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Thesis (M.S.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 149-151)

Η παρούσα διπλωματική εργασία ασχολείται με την μέτρηση της κίνησης ενός αντικειμένου στους τρεις άξονες και ασύρματης μεταφοράς των δεδομένων αυτών σε ένα σταθμό βάσης. Η μέτρηση και μεταφορά γίνεται με χρήση δύο ενσωματομένων συστήματων, τα οποία είναι βασισμένα στην οικογένεια μικροελεγκτών STM32 της εταιρίας ST Microelectronics. Tα συγκεκριμένα σύστηματα εχουν το χαρακτηριστικό STM32-103STK και παρέχονται από την εταιρία Olimex. Αρχικά περιγράφονται τα χαρακτηριστικά και οι ιδιότητες του συγκεκριμένου συστήματος και στη συνέχεια παρουσιάζεται η μεθοδολογία πάνω στην οποία στηρίχθηκε η ανάπτυξη της ενσωματομένης εφαρμογής. Συγκεκριμένα, ο προγραμματισμός του συστήματος προϋποθέτει την συνεχή μέτρηση των τιμών της κίνησης στους τρεις άξονες και στη συνέχεια την ασύρματη αποστολή τους σε ένα δεύτερο σύστημα το οποίο είναι κατάλληλα προγραμματισμένο να δέχεται τα δεδομένα και στη συνέχεια αυτά να εγγράφονται στην οθόνη για να γίνουν ορατά από το χρήστη. / This diploma thesis is about measuring an object’s movement and then the wireless transfer of the measured data to a base station. The measurement and wireless transfer is performed via two embedded systems based on the STM32 microcontroller family by ST Microelectronics. The referenced system is the STM32-103STK provided by Olimex. At the beginning of the thesis there is a description of the main features and characteristics of the STM32 system and then the methodology used to develop the embedded application is presented. In more detail, the system is programmed to measure 3-axis acceleration and send the measured data wirelessly to a second system which then presents the data on an LCD screen.

Thesis (MTech (Electrical Engineering))--Cape Technikon, Cape Town, 2004 / This work describes research towards the development of a micro-controller based, standalone Internet telephone to be used as an alternative to conventional line telephones. Our definition of 'stand-alone' refers to the unit's capability to perform its function wholly without the need for an attached computer. The unit should be low cost and capable of allowing two users to communicate using the units. Bandwidth usage should be kept low to allow the unit to be used over dial up connections which are prevalent in South Africa. The units should be easy to use as the anticipated users may be unskilled. A module containing a 16-bit micro-controller, an Ethernet controller, flash memory and RAM was chosen as the controller. The module came with a real-time operating system and a TCPlIP stack. The session initiation protocol (SIP) was selected to perform the signalling. SIP uses the session description protocol (SDP) to negotiate the attributes of the media session to be established. The real-time transport protocol (RTP) was implemented to transport encoded audio between the end points. The RTP control protocol (RTCP) was implemented to provide basic quality of service parameters. The ITU-T recommendation G.729 annex A was the voice codec selected. Codec ICs were used to encode and decode the audio. The implementations were designed specifically for a two user, direct communication environment. That is two phone units were developed that communicated directly with each other and not through intermediary servers.

A solar thermal energy system is being rebuilt at University of KwaZulu-Natal School of Physics. A similar system is also being built in the University Eduardo Mondlane – Maputo Mozambique, in a team development work. The system is composed mainly of the following subsystems: (i) An Energy capture subsystem: paraboloidal dish concentrator with a heat receiver, mounted on a dual axis polar mount sun tracking assembly; (ii) An Energy storage subsystem: rock-bed thermal energy storage (TES) system; (iii) An Energy utilization subsystem: any user heat utilization (like a cooking or water boiling appliance); and (iv) A monitoring and control subsystem. The subsystem (iv) for performing a controlled charging of the Thermal Energy Storage from a hot plate simulated solar heat, was formerly developed and it was based on 2 conventional data loggers (HP/Agilent) and programs running on 2 PCs. The present work is aimed at performing the same plus additional monitoring and control tasks, based on a low cost microcontroller design. The monitoring and control subsystem based on the Atmel ATmega 32 MCU has been designed and built, capable of performing data acquisition, data logging and control of relevant system variables such as, hour and declination angles of the tracking concentrator; to cite some of the main variables. Besides a huge work of designing, building, programming and testing the microcontroller system itself, a special focus was given to the monitoring and control of the solar heat concentrator, to perform a dual axis sun tracking, so as to get as much as possible of the available solar radiation. Measurements of various system parameters such as, the sun tracking actual hour and declination angles, the inlet and outlet temperatures of both the heat receiver and the rock bed heat storage, etc., for the system under consideration have been carried out. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.

The thesis describes an optimal selective harmonic elimination strategy suitable for singlephase AC-DC converter-fed traction drives. The objective is to eliminate low-order supply current harmonics, including those injected into the supply due to load-side current ripple. Other advantages that the switching strategy has to offer over phase-control include improved supply power factor, reduced VA consumption for a given demand speed and load, reduced torque and speed ripple and smaller armature circuit smoothing inductance. The effect of field current boost on the dynamic response of the drive is also described. It is shown that field boost helps to reduce the speed rise-time by increasing the electromagnetic torque available during acceleration periods. Closed-loop control of a 4-quadrant DC drive is described and a comparison made between the performance of PID-control and pseudo-derivative feedback control. It is shown that pseudo-derivative feedback control has several advantages to offer, amongst which are ease of tuning of the controller gains and a superior performance following load torque disturbances. A laboratory size drive system was designed and built, and used to validate simulation predictions for both the switching strategy and pseudo-derivative feedback control. A microcontroller based hardware implementation of both the switching strategy and a digital pseudo-derivative feedback controller was adopted, with the switching strategy being implemented using an off-line approach of precalculating the switching angles and storing these in look-up tables. The armature voltage controller comprises a dual-converter employing IGBTs as switching devices. The use of IGBTs allows higher switching frequencies at significant power levels than would be possible if GTOs were used. It also simplifies the gate drive circuit design and minimises the need to use snubber circuits.

Thesis (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references (ℓ. 164-173)

Dissertation (Ph.D.)--Auburn University, / Abstract. Vita. Includes bibliographic references (p.109-113).

Thesis (M.S.)--University of Akron, Dept. of Electrical and Computer Engineering, 2006. / "December, 2006." Title from electronic thesis title page (viewed 12/31/2008) Advisor, Shivakumar Sastry; Committee members, Nathan Ida, James E. Grover; Department Chair, Alex De Abreu Garcia; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Στόχος της παρούσας διπλωματικής εργασίας, η οποία εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών, είναι η μελέτη και κατασκευή διάταξης για την παλμοδότηση και τον έλεγχο ενός κινητήρα τύπου ultrasonic, χρησιμοποιώντας ψηφιακό μικροελεγκτή ή FPGA. Αρχικά γίνεται μια παρουσίαση των χαρακτηριστικών των πιεζοηλεκτρικών κινητήρων, γίνεται αναφορά στην αρχή λειτουργίας τους και στα ισοδύναμα κυκλώματα που χρησιμοποιούνται για την ανάλυση της λειτουργίας τους. Στη συνέχεια παρουσιάζονται οι ηλεκτρονικοί μετατροπείς ισχύος που χρησιμοποιούνται για τον έλεγχο των κινητήρων αυτού του τύπου και γίνεται θεωρητική ανάλυση του τρόπου λειτουργίας τους και των μεθόδων παλμοδότησής τους και προσομοιώνεται ένας μονοφασικός αντιστροφέας παλμοδοτούμενος με τη μέθοδο ημιτονοειδούς διαμόρφωσης εύρους παλμών. Ακολουθεί μία περιγραφή των χαρακτηριστικών του μικροελεγκτή που χρησιμοποιήθηκε και του κώδικα του προγράμματός του. Στο επόμενο βήμα πραγματοποιείται η μελέτη και η κατασκευή ενός μετατροπέα συντονισμού για τον έλεγχο του κινητήρα, λόγω περιορισμών που τέθηκαν από το κύκλωμα παλμοδότησης και τέλος παρατίθενται παλμογραφήματα και μετρήσεις που προέκυψαν από τα πειράματα που διενεργήθηκαν. / The goal of this diploma thesis is the study and the construction of a converter in order to drive and control an ultrasonic motor, using digital microcontroller or FPGA.