Diante de discrepâncias na literatura sobre a recomendação de alguns modelos de propaganda de se emparelhar os apelos (racionais ou emocionais) à atitude do consumidor sobre o produto (predominantemente cognitiva ou predominantemente afetiva), o objetivo geral desta Tese foi avaliar tal recomendação. A revisão bibliográfica evidenciou algumas lacunas teóricas: 1) generalização indevida de resultados de estudos sobre formatos de propaganda para produtos de outras categorias; 2) não mensuração direta dos componentes cognitivo e afetivo da atitude do consumidor nos modelos de propaganda, que consideram apenas o tipo de necessidade que o produto satisfaz e o envolvimento do consumidor como determinante da atitude sobre o produto; 3) não consideração de outras características do consumidor, além do envolvimento, como determinante da atitude nos modelos de propaganda; 4) ausência da atitude do consumidor sobre o produto dentre os antecedentes da atitude do consumidor frente a anúncio. Procurando superar tais deficiências, foi empreendida pesquisa de campo contemplando: a) uma categoria de produto específica (medicamentos / medicamentos para emagrecer); b) a mensuração dos componentes cognitivo e afetivo da atitude; c) a avaliação de outras características do consumidor (estado de saúde / peso e experiência com o produto) que influenciam sua atitude; d) atitude do consumidor sobre o produto como possível antecedente da atitude dele frente a anúncio. A pesquisa empírica consistiu de três etapas. A primeira, sobre as particularidades da propaganda de medicamentos no Brasil, constatou maior uso de apelos emocionais. A segunda etapa, referente aos componentes cognitivo e afetivo da atitude do consumidor sobre medicamentos, encontrou predominância do componente cognitivo em pessoas saudáveis e de ambos os componentes em pessoas com problemas de saúde. A terceira etapa, acerca de atitude do consumidor sobre medicamentos para emagrecer e atitude e intenção comportamental do consumidor frente a anúncios racional e emocional, apontou predominância do componente cognitivo na atitude sobre o produto e atitude e intenção comportamental mais favoráveis frente a anúncio racional. Em vista do objetivo geral da Tese, do lado dos anunciantes, os resultados da pesquisa de campo não confirmaram a recomendação de emparelhar os apelos da propaganda à atitude do consumidor sobre o produto. Apelos emocionais são mais utilizados (primeira etapa da pesquisa), enquanto a atitude dos consumidores sobre esse tipo de produto é predominantemente cognitiva (segunda etapa da pesquisa). Os apelos utilizados na propaganda de medicamentos podem não estar sendo os mais adequados. Do lado dos consumidores, a recomendação de emparelhamento foi confirmada, pois a atitude dos consumidores sobre medicamentos para emagrecer é predominantemente cognitiva e eles tiveram atitude e intenção comportamental mais favoráveis frente ao anúncio racional. Os resultados trazem algumas implicações gerenciais. Do lado dos anunciantes, há insights para uma maior efetividade da propaganda e o alinhamento dela com as exigências legais. Parece ser mais adequado informar do que simplesmente tentar persuadir com apelos emocionais. Os benefícios funcionais do produto influenciam mais a formação da atitude sobre medicamentos. Sendo tais benefícios abordados na propaganda (apelos racionais), é provável que ela seja mais persuasiva. Do lado do governo, os resultados podem auxiliar às autoridades no seu objetivo de modernizar e atualizar o regulamento da propaganda de medicamentos, bem como na implementação de políticas de educação e conscientização da população sobre os perigos da auto-medicação. Pois sendo apelos racionais mais persuasivos, não significa que eles não possam gerar uso indevido de remédios ou auto-medicação. A tese termina expondo suas limitações e propondo lineamentos para pesquisas futuras. / There are discrepancies in the literature about the recommendation, of some advertising models, toward matching the appeals (rational or emotional) to the product consumer\'s attitude (predominantly cognitive or predominantly affective). In this context, the main objective of this Dissertation was to evaluate such recommendation. The literature review evidenced some theoretical gaps: 1) improper generalization of results from studies on advertising formats on one product category to other categories; 2) no direct measurement of the cognitive and affective components of the consumer\'s attitude in advertising models, that just consider the type of need that the product satisfies and the consumer\'s involvement as determinants of the product attitude; 3) no consideration of other consumer\'s characteristics, beyond the involvement, as determinants of attitude in advertising models; 4) absence of the consumer\'s product attitude among the antecedents of the consumer?s advertisement attitude. Trying to overcome such deficiencies, field research was undertaken regarding: a) a specific product category (medicines / medicines to lose weight); b) the measurement of the cognitive and affective components of attitude; c) the evaluation of other consumer\'s characteristics (health condition / weigh and experience with the product) that influence attitude; d) the consumer\'s product attitude as possible antecedent of attitude toward advertisement. The empiric research consisted of three stages. The first, about the particularities of medicines advertising in Brazil, confirmed larger use of emotional appeals. The second stage, regarding the cognitive and affective components of consumer\'s attitude toward medicines, found predominance of cognitive component in healthy people and of both components in people with health problems. The third stage, concerning the consumer\'s attitude toward medicines to lose weight and attitude and behavioral intention toward rational and emotional ads, pointed out predominance of cognitive component in attitude toward product, and attitude and behavioral intention more favorable toward rational ad. In light of the general objective of the Thesis, from the point of view of advertisers, the results of the field research didn\'t confirm the recommendation of matching the appeals of the advertising to the consumer\'s product attitude. Emotional appeals are more used (first stage of the research), while the consumers\' attitude on that product type is predominantly cognitive (second stage of the research). Perhaps the appeals used in medicines advertising aren?t the most appropriate. From the point of view of consumers, the matching recommendation was confirmed. While the consumers\' attitude toward medicines to lose weight is predominantly cognitive, they had attitude and behavioral intention more favorable toward rational ad. Results bring some managerial implications. To advertiser, there are insights for better effectiveness of advertising and alignment with legal restrictions. There seems to be more appropriate to inform than just try to persuade with emotional appeals. The functional benefits of the product influence more the attitude formation toward medicines. Being such benefits approached in advertising (rational appeals), it is probable grater persuasiveness. Results of this Dissertation can help authorities to modernize and to update the regulation of medicines advertising, as well as the implementation of an educational policy about the dangers of self-medication. Especially because the use of rational appeals doesn\'t mean that they cannot generate improper use of medicines or self-medication. The Dissertation ends with the limitations and directions for future researches.

Diante de discrepâncias na literatura sobre a recomendação de alguns modelos de propaganda de se emparelhar os apelos (racionais ou emocionais) à atitude do consumidor sobre o produto (predominantemente cognitiva ou predominantemente afetiva), o objetivo geral desta Tese foi avaliar tal recomendação. A revisão bibliográfica evidenciou algumas lacunas teóricas: 1) generalização indevida de resultados de estudos sobre formatos de propaganda para produtos de outras categorias; 2) não mensuração direta dos componentes cognitivo e afetivo da atitude do consumidor nos modelos de propaganda, que consideram apenas o tipo de necessidade que o produto satisfaz e o envolvimento do consumidor como determinante da atitude sobre o produto; 3) não consideração de outras características do consumidor, além do envolvimento, como determinante da atitude nos modelos de propaganda; 4) ausência da atitude do consumidor sobre o produto dentre os antecedentes da atitude do consumidor frente a anúncio. Procurando superar tais deficiências, foi empreendida pesquisa de campo contemplando: a) uma categoria de produto específica (medicamentos / medicamentos para emagrecer); b) a mensuração dos componentes cognitivo e afetivo da atitude; c) a avaliação de outras características do consumidor (estado de saúde / peso e experiência com o produto) que influenciam sua atitude; d) atitude do consumidor sobre o produto como possível antecedente da atitude dele frente a anúncio. A pesquisa empírica consistiu de três etapas. A primeira, sobre as particularidades da propaganda de medicamentos no Brasil, constatou maior uso de apelos emocionais. A segunda etapa, referente aos componentes cognitivo e afetivo da atitude do consumidor sobre medicamentos, encontrou predominância do componente cognitivo em pessoas saudáveis e de ambos os componentes em pessoas com problemas de saúde. A terceira etapa, acerca de atitude do consumidor sobre medicamentos para emagrecer e atitude e intenção comportamental do consumidor frente a anúncios racional e emocional, apontou predominância do componente cognitivo na atitude sobre o produto e atitude e intenção comportamental mais favoráveis frente a anúncio racional. Em vista do objetivo geral da Tese, do lado dos anunciantes, os resultados da pesquisa de campo não confirmaram a recomendação de emparelhar os apelos da propaganda à atitude do consumidor sobre o produto. Apelos emocionais são mais utilizados (primeira etapa da pesquisa), enquanto a atitude dos consumidores sobre esse tipo de produto é predominantemente cognitiva (segunda etapa da pesquisa). Os apelos utilizados na propaganda de medicamentos podem não estar sendo os mais adequados. Do lado dos consumidores, a recomendação de emparelhamento foi confirmada, pois a atitude dos consumidores sobre medicamentos para emagrecer é predominantemente cognitiva e eles tiveram atitude e intenção comportamental mais favoráveis frente ao anúncio racional. Os resultados trazem algumas implicações gerenciais. Do lado dos anunciantes, há insights para uma maior efetividade da propaganda e o alinhamento dela com as exigências legais. Parece ser mais adequado informar do que simplesmente tentar persuadir com apelos emocionais. Os benefícios funcionais do produto influenciam mais a formação da atitude sobre medicamentos. Sendo tais benefícios abordados na propaganda (apelos racionais), é provável que ela seja mais persuasiva. Do lado do governo, os resultados podem auxiliar às autoridades no seu objetivo de modernizar e atualizar o regulamento da propaganda de medicamentos, bem como na implementação de políticas de educação e conscientização da população sobre os perigos da auto-medicação. Pois sendo apelos racionais mais persuasivos, não significa que eles não possam gerar uso indevido de remédios ou auto-medicação. A tese termina expondo suas limitações e propondo lineamentos para pesquisas futuras. / There are discrepancies in the literature about the recommendation, of some advertising models, toward matching the appeals (rational or emotional) to the product consumer\'s attitude (predominantly cognitive or predominantly affective). In this context, the main objective of this Dissertation was to evaluate such recommendation. The literature review evidenced some theoretical gaps: 1) improper generalization of results from studies on advertising formats on one product category to other categories; 2) no direct measurement of the cognitive and affective components of the consumer\'s attitude in advertising models, that just consider the type of need that the product satisfies and the consumer\'s involvement as determinants of the product attitude; 3) no consideration of other consumer\'s characteristics, beyond the involvement, as determinants of attitude in advertising models; 4) absence of the consumer\'s product attitude among the antecedents of the consumer?s advertisement attitude. Trying to overcome such deficiencies, field research was undertaken regarding: a) a specific product category (medicines / medicines to lose weight); b) the measurement of the cognitive and affective components of attitude; c) the evaluation of other consumer\'s characteristics (health condition / weigh and experience with the product) that influence attitude; d) the consumer\'s product attitude as possible antecedent of attitude toward advertisement. The empiric research consisted of three stages. The first, about the particularities of medicines advertising in Brazil, confirmed larger use of emotional appeals. The second stage, regarding the cognitive and affective components of consumer\'s attitude toward medicines, found predominance of cognitive component in healthy people and of both components in people with health problems. The third stage, concerning the consumer\'s attitude toward medicines to lose weight and attitude and behavioral intention toward rational and emotional ads, pointed out predominance of cognitive component in attitude toward product, and attitude and behavioral intention more favorable toward rational ad. In light of the general objective of the Thesis, from the point of view of advertisers, the results of the field research didn\'t confirm the recommendation of matching the appeals of the advertising to the consumer\'s product attitude. Emotional appeals are more used (first stage of the research), while the consumers\' attitude on that product type is predominantly cognitive (second stage of the research). Perhaps the appeals used in medicines advertising aren?t the most appropriate. From the point of view of consumers, the matching recommendation was confirmed. While the consumers\' attitude toward medicines to lose weight is predominantly cognitive, they had attitude and behavioral intention more favorable toward rational ad. Results bring some managerial implications. To advertiser, there are insights for better effectiveness of advertising and alignment with legal restrictions. There seems to be more appropriate to inform than just try to persuade with emotional appeals. The functional benefits of the product influence more the attitude formation toward medicines. Being such benefits approached in advertising (rational appeals), it is probable grater persuasiveness. Results of this Dissertation can help authorities to modernize and to update the regulation of medicines advertising, as well as the implementation of an educational policy about the dangers of self-medication. Especially because the use of rational appeals doesn\'t mean that they cannot generate improper use of medicines or self-medication. The Dissertation ends with the limitations and directions for future researches.

The objective of the dissertation is to develop simplified analytical models for typical linear-motion and rotary-motion energy-conversion systems under active DC excitation without tedious numerical-simulation effort, and provide practical implementation of the models in optimal-design and thermal-protection aspects. The model of a vacuum automatic circuit recloser (a typical linear-motion system under DC excitation) is first developed in the form of a non-linear discontinuous eighth-order dynamic system. The model is then used to simulate the transient mechanical and electromagnetic performance during the opening and closing movements of the recloser. Such a model is not found in the literature. Although the model is based on certain simplifying assumptions, the result is validated by high-speed-camera measurements. In addition, the impact of key design variables is explored, based on which an improved recloser design is proposed, and helps to optimize capital and production costs without degrading performance. Further analytical investigation is carried out in modeling an inverter-fed induction motor (IM) (a typical rotary-motion system) with active DC injection. The IM is closed-loop controlled via two popular motor-control algorithms, namely, the direct-torque-control (DTC) algorithm and field-oriented-control (FOC) algorithm. Quantitative relationships between the changes of various machine variables during the active DC excitation are provided in the theoretical analysis. The developed DC-injection model is further simplified for practical implementation. The developed IM model under DC injection results in practical ways to excite a proper amount of DC current directly or indirectly into IM stator windings via different closed-loop motor-control algorithms. In a DTC motor-drive system, the modeling work makes it possible to excite the DC current indirectly inside the motor by superimposing a stator-flux-linkage-bias command in the flux-control loop or a torque-ripple command in the torque-control loop. The proposed flux-linkage-injection and torque-injection methods are the first novel efforts to implement the DC-signal-injection method in a DTC motor-drive system. In addition, the analysis carried out in a standard FOC drive system brings about an improved DC-current-injection approach: the torque ripple in this method is significantly mitigated compared to all existing DC-injection methods in FOC systems. The proposed DC-injection methods, either in a DTC or an FOC system, lead to a simple, low-cost, accurate, and non-invasive thermal-monitoring scheme for closed-loop-controlled IMs, where the stator temperature is indirectly estimated from stator resistance. Furthermore, considering inverter non-idealities, there is a challenge for a typical inverter drive to accurately estimate the DC component of motor terminal voltages. The existing methods are extended to provide a complete study of the real-time signal-processing technique for both DTC and FOC algorithms, and are finally implemented in a custom-built programmable motor-drive system. The experimental results demonstrate that the proposed technique gives accurate and robust stator-temperature estimation, regardless of the operating conditions and cooling modes. The analytical modeling method for the linear-motion and rotary-motion energy-conversion systems can be further extended to other power devices with similar mechanisms, and implemented in optimal design, control, and thermal-protection areas.

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.

Thesis advisor: John J. Michalczyk / The internet is changing health care right under out very noses. In doing so, it may have great impact on the physician-patient relationship. This relationship exists along a continuum, with paternalism at one end and total patient autonomy at the other. Various aspects of web-based health care (eHealth) are pushing the equilibrium one way or the other. Aspects of eHealth considered include: general health information websites, internet pharmacies, health communication infrastructures (as in physician-patient email and electronic medical records), and finally web-brokered organ transplantation. While there is obviously much to be aware of in terms of quality on the internet, it is concluded that an integration of eHealth into traditional medicine (thus creating cybermedicine) may not only help to mitigate the managed care crisis, but may also change the physician-patient relationship—hopefully for the better. / Thesis (BS) — Boston College, 2005. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program.

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.

This thesis is mainly devoted to the investigation of speed control methods for three phase cage induction motors with particular emphasis being given to Direct Torque Control (DTC) improved techniques.Classical Direct Torque Control has inherent disadvantages such as: problems during starting resulting from the null states, the compulsory requirement of torque and flux estimators, and torque ripple. In the classical DTC induction motor drive a voltage vector is applied for the entire period, and this causes the stator current and electromagnetic torque exceeds its reference value early during the cycle, causing a high torque ripple. Switching cycles then follows this, in which the zero switching vectors are applied in order to reduce the electromagnetic torque to reference value. This thesis suggests a technique based on applying to the inverter the selected active states just enough time to achieve the torque and flux references values. The rest of the switching period a null state is selected which won't almost change both the torque and the flux. Therefore, a duty ratio has to be determined each switching time. By means of varying the duty ratio between its extreme values (0 up to 1) it is possible to apply any voltage to the motor. The optimum duty ratio per sampling period is a non-linear function of the electromagnetic torque error, the stator flux position and the working point, which is determined by the motor speed and the electromagnetic torque. It is obvious that it is extremely difficult to model such an expression since it is a different non-linear function per working point. Therefore, this thesis is focused on performing a fuzzy-logic-based duty-ratio controller, where the optimum duty ratio is determined every switching period. Additionally, this Fuzzy Controller is adaptive and may be applied to any induction motor.A stator flux reference optimum controller is also designed, which not only helps to achieve a smaller torque ripple, but also reduces the reactive power consumption of the drive taken from the main supply. This is achieved by changing the stator flux reference value with reference being made to the correspondent torque reference value. Therefore, the stator flux reference value chosen is to be just of sufficient value to produce the desired torque Simulated results are shown in order to compare the classical DTC and the Fuzzy Logic based DTC.The control algorithms have been implemented on a PC/DSP based board that facilitates the use of parallelism in software design. A 1.5kW, three-phase induction motor drive has been designed and experimental data obtained from it in order to verify the results achieved by simulation.

Η θεματολογία της εργασίας αυτής περιλαμβάνει την υβριδική τεχνολογία στην αυτοκίνηση. Γίνεται μία εκτεταμένη ανάλυση των υβριδικών οχημάτων, αρχικά κάνοντας αναφορά στην ιστορία των υβριδικών και μη οχημάτων και έπειτα στα περιβαλλοντικά θεμάτα που τα έφεραν στο προσκήνιο. Η ανάλυση περιλαμβάνει επίσης την μελέτη των διαφόρων κατηγοριών υβριδικών οχημάτων, την εξέταση των κατασκευαστικών μερών τους και κλείνει με την παρουσίαση κάποιων χαρακτηριστικών οχημάτων που βγήκαν στην παραγωγή. Στη συνέχεια, η εργασία περνά στο πειραματικό της στάδιο, που περιλαμβάνει τη μελέτη και κατασκευή ενός ηλεκτροκινητήριου συστήματος για εφαρμογή σε πειραματικό όχημα. Το όχημα μετά τις επεμβάσεις θα είναι υβριδικό, κάνοντας χρήση δύο πηγών ενέργειας, ορυκτά καύσιμα και ηλεκτρισμό. Έγινε η προμήθεια του οχήματος και των απαραίτητων μερών του συστήματος δηλαδή ενός ασύγχρονου ηλεκτροκινητήρα και των μπαταριών, που είναι τύπου οξέος-μολύβδου. Ακολούθησαν μηχανολογικές μετατροπές στο αμάξωμα ώστε να δεχθεί το πρόσθετο σύστημα μετάδοσης κίνησης, οι οποίες και αναλύονται. Παράλληλα βρίσκονταν σε εξέλιξη οι μετατροπείς ισχύος που απαιτούνται στο σύστημα ηλεκτρικής κίνησης για να προσαρμόσουν τα ηλεκτρικά μεγέθη κατάλληλα ώστε να επιτρέψουν την ροή ισχύος από τις μπαταρίες προς τον κινητήρα, κατά την επιτάχυνση του οχήματος, και την επιστροφή ενέργειας στις μπαταρίες από τη μηχανή, που λειτουργεί ως γεννήτρια λαμβάνοντας ενέργεια από την κινητική του οχήματος. Οι απαιτούμενοι μετατροπείς είναι ένας αμφικατευθυντήριος μετατροπέας ανύψωσης – υποβιβασμού συνεχούς τάσης σε συνεχή και ένας μετατροπέας συνεχούς τάσης σε τριφασική εναλλασσόμενη, ή πιο απλά τριφασικός αντιστροφέας. Ο δεύτερος μετατροπέας πραγματοποιεί και τον έλεγχο της ροπής που παράγει σε κάθε στιγμή ο κινητήρας μέσω της μεθόδου του Άμεσου Έλεγχου Ροπής (DTC). Περιγράφονται οι μεθοδολογίες ελέγχου των τριφασικών ασύγχρονων κινητήρων και γίνεται λεπτομερής ανάλυση της χρησιμοποιούμενης μεθόδου. Στο τελευταίο τμήμα περιγράφονται οι πειραματικές μετρήσεις που διεξήχθησαν με το σύστημα που κατασκευάστηκε, στον εργαστηριακό πάγκο και επί του οχήματος της εφαρμογής. Τέλος, γίνεται ανάλυση των αποτελεσμάτων που προέκυψαν. / The subject of this work includes the use of hybrid technology in automotive. An extensive analysis of hybrid vehicles is carried out, referring to the history of hybrid and other vehicles and then to the environmental matters that brought hybrids to the fore. The analysis also includes the study of different types of hybrid vehicles, examining their components and ends with the presentation of some remarkable vehicles that have been produced. The work then passes into the experimental phase, involving the design and construction of an electric system to be applied in a conventional vehicle. The vehicle is meant to function as a hybrid, using two energy sources, fossil fuels and electricity. For the reason, a vehicle has been supplied along with the necessary parts of the system, which consist of an asynchronous electric motor and lead acid batteries. Mechanical modifications that were made to the chassis to accept the additional drivetrain are discussed in detail. The construction of the necessary power converters is carried out in parallel. Their purpose is to adjust the electrical values in order to allow the flow of power from the batteries to the engine during acceleration of the vehicle and return energy to the batteries from the electrical machine, which acts as generator powered from the vehicle’s wheels.. The required converters are: a bi-directional buck/boost DC to DC converter and a three-phase DC to AC converter, which is simply described as inverter. The second converter also performs the control of the torque produced at any time from the engine, using Direct Torque Control (DTC). Alternate methodologies are also described, while the used technique is fully analyzed. The final section describes the experimental procedures performed to the constructed systems. At first they are tested in the laboratory and afterwards they are applied on the vehicle. Finally, an analysis of the results is performed.

Thesis (MScEng)--Stellenbosch University, 2013. / Wind energy has proven to be a viable source of clean energy, and the worldwide demand is growing rapidly. Variable speed topologies, with synchronous generators and full-scale converters, are becoming more popular, and the e ective control of these systems is a current trend in wind energy research. The purpose of this study is the modelling, design, simulation and implementation of a small-scale, variable speed wind energy conversion system, incorporating the position sensorless direct torque control with space vector modulation, of a permanent magnet synchronous generator, including an RLC converter lter. Another aim is the development of a gain scheduling algorithm that facilitates the high level control of the system. Mathematical models of the combined lter-generator model, in the stationary and rotating reference frames, are presented and discussed, from which equivalent approximate transfer functions are derived for the design of the controller gains. The design of the controller gains, RLC lter components, gain scheduling concept and maximum power point tracking controller are presented. It is discovered that the RLC lter damping resistance has a signi cant e ect on the resonance frequency of the system. The system is simulated dynamically in both Simulink and the VHDL-AMS programming language. Additionally, the maximum power point tracking controller is simulated in the VHDL-AMS simulation, including a wind turbine simulator. The simulation results demonstrate good dynamic performance, as well as the variable speed operation of the system. The practical results of torque and speed controllers show satisfactory performance, and correlate well with simulated results. The detailed gain scheduling algorithm is presented and discussed. A nal test of the complete system yields satisfactory practical results, and con rms that the objectives of this thesis have been reached.

Variable-speed Induction motor drives are nowadays used for various kinds of industrial processes, transportation systems, wind turbines and household appliances in the world. The majority of drives are for general purpose speed control applications where accurate speed control is not required for entire speed range. But for high dynamic drive application, very precise and fast control of induction motor drive is essential. For such applications, sophisticated and well-performing control design is a key issue. Precise and accurate torque control of the Induction Motor (IM) can only be accomplished by vector control and direct torque control. In terms of space vector theory, vector control implies that the instantaneous torque is controlled by way of the stator current vector that is orthogonal to the rotor flux vector. Precise knowledge of the rotor flux angle is therefore essential for a vector controlled IM. IMs do not allow the flux position to be easily measured, so most modern vector controlled IM drives rely on flux estimation. This means that the flux angle is derived from a flux estimator, using the dynamic model of the IM. Given that the rotor speed of the IM is measured by a mechanical shaft sensor. Flux estimation is a fairly easy task. However, vector control of IM without mechanical shaft speed sensor is of current interest in industrial environment. The driving motivations behind the development in sensorless control are lower cost, improved reliability and operating environment. In this thesis, a sensorless vector control scheme for rotor flux estimation using current error space phasor based hysteresis controller is proposed including the method for estimation of leakage inductance, Ls. For frequencies of operation less than 25 Hz, the rotor voltage and hence the rotor flux position is computed during the inverter zero voltage space vector using steady state model of IM. For above 25 Hz, active vector period and steady state model of IM is used. The whole rotor flux estimation scheme is dependent on current error space phasor and the steady state motor model, with rotor flux as a reference vector. Since no terminal voltage sensing is involved, dead time effects will not create problem in rotor flux sensing at low frequencies of operation. But appropriate device on-state drop are compensated at low frequencies (below 5 Hz) of operation to achieve a steady state operation up to less than 1 Hz. A constant switching frequency hysteresis current controller is used in inner current control loop for the PWM regulation, with smooth transition of operation to six-step mode operation. A simple Ls estimation based on current error space phasor is also proposed to nullify the deteriorating effect on rotor flux estimation. The parameter sensitivity of the control scheme to changes in the stator resistance Rs is also investigated. The drive scheme is tested up to a low frequency operation less than 1 Hz. The extensive simulation and experiment results are presented to show the proposed scheme’s good dynamic performance extending up to six-step operation. In contrast to vector control, direct torque control (DTC) method requires the knowledge of stator resistance only and thereby decreasing the associated sensitivity to parameters variation and the elimination of speed information. DTC as compared to vector control does not require co-ordinate transformation and PI controller. DTC is easy to implement because it needs only two hysteresis comparators and a lookup table for both flux and torque control. This thesis also investigates the possibilities in improvement of direct torque control scheme for high performance induction motor drive applications. Here, two schemes are proposed based on the direct torque control scheme for IM drive using 12-sided polygonal voltage space vectors for fast torque control. The torque control scheme based on DTC algorithm is proposed using 12-sided polygonal voltage space vector. The basic DTC scheme is used to control the torque. But the IM drive is open-end type. For torque control, the voltage space vectors orthogonal to stator flux vector in 12-sided polygonal space vector structure are used as hexagonal space vector based DTC scheme. The advantages achieved due to 12-sided polygonal space vector are mainly fast torque control and small torque ripple. The fast transient of torque with precise control is achieved using voltage space vector placed with a resolution of ±15. The torque ripple will be less as 6n±1 (n=odd) harmonic torque is totally eliminated from the whole range of PWM modulation. The comparative analysis of proposed 12-sided polygonal voltage space vector based DTC and conventional hexagonal space vector based DTC is also presented. Extensive simulation and experiment results are also presented to show the fast torque control at speeds of operation ranging from 5 Hz to the rated speed. The concept of 12-sided polygonal space vector based DTC is further extended for a variable speed control scheme using estimated fundamental stator voltage for sector identification. The conventional DTC scheme uses stator flux vector for identification of the sector and the switching vector are selected based on this sector information to control stator flux and torque. However, the proposed DTC scheme selects switching vectors based on the sector information of the estimated fundamental stator voltage vector and its relative position with respect to the stator flux vector. The fundamental stator voltage estimation is based on the steady state model of IM and information of synchronous frequency which is derived from computed stator flux using a low pass filter technique. The proposed DTC scheme utilizes the exact position of fundamental stator voltage vector and stator flux vector position to select optimal switching vector for fast control of torque with small variation of stator flux within hysteresis band. The present DTC scheme allows the full load torque control with fast transient response to very low speeds of operation below 5 Hz. The extensive simulation and experiment results are presented to show the fast torque control for speed of operation from zero speed to rated speed. However, the present scheme will have all the advantages of DTC scheme using stator flux vector for sector identification. All the above propositions are first simulated by MATLAB/Simulink and subsequently verified by an experimental laboratory prototype. The proposed control schemes are experimentally verified on a 3.7 kW IM drive. The control algorithms of the sensorless vector control using current error space phasor as well as DTC using 12-sided polygonal voltage space vector are completely implemented on a TI TMS320LF2812 DSP controller platform. These are some of the constituents for chapters 2, 3 and 4 in this thesis. Additionally, the first chapter also covers a brief survey on some of the recent progresses made in the field of sensorless vector control, direct torque control and current hysteresis controller. The thesis concludes with suggestion for further exploration.