L'adénosine monophosphate cyclique (AMPc) est une molécule très largement conservée dans le monde du vivant. Chez les bactéries, cette molécule signal est impliquée, entre autres, dans l'adaptation aux changements de milieu, au développement de la virulence, à la sporulation et la compétence. Bien qu'il fut démontré dans les années 1970 que cette molécule nécessitait un transporteur afin de traverser la membrane cellulaire, l'identité de celui-ci restait jusqu'à très récemment inconnue. Ce n'est qu'en 2011 que Hantke et ses collègues démontrèrent l'implication de la protéine TolC dans l'export de l'AMPc. Au cours de ma thèse, j'ai démontré le rôle prépondérant du complexe Opp dans l'import d'AMPc chez Escherichia coli. Ce complexe, formé des protéines OppABCD et F, est connu pour transporter des oligopeptides et se trouve dans la membrane interne de nombreuses bactéries. Pour arriver à la conclusion de son implication dans le transport d'AMPc, une banque de mutants a été créée dans une souche ne produisant pas d'AMPc (cyaA-). Afin d'identifier le transporteur responsable de l'import de l'AMPc, différents cribles qui testent la présence de cette molécule dans la cellule, ont ensuite été réalisée sur ces clones. Après analyse des résultats obtenus, l'opéron opp a été pressenti comme étant nécessaire à l'entrée de l'AMPc dans la cellule. Le double mutant cyaA-oppA- a été créé et de nouvelles expériences sont venues confirmer notre hypothèse. La protéine OppA a ensuite était surexprimée et purifiée pour nous permettre de faire des tests biochimiques d'interaction entre AMPc et OppA, basés sur la fluorescence émise par la protéine elle-même ou un homologue de l'AMPc, l'ε-AMPc. Ces expériences nous ont permis de confirmer l'interaction entre la protéine OppA et l'AMPc. Le système Opp est donc le principal importateur d'AMPc chez Escherichia coli, mais il ne semble pas être l'unique transporteur impliqué. Un autre candidat très intéressant est le complexe Dpp, connu pour transporter les dipeptides. En effet, les expériences préliminaires effectuées démontrent une diminution de la concentration intracellulaire d'AMPc dans une cellule cyaA-dppA- comparée à celle observée dans une souche cyaA-. Les travaux réalisés pendant ces trois dernières années permettent de conclure que le complexe Opp est le principal importateur d'AMPc, très probablement secondé par le complexe Dpp. / Cyclic adenosine monophosphate (cAMP) is a signalling molecule conserved in all reigns of life. In bacteria, cAMP plays an important role in processes as diverse as the adaptation to a changing environment, the control of virulence, sporulation and competence. Although it has been proven in the 1970s that this molecule needs an active transporter to traverse the plasma membrane, the first one of these transporters was discovered only a few years ago. In 2011, Hantke et al have shown that the TolC protein is involved in the efflux of cAMP. During my PhD work I have identified the Opp complex as a major player of cAMP import into Escherichia coli. This complex, composed of proteins called OppABCD and F, is known to transport oligopeptides across the inner membrane of numerous bacterial species. To prove the involvement of the Opp complex in cAMP transport, I have used transposon mutagenesis to generate a collection of random mutants in a strain that does not produce cAMP (cyaA-). Different screens were used to detect mutants with impaired transport of extracellular cAMP into the cell. The opp operon emerged as the most promising candidate from this screen. The double mutant cyaA-oppA- was constructed and experiments designed to test the function of OppA confirmed our hypothesis. Subsequently, I overexpressed and purified OppA in order to perform biochemical experiments destined to measure the physical interaction between cAMP and OppA. I show that the Opp system is the major importer of cAMP in Escherichia coli. However, it seems that Opp is not the unique importer of cAMP. The other, very interesting candidate is the complex Dpp, known to transport dipeptides. Preliminary experiments revealed a decreased amount of cAMP in strain cyaA-dppA- compared to strain cyaA-. The experiments carried out during the last three years allow us to conclude that the Opp complex is the major importer of cAMP into E. coli and that the Dpp complex is probably a secondary transporter.

O sistema de transporte de oligopeptídios (sistema Opp) está envolvido em diferentes aspectos da fisiologia bacteriana, incluindo nutrição, comunicação intercelular e fatores associados com a virulência. Estes transportadores ABC são formados por uma proteína de ligação a oligopeptídios, uma permease e um domínio de ligação ao ATP. As Aeromonas são bactérias Gram-negativas aquáticas ubíquas associadas com várias doenças em humanos, especialmente, gastrenterites. Atualmente, A. hydrophila, A. sobria e A. caviae são consideradas como patogenos emergentes pela OMS. Neste contexto, o objetivo do presente trabalho foi caracterizar o sistema de transporte de oligopeptídios em Aeromonas utilizando para tanto diversas ferramentas bioinformáticas e moleculares. Os resultados mostraram que, assim como em outras bactérias Gram-negativas, os genes opp de Aeromonas encontram-se organizados em um único operon policistrônico formado por cinco genes (oppA, oppB, oppC, oppD e oppF). O gene oppA e a proteína periplásmica de ligação a oligopeptídios correspondente (OppA) são altamente conservados, mesmo entre bactérias de famílias distintas. O modelo da proteína OppA de A. hydrophila mostrou a estrutura típica Venus flytrap , semelhante ao modelo de S. typhimurium. Além disso, a presença do gene oppA foi confirmada em todas as linhagens avaliadas. A OppA de várias espécies de Aeromonas foram reconhecidas por anticorpos obtidos contra a OppA de E. coli, confirmando a similaridade entre estas proteínas, e a expressão da OppA em Aeromonas. O seqüenciamento completo ou parcial do gene oppA de diferentes espécies de Aeromonas permitiu confirmar a elevada conservação do mesmo, e corroborar dados filogenéticos prévios. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-22T17:08:12Z No. of bitstreams: 1 Dissertacao Fernanda Cattani.pdf: 1029794 bytes, checksum: cca1fad2170203cf94cc3056e3a6381b (MD5) / Made available in DSpace on 2014-05-22T17:08:12Z (GMT). No. of bitstreams: 1 Dissertacao Fernanda Cattani.pdf: 1029794 bytes, checksum: cca1fad2170203cf94cc3056e3a6381b (MD5) / The oligopeptide transport system (Opp system) is involved in different aspects of bacterial physiology, including nutrition, intercellular communication, and factors associated with virulence. These ABC transporters are formed by an oligopeptide binding protein, a permease, and ATP-binding domain. Aeromonas are ubiquous aquatic Gram-negative bacteria associated with several human diseases, particularly gastrointestinal disorders. Now a day, A. hydrophila, A. sobria and A. caviae are considered as emerging pathogens by the WHO. In this context, the objective of the present study was to characterize the oligopeptide transport system of Aeromonas using several bioinformatic and molecular tools. The results showed that as in other Gram-negative bacteria, the opp genes of Aeromonas are organized in a single policistronic operon formed by five genes (oppA, oppB, oppC, oppD and oppF). The oppA gene and its corresponding periplasmic oligopeptide-binding protein (OppA) are highly conserved, even between different bacterial families. A. hydrophila OppA model exhibits a typical Venus flytrap structure, similar to the S. typhimurium model. Furthermore, the presence of the oppA gene was confirmed in all the Aeromonas strains evaluated. The OppA of several Aeromonas species were recognized by antibodies obtained against E. coli OppA, confirming the similarity between these proteins, and the expression of the oligopeptide binding protein in Aeromonas. The complete or partial sequencing of the gene oppA of different species of Aeromonas allowed confirming the high conservation of this gene, and corroborate previous phylogenetic data.

O sistema de transporte de oligopeptídios (sistema Opp) está envolvido em diferentes aspectos da fisiologia bacteriana, incluindo nutrição, comunicação intercelular e fatores associados com a virulência. Estes transportadores ABC são formados por uma proteína de ligação a oligopeptídios, uma permease e um domínio de ligação ao ATP. As Aeromonas são bactérias Gram-negativas aquáticas ubíquas associadas com várias doenças em humanos, especialmente, gastrenterites. Atualmente, A. hydrophila, A. sobria e A. caviae são consideradas como patogenos emergentes pela OMS. Neste contexto, o objetivo do presente trabalho foi caracterizar o sistema de transporte de oligopeptídios em Aeromonas utilizando para tanto diversas ferramentas bioinformáticas e moleculares. Os resultados mostraram que, assim como em outras bactérias Gram-negativas, os genes opp de Aeromonas encontram-se organizados em um único operon policistrônico formado por cinco genes (oppA, oppB, oppC, oppD e oppF). O gene oppA e a proteína periplásmica de ligação a oligopeptídios correspondente (OppA) são altamente conservados, mesmo entre bactérias de famílias distintas. O modelo da proteína OppA de A. hydrophila mostrou a estrutura típica Venus flytrap , semelhante ao modelo de S. typhimurium. Além disso, a presença do gene oppA foi confirmada em todas as linhagens avaliadas. A OppA de várias espécies de Aeromonas foram reconhecidas por anticorpos obtidos contra a OppA de E. coli, confirmando a similaridade entre estas proteínas, e a expressão da OppA em Aeromonas. O seqüenciamento completo ou parcial do gene oppA de diferentes espécies de Aeromonas permitiu confirmar a elevada conservação do mesmo, e corroborar dados filogenéticos prévios. / The oligopeptide transport system (Opp system) is involved in different aspects of bacterial physiology, including nutrition, intercellular communication, and factors associated with virulence. These ABC transporters are formed by an oligopeptide binding protein, a permease, and ATP-binding domain. Aeromonas are ubiquous aquatic Gram-negative bacteria associated with several human diseases, particularly gastrointestinal disorders. Now a day, A. hydrophila, A. sobria and A. caviae are considered as emerging pathogens by the WHO. In this context, the objective of the present study was to characterize the oligopeptide transport system of Aeromonas using several bioinformatic and molecular tools. The results showed that as in other Gram-negative bacteria, the opp genes of Aeromonas are organized in a single policistronic operon formed by five genes (oppA, oppB, oppC, oppD and oppF). The oppA gene and its corresponding periplasmic oligopeptide-binding protein (OppA) are highly conserved, even between different bacterial families. A. hydrophila OppA model exhibits a typical Venus flytrap structure, similar to the S. typhimurium model. Furthermore, the presence of the oppA gene was confirmed in all the Aeromonas strains evaluated. The OppA of several Aeromonas species were recognized by antibodies obtained against E. coli OppA, confirming the similarity between these proteins, and the expression of the oligopeptide binding protein in Aeromonas. The complete or partial sequencing of the gene oppA of different species of Aeromonas allowed confirming the high conservation of this gene, and corroborate previous phylogenetic data.

O sistema de captação de oligopeptideos (Opp), responsável pela captação de peptídeos com 3 ou mais resíduos de aminoácidos, representa um mecanismo importante de obtenção de nutrientes em bactérias. O operon Opp é constituído por 5 genes, sendo OppD e F responsáveis pela codificação dos componentes geradores, OppB e C codificantes para as proteínas que delimitam o poro da membrana e OppA que codifica o componente ligante. Neste trabalho identificamos uma alta identidade entre as proteínas OppA expressas por diferentes cepas de E. coli, 4 espécies do gênero Shigella ( 99 %) e diferentes sorovares de Salmonella enterica (85%) mas registramos a ocorrência de vários sítios polimórficos inter-específicos. A presença do gene OppA foi confirmada em 58 cepas diarreiogênicas de E. coli, Shigella e Salmonella. A partir da proteína OppA recombinante foi obtido soro policlonal específico que revelou a presença da proteína em todas as linhagens estudadas. Desta forma, concluímos que a proteína OppA está presente e conversada em espécies e linhagens dos três gêneros de Enterobacteriaceae estudados. / The oligopeptide uptake system (Opp), involved with the uptake of peptides formed by 3 or more amino acid residues, represent important nutrient uptake mechanism. The Opp operon is usually represented by 5 structural genes, including OppD and OppF encoding proteins involved generation of energy , OppB and OppC, encoding membrane proteins delimiting a pore and OppA encoding the protein responsible both for specificity and affinity of the transport system toward different peptide substrates. In this study, we demonstrated that the OppA proteins expressed by different E. coli strains,4 Shigella species (99%) and different serovars of Salmonella enterica (85%) were quite conserved but the occurrence of inter-species polymorphism was demonstrated. The OppA gene was detected in 58 diarrheogenic E. coli, Shigella and Salmonella strains. Using a recombinant OppA protein produced in E. coli, specific polyclonal sera were generated and successfully applied in the immunological detection of the proteins expressed by the tested strains. Thus, we conclude that the OppA protein is present and conserved among species and strains of the three test Enterobacteriaceae genera.

O sistema de captação de oligopeptideos (Opp), responsável pela captação de peptídeos com 3 ou mais resíduos de aminoácidos, representa um mecanismo importante de obtenção de nutrientes em bactérias. O operon Opp é constituído por 5 genes, sendo OppD e F responsáveis pela codificação dos componentes geradores, OppB e C codificantes para as proteínas que delimitam o poro da membrana e OppA que codifica o componente ligante. Neste trabalho identificamos uma alta identidade entre as proteínas OppA expressas por diferentes cepas de E. coli, 4 espécies do gênero Shigella ( 99 %) e diferentes sorovares de Salmonella enterica (85%) mas registramos a ocorrência de vários sítios polimórficos inter-específicos. A presença do gene OppA foi confirmada em 58 cepas diarreiogênicas de E. coli, Shigella e Salmonella. A partir da proteína OppA recombinante foi obtido soro policlonal específico que revelou a presença da proteína em todas as linhagens estudadas. Desta forma, concluímos que a proteína OppA está presente e conversada em espécies e linhagens dos três gêneros de Enterobacteriaceae estudados. / The oligopeptide uptake system (Opp), involved with the uptake of peptides formed by 3 or more amino acid residues, represent important nutrient uptake mechanism. The Opp operon is usually represented by 5 structural genes, including OppD and OppF encoding proteins involved generation of energy , OppB and OppC, encoding membrane proteins delimiting a pore and OppA encoding the protein responsible both for specificity and affinity of the transport system toward different peptide substrates. In this study, we demonstrated that the OppA proteins expressed by different E. coli strains,4 Shigella species (99%) and different serovars of Salmonella enterica (85%) were quite conserved but the occurrence of inter-species polymorphism was demonstrated. The OppA gene was detected in 58 diarrheogenic E. coli, Shigella and Salmonella strains. Using a recombinant OppA protein produced in E. coli, specific polyclonal sera were generated and successfully applied in the immunological detection of the proteins expressed by the tested strains. Thus, we conclude that the OppA protein is present and conserved among species and strains of the three test Enterobacteriaceae genera.

Diese Arbeit beschäftigt sich der Modulation und Regelung von Mehrpunktstromrichtern zum Antrieb elektrischer Maschinen unter Nutzung optimierter Pulsmuster. Ziel der Arbeit ist es, das Potential und die Grenzen der Modulation mit optimierten Pulsmustern unter der Randbedingung der heute vorhandenen Softwareframeworks und Rechentechnik aufzuzeigen. Darüber hinaus soll dem Leser ein gesamtheitlicher Überblick über die optimierten Pulsmuster vermittelt werden. Ausgehend vom Stand der Technik der verbreiteten Arten der Modulation werden die optimierten Pulsmuster eingeführt. Für die notwendige Berechnung der Pulsmuster als Lösung einer Optimierungsaufgabe wird ein allgemeines Konzept der mathematischen Beschreibung vorgestellt. Darauf basierend werden zehn heute verfügbare numerische Löser auf ihre Konvergenz bezüglich der Lösung des gestellten Problems untersucht. Die Ergebnisse zeigen, dass es möglich ist, optimierte Pulsmuster mit Frequenzverhältnissen mf ≤ 21 online zu berechnen und dass geeignete Löser auch bei mf ≫ 50 sicher konvergieren. Eine Analyse der gefundenen Lösungen zeigt, dass der von trägerbasierten Modulationen bekannte lineare Zusammenhang zwischen mittlerer Schaltfrequenz und Schaltverlusten bei den optimierten Pulsmustern nicht gegeben ist. Darauf aufbauend wird ein neuer Algorithmus zur Wahl verlustminimierter Pulsmuster erarbeitet. Es zeigt sich, dass dessen Einsatz auch bei mf ≫ 21 gegenüber der Raumzeigermodulation zu einer signifikanten Reduktion der Schaltverluste (ca. 20%) führt. Mit den Grundlagen der Berechnung und der Analyse der Eigenschaften der optimierten Pulsmuster, wird basierend auf dem Stand der Technik ein neuartiger lastunabhängiger Modulator entwickelt. Dieser kompensiert die Unstetigkeiten der Pulsmusterwechsel durch Regelung des Integrals des harmonischen Inhalts der Pulsmuster. Aufbauend auf diesem neuartigen Modulator wird eine parameterrobuste Maschinenregelung entworfen. Diese weist eine Dead-Beat-Dynamik der Regelung des elektrischen Momentes einer angeschlossenen Maschine auf und ermöglicht im stationären Zustand, im Gegensatz zu den bestehenden Konzepten, die Ausgabe eines unveränderten Pulsmusters. Damit wird die angestrebte minimierte Stromwelligkeit erreicht. Im letzten Teil der Arbeit wird der Einfluss einer Modulation mit optimierten Pulsmustern auf den Symmetrierungsvorgang eines selbstgeführten Dreipunkt-UStromrichter (3L-NPC-VSC) untersucht. Dabei wird eine neue Methode der Reduktion der dynamischen Zwischenkreiswelligkeit, sowie eine neuartige, in allen Arbeitspunkten stabile, Methode der statischen Zwischenkreissymmetrierung präsentiert. Alle erarbeiteten Algorithmen wurden mit Hilfe von Simulationen und Experimenten verifiziert.:1 Einleitung 1 1.1 Inhalt und Motivation der vorliegenden Arbeit 2 1.2 Experimenteller Versuchsstand 4 1.3 Verwendete Grundlagen und Kennwerte 6 1.3.1 Fourieranalyse 6 1.3.2 Laplace-Transformation 7 1.3.3 Gütekriterien 8 2 Modulation 9 2.1 Klassifikation der Generierung der Pulsmuster 9 2.2 Modulationsverfahren 11 2.2.1 Trägerbasierte Pulsweitenmodulation 11 2.2.2 Raumzeigermodulation 22 2.2.3 Optimierte Pulsmuster 25 3 Optimierte Pulsmuster 29 3.1 Optimierungskriterien 30 3.1.1 Gewichtetes Gesamt-Oberschwingungsverhältnis 30 3.1.2 Gesamt-Oberschwingungsverhältnis 30 3.1.3 Minimale Drehmomentwelligkeit 31 3.1.4 Individuelle Wichtung der Harmonischen 32 3.1.5 Verlustminimierung in der Last 33 3.1.6 Schaltverlustminimierung der Halbleiter des Umrichters 34 3.2 Formulierung der Optimierungsaufgabe der optimierten Pulsmuster 35 3.2.1 Berechnung der Fourierkoeffizienten 36 3.2.2 Notwendige Nebenbedingungen der Optimierung 38 3.3 Vergleich von Algorithmen der nichtlinearen Optimierung 38 3.3.1 Vergleich verschiedener Lösungsmethoden 39 3.3.2 Definition des für den Vergleich genutzten Problems 43 3.3.3 Dauer der Berechnung der lokalen Minima 44 3.3.4 Vergleich der lokalen Minima der verschiedenen Löser 45 3.3.5 Berechnung verlustminimaler optimierter Pulsmuster 46 3.3.6 Untersuchungen zur Auswahl der lokalen Minima 47 3.3.7 Vergleich der optimierten Pulsmuster mit SVM und CB-Modulation 56 4 Stand der Technik der Regelung von Drehstrommaschinen 60 4.1 Grundlagen der Modellierung der Asynchronmaschine 60 4.2 Klassische Ansätze der Regelung elektrischer Maschinen 62 4.2.1 Feldorientierte Regelung 62 4.2.2 Direkte Selbstregelung 69 4.2.3 Direkte Momentenregelung 72 4.2.4 Vergleich der vorgestellten klassischen Regelungsarten 75 4.3 Regelung mit optimierten Pulsmustern auf Basis der Feldorientierung 76 4.3.1 Dynamischer Modulationsfehler durch unstetige Pulsmuster 76 4.3.2 Direkte Pulsmustermodifikation 80 4.3.3 Behandlung des dynamischen Modulationsfehlers 84 4.4 Geschlossener Regelkreis 86 4.5 Regelung mit optimierten Pulsmustern auf Basis der DSC 92 4.5.1 Eigenschaften der vorgestellten Pulserzeugungsarten 94 4.5.2 Dynamischen Eigenschaften der vorgestellten Regelungsstrukturen 95 5 Verallgemeinerte Konzepte zur Nutzung optimierter Pulsmuster 98 5.1 Implementierung eines allgemeingültigen OPP-Modulators 98 5.2 Behandlung des harmonischen Anteils der Pulsmuster 104 5.3 Modulation und Modifikation der Pulsmuster bei hohem mf 105 5.4 Dead-Beat-Control auf Basis der Pulsmustermodifikation 108 5.5 Maschinen-Beobachter 109 5.5.1 Beobachter der Asynchronmaschine 111 5.5.2 Beobachter der permanenterregten Synchronmaschine 114 5.6 Geschlossener Statorflussregelkreis 115 5.6.1 Untersuchung der Sensitivität des Modells 119 5.7 Entwurf der übergeordneten Regelkreise 123 5.7.1 Entwurf des Rotorflussreglers 125 5.7.2 Entwurf des Drehzahlreglers 126 5.7.3 Begrenzung des Statorstromes 127 5.7.4 Simulative und experimentelle Ergebnisse 127 6 Zwischenkreissymmetrierung des 3L-NPC-VSC bei OPP-Modulation 135 6.1 Der Neutralpunktstrom 135 6.2 Minimierung der Neutralpunktstromwelligkeit 138 6.3 Aktive Symmetrierung 140 6.4 Integration der Regelung der Zwischenkreissymmetrie 154 7 Zusammenfassung 158 Literatur 161 Abkürzungsverzeichnis 177 Symbolverzeichnis 178 / This thesis deals with the modulation and control of multilevel converters as electrical drives using an optimized pulse pattern (OPP) modulation scheme. The aim of the work is to determine the potential and the limits of the modulation using OPPs, considering state-of-the-art software frameworks und computing technology. Furthermore the reader shell get a holistic overview of all aspects regarding the use of OPPs. Starting with the state-of-the-art of the most popular modulation schemes and their characteristics the optimized pulse patterns are introduced. A general mathematical formulation, which describes the OPP calculation as minimization problem, is shown. With this formulation, ten implementations of nonlinear constraint minimization algorithms are analyzed with regard to the convergence behavior. It is shown, that OPP can be calculated online for frequency ratios mf ≫ 21. Further, some algorithms converge reliable also for mf ≫ 50. Afterwards, the solutions of the minimization of the weighted total harmonic distortion (WTHD) problem are analyzed. It is shown, that the linear relationship between the averaged switching frequency and the switching loss, which is known from carrier based modulation schemes, does not apply for OPPs. A new method to find loss optimized pulse patterns is proposed. With this method the modulation using OPPs can reduce the converter switching losses in comparison to space vector modulation significantly (20%) also for mf ≫ 21. Based on the analysis of the found OPP solutions a novel modulator, which is independent of the parameters of the load, is proposed. This modulator compensates the discontinuities due to the pulse pattern changes by controlling the integral of the harmonic content of the modulator output. Based on this modulator a new parameter robust machine control was developed. This concept shows a dead-beat-dynamic of the control of the electrical torque and uses in contrast to state-of-the-art concepts the unmodified OPP in steady state, which leads to a minimal load current ripple. The last part of the thesis deals with the influence of using an OPP modulation on the DC-link balancing of a Three-Level Neutral-Point-Clamped Voltage-Source-Converter (3L-NPC-VSC). A new method to reduce the dynamic neutral-pointpotential-ripple as well as a new stable static balancing method are proposed. All proposed algorithms and methods are verified by simulation and experiment.:1 Einleitung 1 1.1 Inhalt und Motivation der vorliegenden Arbeit 2 1.2 Experimenteller Versuchsstand 4 1.3 Verwendete Grundlagen und Kennwerte 6 1.3.1 Fourieranalyse 6 1.3.2 Laplace-Transformation 7 1.3.3 Gütekriterien 8 2 Modulation 9 2.1 Klassifikation der Generierung der Pulsmuster 9 2.2 Modulationsverfahren 11 2.2.1 Trägerbasierte Pulsweitenmodulation 11 2.2.2 Raumzeigermodulation 22 2.2.3 Optimierte Pulsmuster 25 3 Optimierte Pulsmuster 29 3.1 Optimierungskriterien 30 3.1.1 Gewichtetes Gesamt-Oberschwingungsverhältnis 30 3.1.2 Gesamt-Oberschwingungsverhältnis 30 3.1.3 Minimale Drehmomentwelligkeit 31 3.1.4 Individuelle Wichtung der Harmonischen 32 3.1.5 Verlustminimierung in der Last 33 3.1.6 Schaltverlustminimierung der Halbleiter des Umrichters 34 3.2 Formulierung der Optimierungsaufgabe der optimierten Pulsmuster 35 3.2.1 Berechnung der Fourierkoeffizienten 36 3.2.2 Notwendige Nebenbedingungen der Optimierung 38 3.3 Vergleich von Algorithmen der nichtlinearen Optimierung 38 3.3.1 Vergleich verschiedener Lösungsmethoden 39 3.3.2 Definition des für den Vergleich genutzten Problems 43 3.3.3 Dauer der Berechnung der lokalen Minima 44 3.3.4 Vergleich der lokalen Minima der verschiedenen Löser 45 3.3.5 Berechnung verlustminimaler optimierter Pulsmuster 46 3.3.6 Untersuchungen zur Auswahl der lokalen Minima 47 3.3.7 Vergleich der optimierten Pulsmuster mit SVM und CB-Modulation 56 4 Stand der Technik der Regelung von Drehstrommaschinen 60 4.1 Grundlagen der Modellierung der Asynchronmaschine 60 4.2 Klassische Ansätze der Regelung elektrischer Maschinen 62 4.2.1 Feldorientierte Regelung 62 4.2.2 Direkte Selbstregelung 69 4.2.3 Direkte Momentenregelung 72 4.2.4 Vergleich der vorgestellten klassischen Regelungsarten 75 4.3 Regelung mit optimierten Pulsmustern auf Basis der Feldorientierung 76 4.3.1 Dynamischer Modulationsfehler durch unstetige Pulsmuster 76 4.3.2 Direkte Pulsmustermodifikation 80 4.3.3 Behandlung des dynamischen Modulationsfehlers 84 4.4 Geschlossener Regelkreis 86 4.5 Regelung mit optimierten Pulsmustern auf Basis der DSC 92 4.5.1 Eigenschaften der vorgestellten Pulserzeugungsarten 94 4.5.2 Dynamischen Eigenschaften der vorgestellten Regelungsstrukturen 95 5 Verallgemeinerte Konzepte zur Nutzung optimierter Pulsmuster 98 5.1 Implementierung eines allgemeingültigen OPP-Modulators 98 5.2 Behandlung des harmonischen Anteils der Pulsmuster 104 5.3 Modulation und Modifikation der Pulsmuster bei hohem mf 105 5.4 Dead-Beat-Control auf Basis der Pulsmustermodifikation 108 5.5 Maschinen-Beobachter 109 5.5.1 Beobachter der Asynchronmaschine 111 5.5.2 Beobachter der permanenterregten Synchronmaschine 114 5.6 Geschlossener Statorflussregelkreis 115 5.6.1 Untersuchung der Sensitivität des Modells 119 5.7 Entwurf der übergeordneten Regelkreise 123 5.7.1 Entwurf des Rotorflussreglers 125 5.7.2 Entwurf des Drehzahlreglers 126 5.7.3 Begrenzung des Statorstromes 127 5.7.4 Simulative und experimentelle Ergebnisse 127 6 Zwischenkreissymmetrierung des 3L-NPC-VSC bei OPP-Modulation 135 6.1 Der Neutralpunktstrom 135 6.2 Minimierung der Neutralpunktstromwelligkeit 138 6.3 Aktive Symmetrierung 140 6.4 Integration der Regelung der Zwischenkreissymmetrie 154 7 Zusammenfassung 158 Literatur 161 Abkürzungsverzeichnis 177 Symbolverzeichnis 178

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This study presents a holistic view of which factors small and medium-sized enterprises (SMEs) have to consider, in moving their customer order decoupling point (CODP) further from the customer, thereby becoming more customized. The study also investigate whether SMEs and larger enterprises differ in the strategic questions relating to what influences an enterprise to become more customized, which prerequisites are required and which problems enterprises should anticipate and prepare for. These questions are important, given that strategic change is challenging, and can take considerable time to accomplish; it therefore needs to be based on the right decisions. This study is motivated by the fact that the markets SMEs are selling to tend to become more and more complex and harder to anticipate. Increased globalisation and use of IT and ICT have lead to greater uncertainty in customer demand. At the same time customers have ever more demanding needs and specifications; if these are not met, they will go elsewhere rather than reducing or adapting them. This complexity requires a more customized production and is a way to gain commercial advantages.       Customised production includes many benefits such as reduced uncertainty, by producing totally customized products less capital bound is tied up. But meanwhile many challenges such as reduced production efficiency, furthermore flexibility must be increased and higher demands on communications and IT systems are often necessary. The study starts with a wide and thorough theoretical overhaul around the movement of the CODP, but also addresses other parts of the organization to get the all-important big picture. This theoretical work is leading to a work-model which is used in six interviews within SMEs. In order to get a thorough picture, the enterprises that take part in the study are from different line of business and have from 18 to 235 employees. During these interviews, conducted on a single occasion per company, the model and related questions are discussed. Thereby an analysis of the interviews and the theory is done, with the model as the starting-point.   The result of this study is a basic model, which SMEs can use as an analytical tool, and a checklist, to facilitate a move towards a make-to-order manufacturing strategy, thereby gaining more flexibility. The study provides a basic generic framework which can be adapted and tailored by the company in question to see which parts are relevant to specific circumstances.

In this thesis, the focus is on studying BaZrO3-BaCeO3 based proton conductors due to that they represent very promising proton conductors to be used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs). Here, dense BaZr0.5Ce0.3Y0.2O3-δ (BZCY532) ceramics were selected as the major studied materials. These ceramics were prepared by different sintering methods and doping strategies. Based on achieved results, the thesis work can simply be divided into the following parts: 1) An improved synthesis method, which included a water-based milling procedure followed by a freeze-drying post-processing, was presented. A lowered calcination and sintering temperature for a Hf0.7Y0.3O2-δ (YSH) compound was achieved. The value of the relative density in this work was higher than previously reported data. It is also concluded that this improved method can be used for mass-production of ceramics. 2) As the solid-state reactive sintering (SSRS) represent a cost-effective sintering method, the sintering behaviors of proton conductors BaZrxCe0.8-xLn0.2O3-δ (x = 0.8, 0.5, 0.1; Ln = Y, Sm, Gd, Dy) during the SSRS process were investigated. According to the obtained results, it was found that the sintering temperature will decrease, when the Ce content increases from 0 (BZCLn802) to 0.3 (BZCLn532) and 0.7 (BZCLn172). Moreover, the radii of the dopant ions similar to the radii of Zr4+ or Ce4+ ions show a better sinterability. This means that it is possible to obtain dense ceramics at a lower temperature. Moreover, the conductivities of dense BZCLn532 ceramics were determined. The conductivity data indicate that dense BZCY532 ceramics are good candidates as either oxygen ion conductors or proton conductors used for ITSOFCs. 3) The effect of NiO on the sintering behaviors, morphologies and conductivities of BZCY532 based electrolytes were systematically investigated. According to the achieved results, it can be concluded that the dense BZCY532B ceramics (NiO was added during ball-milling before a powder mixture calcination) show an enhanced oxygen and proton conductivity. Also, that BZCY532A (NiO was added after a powder mixture calcination) and BZCY532N (No NiO was added in the whole preparation procedures) showed lower values. In addition, dense BZCY532B and BZCY532N ceramics showed only small electronic conductivities, when the testing temperature was lower than 800 ℃. However, the BZCY532A ceramics revealed an obvious electronic conduction, when they were tested in the range of 600 ℃ to 800 ℃. Therefore, it is preferable to add the NiO powder during the BZCY532 powder preparation, which can lower the sintering temperature and also increase the conductivity. 4) Dense BZCY532 ceramics were successfully prepared by using the Spark Plasma Sintering (SPS) method at a temperature of 1350 ℃ with a holding time of 5 min. It was found that a lower sintering temperature (&lt; 1400 ℃) and a very fast cooling rate (&gt; 200 ℃/min) are two key parameters to prepare dense BZCY532 ceramics. These results confirm that the SPS technique represents a feasible and cost-effective sintering method to prepare dense Ce-containing BaZrO3-BaCeO3 based proton conductors. 5) Finally, a preliminary study for preparation of Ce0.8Sm0.2O2-δ (SDC) and BZCY532 basedcomposite electrolytes was carried out. The novel SDC-BZCY532 based composite electrolytes were prepared by using the powder mixing and co-sintering method. The sintering behaviors, morphologies and ionic conductivities of the composite electrolytes were investigated. The obtained results show that the composite electrolyte with a composition of 60SDC-40BZCY532 has the highest conductivity. In contrast, the composite electrolyte with a composition of 40SDC-60BZCY532 shows the lowest conductivity. In summary, the results show that BaZrO3-BaCeO3 based proton-conducting ceramic materials represent very promising materials for future ITSOFCs electrolyte applications. / <p>QC 20150423</p>