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The LLC resonant converter has been widely used as a DC-DC converter due to its high efficiency, high power density and hold-up capability in power supplies for communication systems, computers and consumer electronics. Use of the high-frequency LLC converter has also been increasing in recent years due to its high power density and integrated magnetics, which reduce the total cost. With the fast development of wideband gap devices and novel magnetic materials, the trend of pushing switching frequency higher continues. However, the control characteristics of the LLC resonant converter are much more complex than that of the PWM converter due to the dynamics of the resonant tank. This paper employs state-trajectory analysis to describe and analyze the behavior of the resonant tank. Control methods based on state-trajectory analysis were used to solve the challenges in the control of the LLC resonant converter, including unpredictable dynamics, burst mode for light-load efficiency, soft start-up and short circuit protection. Additionally, digital controllers are gradually taking the place of analog controllers in the control of the LLC resonant converter due to the advantages of the digital controllers over the analog controllers, such as their ability to be flexible and re-configurable, capable of non-linear control, and able to communicate with other controllers. Among the digital controllers, cost-effective microcontrollers (MCU) are preferred for industrial applications. Because of the advantages of the state-trajectory control and the industrial preference in the cost-effective digital controllers, it would be of great benefit to apply state-trajectory control to high-frequency LLC converters with cost-effective digital controllers. This thesis investigates the impact of digital delay on state-trajectory control. Simplified Optimal Trajectory Control (SOTC) for LLC converters is further simplified so that SOTC can be achieved with cost-effective digital controllers. Furthermore, the limitations caused by digital controller are explained in detail, and methods are proposed to apply the SOTC to high frequency LLC converter is proposed. A detailed analysis of fast load transient response, soft start-up, burst mode for light-load efficiency and synchronous rectification (SR) driving is provided. Multi-step SOTC for fast load transient response is proposed to apply cost-effective digital controllers to high-frequency LLC converters; SOTC for soft start-up with only sensing Vo is proposed to minimized the impact of digital delay on state-trajectory control; SOTC for burst mode with multi-step is proposed to eliminate the limitation of minimum off-time caused by digital controllers in constant burst-on time control; a generalized adaptive SR driving method using the ripple counter concept is proposed to significantly reduce controller resource utilization for the SR control of high-frequency LLC converters. The whole control system is demonstrated on a 500kHz 1kW 400V/12V LLC converter with a 60MHz MCU, which integrates all the proposed control methods. / Master of Science

Yes / This article presents a novel four-dimensional autonomous fractional-order chaotic system (FOCS) with multi-nonlinearity terms. Several dynamics, such as the chaotic attractors, equilibrium points, fractal dimension, Lyapunov exponent, and bifurcation diagrams of this new FOCS, are studied analytically and numerically. Adaptive control laws are derived based on Lyapunov theory to achieve chaos synchronization between two identical new FOCSs with an uncertain parameter. For these two identical FOCSs, one represents the master and the other is the slave. The uncertain parameter in the slave side was estimated corresponding to the equivalent master parameter. Next, this FOCS and its synchronization were realized by a feasible electronic circuit and tested using Multisim software. In addition, a microcontroller (Arduino Due) was used to implement the sug-gested system and the developed synchronization technique to demonstrate its digital applicability in real-world applications. Furthermore, based on the developed synchronization mechanism, a secure communication scheme was constructed. Finally, the security analysis metric tests were investigated through histograms and spectrograms analysis to confirm the security strength of the employed communication system. Numerical simulations demonstrate the validity and possibility of using this new FOCS in high-level security communication systems. Furthermore, the secure communication system is highly resistant to pirate attacks. A good agreement between simulation and experimental results is obtained, showing that the new FOCS can be used in real-world applications.

In connection with rising urbanization and more people deciding to live in cities the opportunity to cultivate plants decreases. Indoor gardening still tends to be a popular hobby. Because the flower and plants don’t get natural sunlight and water from rain, maintenance is required. A problem that may arise in the event of a longer absence is to cater for the plants watering needs. The purpose of this project was to create an automatic irrigation system that distribute water to the plants and flowers in order to maintain a predetermined moisture percentage in the soil. This was archived by using moisture sensors. Tests were conducted on the irrigation systems different components and the results shows that a track guided water delivery system is both accurate and durable, however with a lot of moving parts there is an increasing risk of malfunction. / I samband med urbaniseringen där fler människor bestämmer sig för att bo i storstan minskar många gånger möjligheterna till odling av växter. Odling inomhus tenderar ändå att vara en hobby för många. Eftersom blommor och växter inomhus inte får naturligt solljus och vatten från regn krävs det ett visst underhåll från odlaren för deras överlevnad. Svårigheten vid en längre frånvaro är bland annat att tillgodose växternas vattenbehov. Syftet med detta projekt var att skapa ett automatiskt bevattningssystem som distribuerar vatten till växter och blommor med syftet att bibehålla en bestämd fuktighet i jorden. För detta användes fuktsensorer. Tester utfördes på bevattningssystemens olika komponenter och resultatet visar att ett spårstyrt vattentillförselsystem är både tillförlitlig och hållbart, men med många rörliga delar ökar risken för funktionsfel.

This thesis presents the implementation of some of the basic concepts of digital logic design in a fun and creative way with the help of paper electronics. This involves circuit building on paper using conductive tape or conductive ink and circuit components as electronics craft materials. Paper electronics toolkit called circuit sticker microcontroller which is deployed by a company named Chibitronics and AT89C51 microcontroller were used for the computational functioning of the circuits built on paper. This can be used to teach the fundamentals of digital logic design to the students in their early stage of studies in an attractive way and can help them them gain a better understanding. This thesis can also be helpful in grabbing the attention of high school students and motivate them towards choosing the engineering discipline for their higher studies.

This thesis presents the development of soft- and hardware for a high-throughput prism-based Total Internal Reflection Fluorescence (pTIRF) microscope. By re-purposing components from various sources, most notably from an Illumina sequencer, the project details the build and integration of necessary components for the microscopy platform. This pTIRF setup aims to enable high-throughput quantitative binding measurements between biomolecules by combining the sensitivity of TIRF microscopy with the scalability of sequencing technology. The project details the construction process, experimental setup, and potential applications of the developed platform. / Projektet beskriver utvecklingen av mjuk- och hårdvara för ett high-troughput prismabaserat Total Internal Reflection Fluorescence (pTIRF) mikroskop. Genom att återanvända olika komponenter, framför allt från en Illuminasekvenserare, behandlar projektet tillverkning och integrering av nödvändiga komponenter för mikroskopiplattformen. Denna pTIRF-uppställning ämnar utföra high-throughput kvantitativa bindningsmätningar mellan biomolekyler genom att kombinera känsligheten hos TIRF-mikroskopi med skalbarheten hos sekvenseringsteknologi. Uppsatsen beskriver byggprocessen, det experimentella upplägget och de potentiella tillämpningarna av den utvecklade plattformen.

In this thesis a design for a smart high efficiency voltage regulating module capable of supplying the core of modern microprocessors incorporating dynamic voltage and frequency scaling (DVS) capability is accomplished using a RISC based microcontroller to facilitate all the functions required to control, protect, and supply the core with the required variable operating voltage as set by the DVS management system. Normally voltage regulating modules provide maximum power efficiency at designed peak load, and the efficiency falls off as the load moves towards lesser values. A mathematical model has been derived for the main converter and small signal analysis has been performed in order to determine system operation stability and select a control scheme that would improve converter operation response to transients and not requiring intense computational power to realize. A Simulation model was built using Matlab/Simulink and after experimenting with tuned PID controller and fuzzy logic controllers, a simple fuzzy logic control scheme was selected to control the pulse width modulated converter and several methods were devised to reduce the requirements for computational power making the whole system operation realizable using a low power RISC based microcontroller. The same microcontroller provides circuit adaptations operation in addition to providing protection to load in terms of over voltage and over current protection. A novel circuit technique and operation control scheme enables the designed module to selectively change some of the circuit elements in the main pulse width modulated buck converter so as to improve efficiency over a wider range of loads. In case of very light loads as the case when the device goes into standby, sleep or hibernation mode, a secondary converter starts operating and the main converter stops. The secondary converter adapts a different operation scheme using switched capacitor technique which provides high efficiency at low load currents. A fuzzy logic control scheme was chosen for the main converter for its lighter computational power requirement promoting implementation using ultra low power embedded controllers. Passive and active components were carefully selected to augment operational efficiency. These aspects enabled the designed voltage regulating module to operate with efficiency improvement in off peak load region in the range of 3% to 5%. At low loads as the case when the computer system goes to standby or sleep mode, the efficiency improvent is better than 13% which will have noticeable contribution in extending battery run time thus contributing to lowering the carbon footprint of human consumption.

Surface Electromyography (SEMG) systems are utilized throughout the medical industry to study abnormal electrical activity of the human muscle. Historically, SEMG systems employ surface (skin) mounted sensors that transmit electrical muscle data to a computer base via an umbilical cord. A typical SEMG analysis may exercise multiple sensors, each representing a unique data channel, positioned about the patient's body. Data transmission cables are linked between the surface mounted sensor nodes and a backpack worn by the patient. As the number of sensors increases, the patient's freedom of mobility decreases due to the lengthy data cables linked between the surface sensors and the backpack. An N-channel wireless SEMG system has been developed based on the ZigBee wireless standard. The system includes N-channels, each consisting of a wireless ZigBee transmitting modem, an 8-bit microcontroller, a low-pass filter and a pre-amplifier. All channels stream data to a central computer via a wireless receiving modem attached directly to the computer. The data is displayed to the user through graphical development software called LabView. The wireless surface electromyography(WSEMG) system successfully transmits reliable electrical muscle data fiom the patient to a computer base. The development of a WSEMG system offers an attractivealternative to implementing wired surface electromyography testing by facilitating thefreedom of patient mobility not bound by data transmission cables.