvensspektrat över tid med hjälp av en lågfrekvensoscillator (LFO). Frekvensen på denna oscillator bestäms med ett variabelt motstånd och ligger mellan 0.1 och 10 Hz. LFO-signalen går in i Gate-kanalen på JFETsen och har en direkt koppling till deras resistans. Hela kretsen drivs av ett 9V-batteri och är designad för att behandla amplitudsspannet från elektriska instrument, från 1-1000mV. Kretsen ska inte heller förändra amplituden för någon frekvens mellan 41Hz och 20kHz. Kretsen har simulerats i LTspice, testats på kopplingsplatta och sist har ett mönsterkort skapats i KiCad där delarna lötts fast.

Today, there is a growing number of buildings in a neighborhood and business parks that are utilizing renewable energy generation, to reduce their electric bill and carbon footprint. The most current way of implementing a renewable energy generation is to use solar panels or a windmill to generate power; then use a charge controller connected to a battery bank to store power. Once stored, the user can then access a clean source of power from these batteries instead of the main power grid. This type of power structure is utilizing a single module system in respect of one building. As the industry of renewable power generation continues to increase, we start to see a new way of implementing the infrastructure of the power system. Instead of having just individual buildings generating power, storing power, using power, and selling power there is a fifth step that can be added, sharing power. The idea of multiple buildings connected to each other to share power has been named a microgrid by the power community. With this ability to share power in a microgrid system, a catastrophic event which cause shutdowns of power production can be better managed. This paper then discusses the data from simulations and a built physical model of a resilient microgrid utilizing these principles.

Usage of class D audio amplifiers has become increasingly widespread in recent years, mainly due to their high efficiency, which can reach almost 100 %. Class D amplifiers can also be compact, making them suitable for mobile applications. In contrast, the most efficient conventional amplifiers such as class B can reach a maximum efficiency of 78.5 %. The high efficiency of class D amplifiers can be attributed to the switching stage, which in the case of a half-bridge design consists of two amplifying MOSFETs. These MOSFETs are never on at the same time, which minimizes the quiescent current and thereby the power losses. The goal of this project was to design, simulate and construct a half-bridge class D audio amplifier. A working amplifier with 80 % efficiency was built, with power losses occuring mainly in the voltage regulators. Simulations of the amplifier corresponded well with the constructed amplifier apart from issues originating from the aforementioned voltage regulation as well as the triangle wave generator. The goal of the project was achieved and the finished amplifier possessed good sound quality and little unwanted noise. To further improve on the design, better voltage regulation, a full-bridge configuration and a feedback loop could be utilized.

The rise of batteries in the industry, especially Li-ion, is increasing rapidly. Li-ion battery systems are traditionally composed of a particular type of cell chemistry fit to the system needs. Due to the significant differences between chemistries, different cells have different attributes. The thesis explores the potential of a heterogeneous solution to include different cells to find a suitable compromise between different attributes. An electrified passenger train using a homogenous solution was evaluated against a heterogeneous solution consisting of two cell types, NMC and LTO, which have significant differences in attributes.  Simulation with models covering the train kinematics, track characteristics, and battery behaviour generates the thesis results. Validation of simulation results includes comparing previous simulations and the new effects of the heterogeneous solution, which indicate a good fit. Verification of the results encompasses a small-scale experiment with a custom-made physical circuit to observe the proposed solution's actual behaviour and verify model validity, which implies the correctness of models and implementation. The results indicate that a heterogeneous solution is possible within the scope of electrified trains. Furthermore, several trade-offs exist between NMC and LTO cells, especially regarding rate capability, safety and capacity, which confirms the potential of heterogeneous battery systems.