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The master’s thesis is focused on the creation of models of DC/DC converters and control program for input parameters and their configuration. The first part is theoretical and she is dedicated to the description of the program Matlab. The second chapter is dedicated to DC/DC converters. Their function is described there and the necessary equations for the design are derived. All of this is complemented by the calculation of line losses in semiconductor elements and the design of voltage and current regulator. The last two parts deal with the description of the created models in Simulink and control program in a graphical environment. The created program is able to edit and recalculate parameters of the converters, calculate line losses on semiconductor components, perform a model simulation or open it.

Master’s thesis contains description parameters of microcontroller ATMEGA644P, also contains differences between older and newer version of microcontrollers ATMEGA644 and ATMEGA644PA. Inside structure of microcontroller, memories and peripherals are described here. The construction of the universal microcontroller unit is main target of this thesis. The unit contains supply, A/D converter, current loop, communication interfaces, temperature sensor, accelerometer and other. The unit collects and saves data, communicates by interfaces and manages other functions. Using devices and circuits are described in this thesis. Development of software for microcontroller(firmware) are positioned to last part of this thesis. This software control functions of all parts positioned on the unit.

Diploma thesis describes the design of an switched mode power supply with switching at zero voltage for driving the anode of Anode-layer type ion source. First aim of thesis is ion sources and specialy Anode-layer type of ion source in detail. Main aim of thesis are important aspects of the design of switching mode power supply, which comes later the detailed construction of an switched mode power supply with output voltage 2800 V at output power 2800 W.

Moving parts cause vibrations and tend to wear out. In applications where maintenance is complicated, solutions without moving parts are therefore advantageous. Electrohydrodynamic pumps are such a solution. Instead of mechanical propulsion, they use strong electric fields to induce movement in a dielectric cooling liquid. These pumps require very little power, but to generate sufficiently strong electric fields, they need to be fed with very high voltage.  This project explored various methods for designing DC/DC-converters which fulfil the demands of an electrohydrodynamic pump. This was done by altering and combining existing topologies that were deemed to be relevant. The main method for testing and evaluation was by simulating in LTspice. The project also briefly investigated methods of overcurrent protection. This was relevant because gas bubbles in the cooling fluid can cause electric arcs which damage the pumps. Three converter topologies were chosen for further evaluation. First, a conventional resonant Royer-based converter that has previously been used by APR Technologies which was altered by the inclusion of a feedback loop. Second, a high-frequency resonant Royer-based converter with a planar air-core transformer. Third, a transformerless converter with a switched boost converter IC. All circuits included a Cockroft-Walton voltage multiplier bridge. The two resonant Royer-based converters fulfilled all requirements except the one on efficiency, while the transformerless converter fulfilled all requirements except the one on cost, set by APR. The more expensive transformerless converter had a significantly higher efficiency and a wider range of acceptable input voltages. Furthermore three general conclusions were drawn. The first was that planar air-core transformers are not beneficial compared to conventional transformers in these type of applications. The second was that a discrete voltage regulator controlled by feedback from the output is more effective than using a voltage regulator without feedback, as it also eliminates temperature and load variations. The third conclusion was that to protect the circuits from overcurrent, a large series resistor is needed, which causes significantly lowered efficiency.

Electrical energy is used at approximately the rate of 15 Terawatts world-wide. Generating this much energy has become a primary concern for all nations. There are many ways of generating energy among which the most commonly used are non-renewable and will extinct much sooner than expected. Very active research is going on both to increase the use of renewable energy sources and to use the available energy with more efficiency. Among these sources, solar energy is being considered as the most abundant and has received high attention. The mobile phone has become one of the basic needs of modern life, with almost every human being having one.Individually a mobile phone consumes little power but collectively this becomes very large. This consideration motivated the research undertaken in this masters thesis. The objective of this thesis is to design a model for solar power based charging circuits for mobile phone using Simulink(R). This thesis explains a design procedure of solar power based mobile charger circuit using Simulink(R) which includes the models for the photo-voltaic array, maximum power point tracker, pulse width modulator, DC-DC converter and a battery. The first part of the thesis concentrates on electron level behavior of a solar cell, its structure and its electrical model.The second part is to design an array of solar cells to generate the desired output. Finally, the third part is to design a DC-DC converter which can stabilize and provide the required input to the battery with the help of the maximum power point tracker and pulse width modulation. The obtained DC-DC converter is adjustable to meet the requirements of the battery. This design is aimed at charging a lithium ion battery with nominal voltage of 3.7 V, which can be taken as baseline to charge different types of batteries with different nominal voltages.

L'objectif de la thèse est de concevoir des compensateurs discrets qui permettent de compenser les non-linéarités introduites par les différents éléments dans la boucle de commande numérique, tout en maintenant des performances dynamiques élevées, des temps de développement rapide, et une structure reconfigurable. Ces compensateurs discrets doivent également avoir des temps de réponse rapide, avoir une déviation de la tension minimale et avoir, pour un étage de puissance donné, un temps de récupération rapide de la tension. Ces performances peuvent être atteintes par des compensateurs discrets conçus sur la base de techniques de contrôle linéaires et non linéaires. Pour obtenir une réponse rapide et stable, la thèse propose deux solutions : La première consiste à utiliser des techniques de contrôle linéaires et de concevoir le compensateur discret tout en gardant la bande passante la plus élevée possible. Il est communément admis que plus la bande passante est élevée, plus la réponse transitoire est rapide. L‘obtention d’une bande passante élevée, en utilisant des techniques de contrôle linéaires, est parfois difficile. Toutes ces situations sont mises en évidence dans la thèse. La seconde consiste à combiner les techniques de contrôle linéaires avec les techniques de contrôles non linéaires tels que la logique floue ou les réseaux de neurones. Les résultats de simulations ont permis de vérifier que la combinaison des contrôleurs non-linéaires avec les linéaires ont un meilleur rendement dynamique que les contrôleurs linéaires lorsque le point de fonctionnement varie. Avec l'aide des deux méthodes décrites ci-dessus, la thèse étudie également la technique de l’annulation des pôles-zéros (PZC) qui annule la fonction de transfert du convertisseur. Quelques modifications des techniques classiques de contrôle sont également proposées à partir de contrôleurs numériques afin d’améliorer les performances dynamiques. La thèse met également en évidence les non-linéarités qui dégradent les performances, propose les solutions permettant d'obtenir les meilleures performances, et lève les mystères du contrôle numérique. Une interface graphique est également introduite et illustrée dans le cas de la conception d'un convertisseur abaisseur de tension synchrone. En résumé, cette thèse décrit principalement l'analyse, la conception, la simulation, l’optimisation la mise en œuvre et la rentabilité des contrôleurs numériques. Une attention particulière est portée à l'analyse et l'optimisation des performances dynamique à haute fréquence et pour de faibles puissances des convertisseurs DC-DC abaisseur de tension. Ces convertisseurs fonctionnent en mode de conduction continue (CCM) à une fréquence de commutation de 1 MHz et s’appuie sur des techniques de contrôle linéaires et non linéaires de façon séquentielle. / The objective of the thesis is to design the discrete compensators which counteract the nonlinearities introduced by various elements in the digital control loop while delivering high dynamic performance, fast time-to-market and scalability. Excellent line and fast load transient response, which is a measure of the system response speed, with minimal achievable voltage deviation and a fast voltage recovery time for a given power stage can be achieved through the discrete compensators designed on the basis of linear and nonlinear control techniques. To achieve a stable and fast response, the thesis proposes two ways. One way is to use linear control techniques to design the discrete compensator while keeping the bandwidth higher. It is well-known fact that the higher the bandwidth, the faster is the transient response. Achieving higher bandwidth through linear control techniques sometimes becomes tricky. All those situations are highlighted in the thesis. The other way is to hybridize the linear control techniques with the nonlinear control techniques such as fuzzy logic or neural network based control techniques. Simulation results verify that hybridization of nonlinear controllers with the linear ones have better dynamic performance over linear controllers under the change of operating points. Along with using the two methodologies described above, the thesis also investigates the pole-zero cancellation (PZC) technique in which the poles and zeros of the compensator are placed in such a way that they cancel the effect of the poles or zeros of the buck converter to boost the phase margin at the required bandwidth. Some modifications are also suggested to the classical control techniques based digital controllers to improve the dynamic performance. The thesis highlights the nonlinearities which degrade the performance, a cost-effective solution that achieves good performance and the mysteries of digital control system. A graphical user interface is introduced and demonstrated for use with the design of a synchronous-buck converter. In summary, this thesis mainly describes the analysis, design, simulation, optimization, implementation and cost effectiveness of digital controllers with particular focus on the analysis and the optimization of the dynamic performance for high-frequency low-power DC-DC buck converter working in continuous conduction mode (CCM) operating at a switching frequency of 1 MHz using linear and nonlinear control techniques in a very sequential and comprehensive way.

The main goal of this thesis is to develop practical digital controller architectures for multi-phase dc-dc converters utilized in low power (up to few hundred watts) and cost-sensitive applications. The proposed controllers are suitable for on-chip integration while being capable of providing advanced features, such as dynamic efficiency optimization, inductor current estimation, converter component identification, as well as combined dynamic current sharing and fast transient response. The first part of this thesis addresses challenges related to the practical implementation of digital controllers for low-power multi-phase dc-dc converters. As a possible solution, a multi-use high-frequency digital PWM controller IC that can regulate up to four switching converters (either interleaved or standalone) is presented. Due to its configurability, low current consumption (90.25 μA/MHz per phase), fault-tolerant work, and ability to operate at high switching frequencies (programmable, up to 10 MHz), the IC is suitable to control various dc-dc converters. The applications range from dc-dc converters used in miniature battery-powered electronic devices consuming a fraction of watt to multi-phase dedicated supplies for communication systems, consuming hundreds of watts. A controller for multi-phase converters with unequal current sharing is introduced and an efficiency optimization method based on logarithmic current sharing is proposed in the second part. By forcing converters to operate at their peak efficiencies and dynamically adjusting the number of active converter phases based on the output load current, a significant improvement in efficiency over the full range of operation is obtained (up to 25%). The stability and inductor current transition problems related to this mode of operation are also resolved. At last, two reconfigurable digital controller architectures with multi-parameter estimation are introduced. Both controllers eliminate the need for external analog current/temperature sensing circuits by accurately estimating phase inductor currents and identifying critical phase parameters such as equivalent resistances, inductances and output capacitance. A sensorless non-linear, average current-mode controller is introduced to provide fast transient response (under 5 μs), small voltage deviation and dynamic current sharing with multi-phase converters. To equalize the thermal stress of phase components, a conduction loss-based current sharing scheme is proposed and implemented.

Στην παρούσα διπλωματική εργασία προσομοιώθηκε, μέσω του προγράμματος Matlab και συγκεκριμένα μέσω της εργαλειοθήκης Simulink, ένα υβριδικό μικροδίκτυο το οποίο αποτελούνταν από μια φωτοβολταϊκή διάταξη των 85W, ένα συσσωρευτή ιόντων-λιθίου (Liion battery), δυο DC-DC μετατροπείς και ένα R-L φορτίο. Στην συνέχεια πραγματοποιήθηκαν 4 διαφορετικές τεχνικές ελέγχου σε 2 σημεία, έναν στην πλευρά του φωτοβολταϊκού και έναν στην πλευρά της μπαταρίας. Ο έλεγχος στην πλευρά του φωτοβολταϊκού στόχευε το ρεύμα του φωτοβολταϊκού κάθε χρονική στιγμή να έχει την κατάλληλη τιμή προκειμένου να επιτυγχάνεται η μέγιστη ισχύς μέσω σημείου απόδοσης της μέγιστης ισχύος (MPPT). Ο έλεγχος στην πλευρά της μπαταρίας έχει ως σκοπό την διατήρηση της τάσης του φορτίου στα 100 V.(Vload_reference=100V). Οι έλεγχοι που πραγματοποιήθηκαν ήταν με χρήση PI ελεγκτών, έλεγχοι εκμεταλλευόμενοι την παθητικότητα του Euler-Lagrange συστήματος (PBC), με χρήση ασαφών (fuzzy) ελεγκτών και με χρήση νευρο-ασαφών (neuro-fuzzy) ελεγκτών. / In this diploma thesis a DC hybrid microgrid was simulated by using the program Matlab and specifically the toolbox Simulink. The microgrid consists of a photovoltaic array, a Li-ion battery storage, two DC-DC converters and an R-L load. Four different control methods were then applied to our system in 2 places, one on the photovoltaic array and one on the battery. The one on the photovoltaic array aimed that the PV current would be such that every time the maximum power from the PV would be achieved through a maximum power point tracker. The one on the battery has the purpose of maintaining the load voltage at 100 Volts. The control methods which were implied were PI controllers, passivity based control, fuzzy controllers and neuro-fuzzy controllers.

Στόχος της παρούσας διπλωματικής εργασίας είναι ο σχεδιασμός και η κατασκευή του ηλεκτρικού κινητηρίου συστήματος ενός ηλεκτροκίνητου σκάφους. Πραγματοποιήθηκαν μία σειρά από τεχνικές επεμβάσεις ώστε να μετατραπεί ένα απλό σκάφος σε ηλεκτροκίνητο. Στην εποχή μας τα ηλεκτροκίνητα σκάφη και η ηλεκτρική πρόωση αποτελούν τμήμα των ηλεκτροκίνητων μέσων μεταφοράς. Τα ηλεκτροκίνητα μέσα μεταφοράς αποτελούν πιθανή λύση στην συνεχώς αυξανόμενη ζήτηση στον τομέα των μεταφορών καθώς και στα ενεργειακά και περιβαλλοντικά προβλήματα που αυτή προκαλεί. Ο υψηλός βαθμός απόδοσης των ηλεκτρικών κινητήρων και των ηλεκτρονικών μετατροπέων ισχύος, το υψηλό επίπεδο ελέγχου μέσω των ηλεκτρονικών μετατροπέων ισχύος που προσφέρει ευκινησία σε ένα σκάφος, η έλλειψη θορύβου-διαταραχών και η απουσία ρύπανσης μας οδηγούν στη χρήση των ηλεκτροκίνητων σκαφών και της ηλεκτρικής πρόωσης όλο και περισσότερο στις μέρες μας. Στη συγκεκριμένη εφαρμογή για πρακτικούς λόγους αλλά και για λόγους ασφάλειας οδηγηθήκαμε στην επιλογή κινητήρα συνεχούς ρεύματος (Σ.Ρ.) μονίμου μαγνήτη χαμηλής τάσης 24V. Αυτό έχει ως αποτέλεσμα υψηλή τιμή ρεύματος για την επίτευξη της απαιτούμενης ισχύος 1,5 kW . Για αυτό το λόγο σχεδιάστηκε και κατασκευάστηκε ο ηλεκτρονικός μετατροπέας υποβιβασμού συνεχούς τάσης σε συνεχή με διαδοχική αγωγή τεσσάρων κλάδων, ο οποίος έχει τη δυνατότητα διαχείρισης υψηλών τιμών ρεύματος και είναι ιδανικός για τέτοιου είδους εφαρμογές. Ο συγκεκριμένος μετατροπέας αποτελείται από 4 παράλληλους κλάδους, λειτουργεί στην συνεχή αγωγή και υποβιβάζει την τάση των 36V σε 0-24V για τον έλεγχο των στροφών του κινητήρα, ο οποίος έχει ονομαστικό ρεύμα 78A. Ο μετατροπέας εξετάστηκε αρχικά μέσω της εξομοίωσης χρησιμοποιώντας το λογισμικό PSpice και στη συνέχεια πειραματικά πραγματοποιώντας μία σειρά από δοκιμές και μετρήσεις. Από τις δοκιμές, παρατηρούμε ότι ο βαθμός απόδοσης του μετατροπέα διαδοχικής αγωγής που κατασκευάστηκε, κυμαίνεται γύρω στο 95%, άρα είναι μια καλή λύση στην οδήγηση κινητήρων συνεχούς ρεύματος (Σ.Ρ.) χαμηλής τάσης (υψηλού ρεύματος). Τέτοιοι κινητήρες χρησιμοποιούνται σε πληθώρα εφαρμογών ηλεκτροκίνητων μέσων μεταφοράς. Η καθέλκυση του ηλεκτροκίνητου σκάφους και οι δοκιμές που πραγματοποιήθηκαν στη θάλασσα, δίνουν σαφή εικόνα των πλεονεκτημάτων της ηλεκτρικής πρόωσης. / The object of this diploma thesis is the designing and the construction of an electric drive system for an electric boat. A number of technical interventions were made to transform a simple boat to an electrically driven boat. In our days the electric boats and the electric propulsion in general constitute a part of the electric transportation. The electric transportation may be a possible solution in the continuously increasing demand in the sector of transports as well as in energy and environmental problems that this causes. The high efficient electric machines and power electronic converters, the high control level of power electronics that offers manoeuvrability in a ship, the lack of noise - disturbance and the absence of pollution lead us to use electric boats and electric propulsion more and more in our days. In our application for practical and safety reasons we were led to the choice of a low voltage permanent magnet direct current (DC) motor. This is resulting to a high value of current to get the nominal power of 1.5 kW. For this reason an interleaved four – channel dc/dc converter was designed and constructed which has the ability to control high currents and is ideal for such type applications. The particular converter is constituted by 4 parallel channels, it is working in the continuous conduction mode (CCM) and it degrades the voltage of 36V to 0-24V for the control of the rpm of the dc propulsion motor which its full load current is 78A. Firstly a number of simulations made via PSpice program and also a number of experiments to see how the converter is working. The experiments shows that the efficiency of the interleaved converter of the application is about 95%, so it is a good solution for driving low voltage – high current dc motors. Such types of electric motors are used in many electric transportation applications. The launching of the boat and a number of sea tests shows us the advantages electric propulsion has.