No description available.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 37-39). Also available on the World Wide Web.

Research Project (M.B.A.) - Simon Fraser University, 2006. / MBA-MOT Program. Theses (Faculty of Business Administration) / Simon Fraser University. Senior supervisor: Dr. Elicia Maine.

This thesis describes the implementation of a novel microprocessor-controlled, 4-quadrant DC-to-DC converter for driving a DC servo motor. The converter is supplied from a fixed 28V DC voltage source and the output voltage can be varied throughout the range ±180V.

No description available.

No description available.

Η παρούσα διπλωματική εργασία αποτελεί μία μελέτη στον ψηφιακό έλεγχο ενός AC – Κινητήρα ειδικού τύπου. Ο τύπος αυτός είναι μία ασύγχρονη – επαγωγική μηχανή ενώ ο έλεγχος που πραγματοποιείται αποτελεί μέρος μίας ευρύτερης μορφής ελέγχου αυτή του FOC (Προσανατολισμένος προς κάποιο πεδίο έλεγχος). Ο χαρακτηρισμός του ως ψηφιακού οφείλεται στη χρήση του ελεγκτή TMDSHVMTRPFCKIT ο οποίος καθιστά εφικτή την οποιαδήποτε μορφή ελέγχου. Αξίζει να αναφερθεί πως ο έλεγχος δεν κάνει χρήση αισθητήρων ενώ τα προς έλεγχο μεγέθη δεν μετριούνται αλλά εκτιμώνται. Τέλος η όλη διαδικασία ελέγχου δύναται να παρακολουθείται κατά τη διάρκεια λειτουργίας του επαγωγικού κινητήρα κάνοντας χρήση του γραφικού λογισμικού GUI, το οποίο απαιτεί και την κατάλληλη επικοινωνία του ελεγκτή με τον προσωπικό Η/Υ. / This thesis is a study in digital control of a special type of AC - Motor. This type is an asynchronous - induction machine while the control made a part of a broader form control of FOC (Field Oriented toward some control). The characterization as digital due to using the TMDSHVMTRPFCKIT controller which makes possible any form of control. It is worth mentioning that the control does not use sensors to control while sizes are not measured but estimated. Finally the whole process control can be monitored during the operation of the induction motor using graphic software GUI, which requires the proper communication controller with the P/C.

The availability of high speed and high power switching devices, such as the IGBT, has opened the opportunity for an increasing number of grid-connected inverter applications that have historically been unachievable. Recently, the number of inverter applications has surged, with now the focus being on increasing the relative performance and power capability. Such applications include UPSs, dynamic voltage restorers, STATCOMs, frequency converters and distributed grid sources such as solar panels. The inverter switching frequency limits its associated bandwidth and hence performance. Every application can benefit by reduction of the extent of this limitation. While state of the art devices like IGBTs enable such applications, the onus is now on developing high bandwidth digital controllers; the ability to connect multiple devices together to achieve power scaling; and having the confidence that the applications will work with other systems on a grid.% Solutions for for improving the inverter performance, ability to scale the power and operation compliance with other grid-connected devices are sought. Constraints and limitations imposed by the hardware and traditional continuous-time derived controllers are identified. A discrete-time direct design controller is then developed specifically for digital controllers, that for the same inverter configuration, achieves twice the bandwidth of a well-tuned traditional controller. An important feature of a controller is having the configurability of being able to choose inverter bandwidth over stability margin. To provide power scaling above that of a single switching module, investigations are performed on the suitability of actively paralleling inverter modules. Both the use of the developed discrete direct design controller and the identification of potential inter-module instabilities for a particular configuration enables the application of paralleled inverters. The operation is confirmed through the application of a sixteen paralleled module inverter system. Finally, a graphical analysis technique is introduced for analysing complex grids that may include inverter systems. The graphical technique demonstrates stability constraints with a range of sources and loads, including both inverters and rotating machines, which historical analysis techniques have been unable to do.

Este trabalho propõe a adoção de uma estrutura de controle, com base na tese de doutorado de (BUEHNER, 2010), a qual utiliza um modelo com a dinâmica inversa da planta a ser controlada, de maneira a prover a pré-alimentação da tensão de referência para o controle de um conversor de potência monofásico, modulado por largura de pulso (PWM), obtendo-se bons resultados para o rastreamento da corrente do indutor de filtro conectado à saída deste conversor de potência. No trabalho, são apresentadas outras duas estruturas de controle por pré-alimentação, responsáveis respectivamente pelo cancelamento da perturbação gerada pela tensão na saída do filtro indutivo e pelo cancelamento do erro de tensão gerado pelo tempo morto. Com o intuito de assegurar o desempenho de rastreamento da corrente, face às variações de parâmetros do processo e as imperfeições existentes no modelamento da planta real, emprega-se a estrutura de controle proporcional, em malha fechada, assegurando a robustez da estrutura de controle, facilitando-se o ajuste da malha de controle. Os resultados de simulação e obtidos experimentalmente são comparados, validando-se efetivamente a estratégia de controle proposta. / This work presents the control structure based on (BUEHNER, 2010) PhD thesis, which uses an inverse dynamic model for the plant to be controlled, providing the feedforward voltage reference to control a single-phase, pulse width modulated power converter (VSI-PWM), achieving good results for the output inductor current tracking, connected on the power converter output. Two feedforward control structures are presented, for the cancellation of the voltage disturbance generated by the output filter voltage and the cancellation of voltage error generated by the dead time implementation, respectively. In order to ensure the current tracking performance in face of process parameter variations and modeling imperfections existing in the real plant, the closed loop proportional is employed under the proposed control structure, ensuring the control robustness, and facilitating the loop gain adjustments. The simulation and experimental results are obtained and compared, effectively evaluating the proposed control strategy.

O número crescente de cargas baseadas em conversores eletrônicos criou a preocupação com a distorção harmônica em sistemas de energia elétrica. Qualidade de energia é um assunto importante tanto para as companhias distribuidoras e geradoras de energia elétrica como para os consumidores. A utilização de equipamentos para a eliminação de harmônicos tornou-se necessária e são diversas as soluções possíveis. Em sistemas trifásicos com quatro fios, os filtros ativos de potência e os sistemas de energia ininterrupta são equipamentos empregados para a melhoria da qualidade de energia elétrica. Tais equipamentos apresentam em sua estrutura um conversor trifásico com quatro fios podendo ser do tipo fonte de tensão ou fonte de corrente. Este estudo propõe uma estratégia para a minimização da ondulação das correntes de linha e de neutro em um conversor do tipo fonte de tensão trifásico com quatro fios. A estratégia consiste em injetar uma tensão de seqüência zero nas referências dos blocos PWM\'s que não altere o valor médio da corrente, mas somente a sua ondulação. Propõe-se uma metodologia que possibilita a escolha de um valor ótimo para a tensão de seqüência zero. São também apresentados a região dos vetores sintetizáveis, a análise da tensão de saída e o modelamento do conversor. Propõe-se uma estratégia de controle de corrente com reguladores PI para um sistema trifásico com quatro fios usando conversor com quatro fios. O comportamento do conversor é verificado por simulações numéricas e resultados experimentais, confirmando o desempenho da estratégia de PWM proposta. / The growing number of power electronics-based loads has created concern about harmonic distortion in electric systems. Power quality is an important issue both for utilities and consumers. The use of harmonic filtering equipment has become necessary and many solutions have been studied. In three phase systems, active power filters and uninterruptible power supply are used for improving power quality. These equipments present in their topologies a three-phase four-wire voltage source converter or three-phase four-wire current source converter. This study proposes a strategy for the minimization of the line and neutral ripple current of a three-phase four-wire Voltage Source Converter. The strategy consists of injecting an instantaneous zero sequence to the references of a triangular carrier PWM that does not affects the local average of the converter output voltages, but only the ripple currents. A methodology to evaluate the instantaneous optimal value of the injected zero sequence voltage is presented. The locus of the synthesizable voltage vectors and the modeling of the converter are also shown. It presents a strategy of current control for three-phase four-wire systems using three-phase four-wire converter. The behavior of the converter is verified by numerical simulation and experimental results, confirming the performance of the proposed PWM strategy.