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abstract: This dissertation presents innovative techniques to develop performance-based models and complete transient models of induction motor drive systems with vector controls in electro-magnetic transient (EMT) and positive sequence transient stability (PSTS) simulation programs. The performance-based model is implemented by obtaining the characteristic transfer functions of perturbed active and reactive power consumptions with respect to frequency and voltage perturbations. This level of linearized performance-based model is suitable for the investigation of the damping of small-magnitude low-frequency oscillations. The complete transient model is proposed by decomposing the motor, converter and control models into d-q axes components and developing a compatible electrical interface to the positive-sequence network in the PSTS simulators. The complete transient drive model is primarily used to examine the system response subject to transient voltage depression considering increasing penetration of converter-driven motor loads. For developing the performance-based model, modulations are performed on the supply side of the full drive system to procure magnitude and phase responses of active and reactive powers with respect to the supply voltage and frequency for a range of discrete frequency points. The prediction error minimization (PEM) technique is utilized to generate the curve-fitted transfer functions and corresponding bode plots. For developing the complete drive model in the PSTS simulation program, a positive-sequence voltage source is defined properly as the interface of the model to the external system. The dc-link of the drive converter is implemented by employing the average model of the PWM converter, and is utilized to integrate the line-side rectifier and machine-side inverter. Numerical simulation is then conducted on sample test systems, synthesized with suitable characteristics to examine performance of the developed models. The simulation results reveal that with growing amount of drive loads being distributed in the system, the small-signal stability of the system is improved in terms of the desirable damping effects on the low-frequency system oscillations of voltage and frequency. The transient stability of the system is also enhanced with regard to the stable active power and reactive power controls of the loads, and the appropriate VAr support capability provided by the drive loads during a contingency. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2016

Στην παρούσα διπλωματική εργασία γίνεται περιγραφή του ηλεκτρικού κινητήριου συστήματος της Πατραϊκής Χαρτοποιίας αποτελούμενο από κινητήρες συνεχούς ρεύματος για την παραγωγή χαρτιού "tissue". Επίσης παρουσιάζεται η σχεδίαση συστήματος καταγραφής βλαβών σε περιστρεφόμενες μηχανές μέσω της ανάλυσης φάσματος κραδασμών στο πλαίσιο της εφαρμοσμένης μεθόδου παρακολούθησης κραδασμών της προβλεπτικής συντήρησης. / In the current diploma thesis takes place a description of the electric motor drive system of Patraikh Xartopoiia which consist of direct current machines for the production of tissue type paper. Furthermore the design of damage recording system in rotating motors through vibration analysis is presented in the line of vibration monitoring applied method.

The objective of this semester thesis is design of the control algorithm, needed control and power circuits and PCB design for the unfinished bicycle concept with a combustion engine and electric power transmission. The control algorithm had to be designed to make efficient use of the combustion engine performance and to minimalize the fuel consumption and noise level of the device. All circuits are fully implemented by analog components for which were designed printed circuit boards using program Eagle and this boards were revived and debugged.

A conceptual design and realization of a motor bike using combustion engine and electrical power transfer is the objective of this master´s thesis. Control strategy that allows combustion engine to reach maximal efficiency cooperating with wide range speed and torque operating area electromotor was created. All function blocks were realized. Also hardware of all needed parts was developed. The last part was a design and debugging of control software. Finally the functionality was documented by test drives and measurements.