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Dissertations / Theses on the topic 'Active Neutral Point Clamped'

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Published: 4 June 2025
Last updated: 23 June 2025

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1

Van, Greunen Corneluis Erasmus. "Neutral-point-clamped shunt active filter." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1265.

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2

Sprenger, Michael. "Untersuchung des Dreipunkt – Neutral Point Clamped – Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Niederspannungswindkraftanwendungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-172806.

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Das Ziel der Arbeit war die Untersuchung eines neuartigen Phasenbausteins mit der Topologie des Dreipunkt – Neutral Point Clamped – Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Windkraftanwendungen. Wichtige Anforderungen an den Phasenbaustein und daraus resultierende Herausforderungen, sowie Lösungen für ausgewählte Teilprobleme werden präsentiert. Um die Vorteile des 3L-NPC-VSC für Hersteller von Windkraftanlagen zugänglich zu machen, ist es sinnvoll, einen neuartigen Phasenbaustein zu entwickeln. Der Phasenbaustein soll einfach in Systeme zu integrieren sein, in denen gegenwärtig Zweipunktstromrichter (2L-VSC) zum Einsatz kommen. Da sich Modulation, Zwischenkreisbalancierung und Kurzschlussschutz vom 2L-VSC unterscheiden, soll der Phasenbaustein diese Herausforderungen eigenständig bewältigen. Die Arbeit beschreibt die Konzeption eines solchen Phasenbausteins und behandelt insbesondere die Modulation, die Zwischenkreisbalancierung und den Kurzschlussschutz des 3L-NPC-VSC. Ein Vergleich verschiedener Modulationsverfahren wurde durchgeführt und die am besten geeigneten Verfahren für die Implementation in den Phasenbaustein ausgewählt. Eine Anforderung war, dass dieser Signale einer übergeordneten Regelung verarbeiten kann, welche für einen 2L-VSC berechnet wurden. Ein Überblick der Zwischenkreisbalancierungsverfahren zeigte, dass nahezu alle den Nachteil einer zusätzlich benötigten Strommessung haben. Die Untersuchung einer neuen an der Professur Leistungselektronik der TU Dresden entwickelten Methode ohne den Bedarf der Strommessung zeigte, dass diese anwendbar ist. Der Algorithmus wurde simuliert, implementiert und experimentell getestet und zeigte gute Resultate. Die Aufgabe eines komplett unabhängigen Kurzschlussschutzes war die schwierigste. Alle möglichen Fehler innerhalb eines Moduls wurden analysiert und kategorisiert. Einige Fehlertypen können innerhalb einer Phase behandelt werden. Entsprechende Algorithmen wurden entwickelt und getestet. Allerdings gibt es Fehlertypen, die nicht durch die Steuerung einer einzelnen Phase behandelt werden können. Eine schnelle Kommunikation zwischen den drei Phasen des Konverters wäre notwendig. Alternativ könnte eine übergeordnete Steuerung diese Fehler behandeln. Zum Schluss wurde ein Demonstrator des Phasenbausteins aufgebaut und experimentell untersucht. Einige Messergebnisse werden gezeigt, um die Funktion zu verifizieren.
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3

Andler, Daniel [Verfasser]. "Experimental Investigation of Three-Level Active Neutral Point Clamped Voltage Source Converters using Integrated Gate-Commutated Thyristors / Daniel Andler." München : Verlag Dr. Hut, 2014. http://d-nb.info/1051550092/34.

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4

Andler, Osorio Daniel Andrés [Verfasser]. "Experimental Investigation of Three-Level Active Neutral Point Clamped Voltage Source Converters using Integrated Gate-Commutated Thyristors / Daniel Andler." München : Verlag Dr. Hut, 2014. http://d-nb.info/1051550092/34.

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5

Marzoughi, Alinaghi. "Investigating Impact of Emerging Medium-Voltage SiC MOSFETs on Medium-Voltage High-Power Applications." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/81822.

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For decades, the Silicon-based semiconductors have been the solution for power electronics applications. However, these semiconductors have approached their limits of operation in blocking voltage, working temperature and switching frequency. Due to material superiority, the relatively-new wide-bandgap semiconductors such as Silicon-Carbide (SiC) MOSFETs enable higher voltages, switching frequencies and operating temperatures when compared to Silicon technology, resulting in improved converter specifications. The current study tries to investigate the impact of emerging medium-voltage SiC MOSFETs on industrial motor drive application, where over a quarter of the total electricity in the world is being consumed. Firstly, non-commercial SiC MOSFETs at 3.3 kV and 400 A rating are characterized to enable converter design and simulation based on them. In order to feature the best performance out of the devices under test, an intelligent high-performance gate driver is designed embedding required functionalities and protections. Secondly, total of three converters are targeted for industrial motor drive application at medium-voltage and high-power range. For this purpose the cascaded H-bridge, the modular multilevel converter and the 5-L active neutral point clamped converters are designed at 4.16-, 6.9- and 13.8 kV voltage ratings and 3- and 5 MVA power ratings. Selection of different voltage and power levels is done to elucidate variation of different parameters within the converters versus operating point. Later, comparisons are done between the surveyed topologies designed at different operating points based on Si IGBTs and SiC MOSFETs. The comparison includes different aspects such as efficiency, power density, semiconductor utilization, energy stored in converter structure, fault containment, low-speed operation capability and parts count (for a measure of reliability). Having the comparisons done based on simulation data, an H-bridge cell is implemented using 3.3 kV 400 A SiC MOSFETs to evaluate validity of the conducted simulations. Finally, a novel method is proposed for series-connecting individual SiC MOSFETs to reach higher voltage devices. Considering the fact that currently the SiC MOSFETs are not commercially available at voltages higher above 1.7 kV, this will enable implementation of converters using medium-voltage SiC MOSFETs that are achieved by stacking commercially-available 1.7 kV MOSFETs. The proposed method is specifically developed for SiC MOSFETs with high dv/dt rates, while majority of the existing solutions could only work merely with slow Si-based semiconductors.<br>Ph. D.
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6

Lee, Meng Yeong. "Three-level neutral-point-clamped matrix converter topology." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10987/.

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Matrix converter is a direct AC-AC converter topology that is able to directly convert energy from an AC source to an AC load without the need of a bulky and limited lifetime energy storage element. Due to the significant advantages offered by matrix converter, such as adjustable power factor, capability of regeneration and high quality sinusoidal input/output waveforms, matrix converter has been one of the AC – AC topologies that receive extensive research attention for being an alternative to replace traditional AC-DC-AC converters in the variable voltage and variable frequency AC drive applications. Multilevel matrix converter is an emerging topology that integrates the multilevel concept into the matrix converter topology. Having the ability to generate multilevel output voltages, the multilevel matrix converter is able to produce better quality output waveforms than conventional matrix converter in terms of harmonic content, but at the cost of higher number of power semiconductor device requirement and more complicated modulation strategy. In this research work an indirect three-level sparse matrix converter is proposed. The proposed converter is a hybrid combination between a simplified three-level neutral-point-clamped voltage source inverter concept and an indirect matrix converter topology. This multilevel matrix converter topology has a simpler circuit configuration and is able to generate three-level output voltages, making this topology an attractive option in industrial applications. In this work a comprehensive simulation study is carried out to investigate the operation of the proposed converter. The performance of the proposed converter is compared to the conventional indirect matrix converter topology and a multilevel neutral-point- clamped matrix converter in order to identify the advantages and disadvantages offered by the proposed converter. A study of the semiconductor losses in the indirect three-level sparse matrix converter is also included. Finally, the operation of the proposed converter is experimentally validated using a laboratory prototype.
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7

Salagae, Isaac Mahijoko. "Natural balancing of the neutral-point-clamped converter." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53514.

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Thesis (MScEng)--University of Stellenbosch, 2003.<br>ENGLISH ABSTRACT: The three-level neutral-point-clamped(NPC) converter, being a widely used multilevel inverter, received a lot of attention recently due to problems associated with de-link capacitor voltage balancing. There are mainly two problems associated with the neutralpoint voltage of the NPC inverter: 1. At high modulation indices a low frequency ripple occurs on the neutral-point voltage. 2. Steady-state unbalance in the neutral-point voltage may arise due to a variety of factors including component imperfections, transients and other non-idealities and imbalances. In this thesis we study the balancing problem with focus on the steady-state imbalance. This is achieved by a systematic and mathematically rigorous study of the natural balancing mechanisms of the three-level three-phase NPC inverter. Orthogonality of two sets of switching spectra in the frequency domain would imply that the DC-bus voltages balance in the steady state. This is done through mathematical analysis using Carrara's PWM strategy of alternative phase opposition disposition(APOD), phase opposition disposition( POD) and phase disposition(PD); and Bennet's geometric model for double Fourier series adapted for use with power converter systems by Bowes. The theory is verified through simulation.<br>AFRIKAANSE OPSOMMING: Aangesien die drie-vlak, geklemde, neutrale-punt omsetter(NPC) 'n algemene omsetter konfigurasie is, is daar onlangs baie aandag gegee aan die probleme wat geassosieer word met die balansering van die omsetter se gelykstroombuskapasitorspanning. Die twee hoof probleme wat gepaart gaan met die neutraalpuntspanning van die NPC omsetter is: 1. Met 'n ho modulasie-indeks ontstaan daar 'n lae frekwensie rippel op die neutralepuntspanning. 2. 'n Bestendige toestand wanbalans van die neutrale-puntspanning kan ontstaan as gevolg van 'n verskeidenheid faktore, onder andere komponent nie-idealiteite, oorgangs- en ander wanbalanse. In hierdie tesis word op die bestendige-toestandwanbalans gefokus. Dit word gedoen deur middel van die neutraalbalanseeringsmeganisme van die drie-vlak, drie-fase NPC omsetter, sistematies en gedetaileerd wiskundig te bestudeer. In die bestendige toestand sal orgonaliteit van twee stelle skakel spektras in die frekwensie gebied, GS-bus spanning balans impliseer. Dit word wiskundig geanaliseer deur gebruik te maak van Carrara se alternatiewe fase opposiesie disposisie (APOD), fase oposisie disposisie (POD) en fase disposisie(PD), puls-wydte modulasie strategie, asook Bennet se geometriese modelle vir die dubbel Fourier reeks wat aangepas is vir drywingsomsetters deur Bowes. Ten slotte is die teorie geverifieer deur simulasies.
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8

Floten, Sveinung, and Tor Stian Haug. "Modulation Methods for Neutral-Point-Clamped Three-Level Inverter." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10882.

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<p>Multilevel converters have seen an increasing popularity in the last years for medium- and high-voltage applications. The most popular has been the three-level neutral clamped converter and still research is going on to improve the control of it. This master thesis was a continuation of the specialization project fall 2009. The main topics of current thesis were to further investigate the DC-bus balancing issues, compare symmetrical (one sampling per triangular wave) and asymmetrical (sampling at the top and bottom of the triangular wave) modulation, derive current equations for Space Vector and Double-Signal, improve output voltage in overmodulation and be able to DC-bus balance, and to implement the methods in the laboratory. Models of the three-level converter were made in the specialization project in both PSCAD and SIMULINK and further studies of the DC-bus balance were also made in this master thesis. None of the methods showed problems to regulate the DC-bus voltage when there was different capacitor values and unsymmetrical load. A PI controller was introduced for Space Vector but it did not show better performance than a regular P regulator. Asymmetrical modulation showed a clearly better performance than symmetrical modulation when the switching frequency was low compared to the fundamental frequency, especially for Space Vector. The 1st harmonic line-to-line voltage was closer to the wanted value and the THDi was significantly lower. Simulations also showed that the THDi can vary significantly depending on at which angle the first sampling is done. This is most clear for asymmetrical Space Vector modulation, but also for the other cases this pattern occurs. By implementing an overmodulation algorithm the amplitude of the 1st harmonic output voltage was closer to what was desired. Simulations showed how important it was to have three phase sampling symmetry in overmodulation. By having a wrong switching frequency the line-to-line output voltage dropped down to 2.06 when operating in six-step, when the wanted output value should be 2.205. Hence there is a quite large mismatch and the converter is sensitive to the switching frequency when it is operating in the higher modulation area. The balancing algorithm introduced for overmodulation is able to remove an initial offset without a notable change the 1st harmonic output. Both Space Vector and Double-Signal were tested in the laboratory with two separated DC-sources. Asymmetrical and Symmetrical modulation were tested and so was also overmodulation. The laboratory results confirmed the simulated results, but since the switching was not synchronized in the laboratory, some errors occurred.</p>
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9

Busquets, Monge Sergio. "A novel pulsewidth modulation for the comprehensive neutral-point voltage control in the three-level three-phase neutral-point-clamped dc-ac converte." Doctoral thesis, Universitat Politècnica de Catalunya, 2006. http://hdl.handle.net/10803/6372.

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Las topologías de convertidores multinivel han recibido una atención especial durante las dos últimas décadas debido a sus notables ventajas en aplicaciones de alta potencia y media/alta tensión. En estas topologías, y comparadas con el convertidor tradicional de dos niveles, el voltaje que soporta cada dispositivo semiconductor es menor, evitando los problemas asociados con la interconexión serie de dispositivos. La distorsión armónica en la tensión de salida es también menor y la eficiencia mayor. Pero incorporan un número superior de dispositivos semiconductores y la estrategia de modulación resultante es, por tanto, más compleja.<br/>Entre estas topologías, el convertidor cc-ca de tres niveles trifásico con conexión al punto neutro del bus de cc es probablemente el más popular. La aplicación a este convertidor de técnicas de modulación convencionales causa una oscilación de la tensión del punto neutro de baja frecuencia (tres veces la frecuencia fundamental de la tensión de salida). Esta oscilación, a su vez, supone un incremento del estrés de tensión de los dispositivos y provoca la aparición de armónicos de baja frecuencia en la tensión de salida.<br/>Esta tesis presenta una nueva técnica de modulación del pulso de conducción de los dispositivos semiconductores para convertidores de tres niveles trifásicos con conexión a punto neutro, capaz de conseguir un control completo de la tensión del punto neutro con una distorsión armónica reducida en la tensión de salida alrededor de la frecuencia de conmutación. Esta nueva técnica de modulación, basada en la definición de unos vectores espaciales virtuales, garantiza el equilibrado de la tensión del punto neutro con cualquier carga (lineal o no, cualquier factor de potencia) y para todo el rango de tensión de salida, con el único requisito de que la suma de corrientes de fase sea nula.<br/>Las características de la técnica de modulación propuesta y sus beneficios con respecto a otras modulaciones se han verificado a través de simulaciones y experimentos tanto en lazo abierto como en lazo cerrado.<br>Multilevel converter topologies have received special attention during the last two decades due to their significant advantages in high-power medium- and high-voltage applications. In these topologies, and compared to the previous two-level case, the voltage across each semiconductor is reduced, avoiding the problems of the series interconnection of devices. The harmonic distortion of the output voltage is also diminished and the converter efficiency increases. But a larger number of semiconductors is needed and the modulation strategy to control them becomes more complex.<br/>Among these topologies, the three-level three-phase neutral-point-clamped voltage source inverter is probably the most popular. The application of traditional modulation techniques to this converter causes a low frequency (three times the fundamental frequency of the output voltage) oscillation of the neutral-point voltage. This, in turn, increases the voltage stress on the devices and generates low-order harmonics in the output voltage.<br/>This thesis presents a novel pulsewidth modulation for the three-level three-phase neutral-point-clamped converter, able to achieve a complete control of the neutral-point voltage while also having a low output voltage distortion at around the switching frequency. The new modulation, based on a virtual space vector concept, guarantees the balancing of the neutral-point voltage for any load (linear or nonlinear, any load power factor) over the full range of converter output voltage, the only requirement being that the addition of the output three-phase currents equals zero.<br/>The performance of this modulation approach and its benefits over other previously proposed solutions are verified through simulation and experiments in both open- and closed-loop converter configurations.
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10

Al, Shammeri Bashar Mohammed Flayyih. "A novel induction heating system using multilevel neutral point clamped inverter." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/8305.

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This thesis investigates a novel DC/AC resonant inverter of Induction Heating (IH) system presenting a Multilevel Neutral Point Clamped (MNPCI) topology, as a new part of power supply design. The main function of the prototype is to provide a maximum and steady state power transfer from converter to the resonant load tank, by achieving zero current switching (ZCS) with selecting the best design of load tank topology, and utilizing the advantage aspects of both the Voltage Fed Inverter (VFI) and Current Fed Inverter (CFI) kinds, therefore it can considered as a hybrid-inverter (HVCFI) category . The new design benefits from series resonant inverter design through using two bulk voltage source capacitors to feed a constant voltage delivery to the MNPCI inverter with half the DC rail voltage to decrease the switching losses and mitigate the over voltage surge occurred in inverter switches during operation which may cause damage when dealing with high power systems. Besides, the design profits from the resonant load topology of parallel resonant inverter, through using the LLC resonant load tank. The design gives the advantage of having an output current gain value of about Quality Factor (Q) times the inverter current and absorbs the parasitic components. On the contrary, decreasing inverter current means decreasing the switching frequency and thus, decreasing the switching losses of the system. This aspect increases the output power, which increases the heating efficiency. In order for the proposed system to be more reliable and matches the characteristics of IH process , the prototype is modelled with a variable LLC topology instead of fixed load parameters with achieving soft switching mode of ZCS and zero voltage switching (ZVS) at all load conditions and a tiny phase shift angle between output current and voltage, which might be neglected. To achieve the goal of reducing harmonic distortion, a new harmonic control modulation is introduced, by controlling the ON switching time to obtain minimum Total Harmonic Distortion (THD) content accompanied with optimum power for heating energy.
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11

Ustuntepe, Bulent. "A Novel Two-parameter Modulation And Neutral Point Potential Control Method For The Three-level Neutral Point Clamped Inverter." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606928/index.pdf.

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In this thesis, the neutral point potential drift/fluctuation of the three-level neutral point clamped inverter is analyzed and a novel control algorithm, the two-parameter PWM method is proposed to confine the neutral point potential variation to a very small range. The two-parameter PWM method provides superior neutral point potential control performance even with small DC bus capacitors. The method is based on PWM pulse pattern modification and requires no additional hardware. Detailed analytical models of the neutral point current and potential as a function of the modulation parameters are established and the neutral point potential behavior is thoroughly investigated. Based on the study, the deficiency of the known methods is illustrated and the two-parameter PWM method is developed and its superior performance demonstrated. The performance of the two-parameter PWM method is verified by means of computer simulations utilizing both the per-PWM-cycle average model and the detailed model of the inverter. The results are supported by laboratory experiments involving both an R-L load and an induction motor drive.
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12

Somogyi, Chad Alexander. "Common mode voltage mitigation strategies using PWM in neutral-point-clamped multilevel inverters." Thesis, Marquette University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1594317.

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<p> Over the last several decades, there has been consistent growth in the research and development of multilevel voltage-source inverter-based adjustable speed motor drives (ASDs) as a result of low cost, high reliability power semiconductors. The three-level neutral-point-clamped (NPC) ASD is a popular multilevel inverter used in low and medium voltage applications because of its ability to produce lower levels of total harmonic distortion (THD) and withstand higher voltages while preserving the rated output power compared to two-level ASDs.</p><p> As with other voltage-source inverters, three-level NPC ASDs produce common-mode voltage (CMV) that can cause motor shaft voltages, bearing currents, and excess voltage stresses on motor windings, resulting in the deterioration of motor bearings and insulation. Furthermore, the CMV and resultant currents can generate electromagnetic interference that can hinder the operation of sensitive control electronics. In this thesis, three carrier-based, three-level pulse-width-modulation (PWM) strategies were investigated to examine the levels of CMV, common-mode current, and <i>dv/dt</i> produced by the three-level NPC ASD. Additionally, the effects that each PWM strategy has on the THD in the output waveforms, as well as the total switching and conduction losses were analyzed through software simulation programs using a resistive-inductive load over a range of modulation indices. The first of the three methods, in-phase disposition sub-harmonic PWM (PD-SPWM), was verified experimentally using a laboratory-scale, 7.5 kVA three-level NPC ASD prototype.</p><p> It was determined that PD-SPWM produced the highest CMV amplitude of one-third the dc bus voltage, but the lowest values of differential-mode dv/dt, THD, and drive losses. The second strategy, phase-opposition (PO)-SPWM, reduced the CMV amplitude to one-sixth the dc bus voltage, at the cost of higher THD and drive losses and a doubling of the differential-mode dv/dt. The final strategy, zero common-mode (ZCM)-SPWM, was modified (MZCM-SPWM) to accommodate IGBT dead-time by delaying the output voltage transitions based on the polarity of the output currents and the direction of the commanded voltage transitions. The MZCM-SPWM method nearly eliminated all CMV pulses while maintaining comparable levels of THD, but produced twice the switching losses compared to PD- and PO- SPWM, and twice the differential-mode <i>dv/dt</i> compared to PD-SPWM.</p>
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13

Zaragoza, Bertomeu Jordi. "Modulation strategies for the neutral-point-clamped converter and control of a wind turbine system." Doctoral thesis, Universitat Politècnica de Catalunya, 2011. http://hdl.handle.net/10803/130900.

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Els convertidors multinivell són topologies de convertidors d’electrònica de potència que poden generar tres o més nivells de voltatge en cadascuna de les fases de sortida. Com a resultat, els voltatges i corrents generats per aquestes topologies presenten una distorsió harmònica baixa. Hi ha diferents configuracions de convertidors multinivell, les quals es basen en connectar dispositius de potència o convertidors en sèrie. El resultat d’aquestes connexions permet obtenir voltatges alts, tant en la part de corrent continu com en la de corrent altern del convertidor. A més, cada dispositiu sols ha de suportar una fracció del voltatge total del bus de corrent continu. Per aquestes raons, els convertidors multinivell són generalment utilitzats en aplicacions d’alta potència. El convertidor de tres nivells amb connexió a punt neutre (neutral-point-clamped) és el més utilitzat. La recerca d’aquesta tesis doctoral està focalitzada en aquesta topologia de convertidor, i el principal objectiu és l’aportació de noves tècniques de modulació. Aquestes tenen en compte diferents aspectes: la velocitat computacional dels algorismes, l’equilibrat de les tensions dels condensadors del bus de contínua, les pèrdues de commutació i les oscil·lacions de baixa freqüència en el punt neutre del convertidor. Totes les estratègies de modulació proposades en aquesta tesis són modulacions d’amplada de polses basades en portadora. En la primera modulació que es presenta, s’injecta un senyal comú (seqüència zero) a totes les moduladores, que es basa en els patrons de la modulació vectorial que utilitza tres vectors dels més propers al de referència (nearest-three-vector modulation). S’estudien i es comparen els resultats d’aquesta modulació amb la seva homòloga, basada en perspectiva vectorial. Una segona proposta és l’anomenada modulació d’amplada de polses de doble senyal (double-signal pulse-width modulation). Aquesta modulació és capaç d’eliminar completament les oscil·lacions de voltatge en el punt neutre del convertidor. No obstant això, es produeix un increment de les pèrdues de commutació en els dispositius de potència i, a més, no hi ha un equilibrat natural de les tensions en els condensadors del bus. Una última estratègia de modulació, anomenada modulació híbrida (hybrid pulse-width modulation), es basa en la combinació de la modulació sinusoïdal (sinusoidal pulse-width modulation) i la de doble senyal. Aquesta presenta una solució de compromís entre reduir les pèrdues de commutació, en detriment d’un augment de l’amplitud de les oscil·lacions de voltatge en el punt neutre. Una segona part d’aquesta tesis es centra en les aplicacions a generació eòlica, ja que els convertidors multinivell estan començant a ser utilitzats en aquest camp. Això es produeix fonamentalment per l’augment continu de les dimensions de les turbines eòliques. En aquesta part de la recerca s’ha considerat la configuració de dos convertidors multinivell connectats a un mateix bus de contínua (back-to-back), tot i que els convertidors han estat estudiats independentment. Inicialment s’ha estudiat el convertidor que va connectat a la xarxa elèctrica i s’ha aplicat l’estratègia de control coneguda com a control orientat a tensió (voltage-oriented control). S’han utilitzat controladors estàndard (proporcional-integral), als quals s’ha afegit un control difús que supervisa i modifica els valors de les constants dels controladors. Aquest supervisor difús millora la dinàmica de la tensió del bus de contínua davant canvis de càrrega quan el convertidor treballa com a rectificador. Per una altra part, s’ha estudiat el control d’una turbina eòlica basada en un generador d’imants permanents. En aquest cas, s’ha aplicat l’estratègia de control coneguda com a control orientat a camp (field-oriented control). S’han avaluat i comparat els avantatges i inconvenients de diferents formes de sintonitzar els controladors.<br>Multilevel converters are power electronic topologies that can generate three or more voltage levels in each output phase. As a result, the voltage and current waveforms generated have lower total harmonic distortion. Multilevel topologies are based on connecting power devices or converters in a series. Consequently, high voltages can be handled on the dc and ac sides of the converter, while each device stands only a fraction of the total dc-link voltage. For these reasons multilevel converters are generally applied to high-power applications. The three-level neutral-point-clamped converter is the most extensively used multilevel topology. This topology is the main focus of research in this dissertation. The main objective is to propose new modulation strategies that are able to meet a compromise solution while considering computational algorithm speed, voltage balance in the dc-link capacitors, switching losses and low frequency voltage oscillations at the neutral point. All the modulation strategies proposed here are based on carrier-based pulsewidth modulation. A new modulation strategy has been implemented using a proper zero-sequence signal injected into the modulation signals. The zero sequence is determined from a space-vector modulation standpoint, particularly the nearest-threevector modulation strategy. The proposed carrier-based technique is compared with its space-vector modulation counterpart. It shows some advantages, such as easier implementation and reduced switching events; however, it still produces oscillations in the neutral-point voltage for some operating conditions. A new modulation strategy able to completely remove such voltage oscillations is also presented. It is called double-signal pulse-width modulation. The main drawback of this strategy is that it increases the switching frequency of the power devices and has no natural capacitor voltage balance. Some balancing strategies are proposed in this dissertation for this specific modulation. Furthermore, a hybrid pulse-width modulation approach is presented which is able to combine sinusoidal pulse-width modulation with doublesignal pulse-width modulation; this represents a compromise solution between switching losses and neutral-point voltage oscillation amplitudes. The second part of this thesis is focused on wind generation applications. Multilevel converters are starting to be used in such a field nowadays, and are expected to be further applied in the near future as the sizes of wind turbines grow. Two back-toback-connected power converters are considered in this application, although they are analyzed independently. First of all, the control of the grid-connected converter is studied. A voltage-oriented control is used with standard proportional-integral controllers. The originality of the method is that a fuzzy supervisor is designed and included in the structure; the fuzzy supervisor is able to modify the proportionalintegral parameters online. It is shown how the control of the total dc-link voltage improves significantly under load changes when the converter is working as a rectifier. On the other hand, a control study is performed on the wind turbine side. The variable speed wind turbine is based on a permanent magnet synchronous generator. A field-oriented control strategy is applied. The controllers are evaluated and compared using different tuning strategies which highlight the advantages and drawbacks of each.
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Mese, Huseyin. "Field Oriented Control Of Permanent Magnet Synchronous Motors Using Three-level Neutral-point-clamped Inverter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614407/index.pdf.

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In this thesis, field oriented control of permanent magnet synchronous motors using three-level neutral-point-clamped inverter is studied. Permanent magnet synchronous motors are used in high performance drive applications. In this study, the permanent magnet synchronous motor is fed by three-level neutral-point-clamped inverter. For three-level neutral-point-clamped inverter different space vector modulation algorithms, which are reported in literature, are analyzed and compared via computer simulations. The voltage balance on dc-link capacitors is also analyzed and a software control method is implemented in conjunction with the space vector PWM modulation, utilized. Nonlinear effects such as dead-time, semiconductor voltage drop and delays in gate drive circuitries also present in neutral-point-clamped inverter. The effects of these nonlinearities are studied and a compensation method for these nonlinear effects is proposed. The theoretical results are supported with computer simulations and verified with experimental results.
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Lee, G. B. "A practical comparison between the three-phase series-stacked and neutral point clamped multilevel converter topologies." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53287.

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Thesis (MScEng)--Stellenbosch University, 2003.<br>ENGLISH ABSTRACT: The versatility of power electronic converters has made them a dominant force in the current electrical and electronic engineering industry. So too industry presents a wider range of applications, forever demanding operation at higher power levels. To meet this need a variety of multilevel converters have evolved. The challenge often lies in the selection of the appropriate topology for a specific application. This thesis presents a practical comparison between the Series-Stacked and Neutral Point Clamped multilevel converter topologies as candidates for Medium Voltage Direct Current and Traction applications. Their configurations, characteristics, switching techniques and practical performances are compared, in order to aid the topology selection process.<br>AFRIKAANSE OPSOMMING: As gevolg van die veelsydigheid van drywings elektroniese omsetters word dit geimplementeer in n toenemende hoeveelheid toepassings met toenemende drywings vlakke in die elektriese en elektroniese industrie. Om aan hierdie behoefte te voorsien het n reeks veelvlak omsetters ontstaan. Die uitdaging hiermee is die keuse van die toepaslike topologie vir n spesifieke doelwit. Hierdie proefskrif vergelyk die Serie Gekoppelde en die Geklemde Neutrale Punt omsetters ten opsigte van konfigirasie, karakteristieke, skakel tegnieke en praktiese werksverrigting om die toepaslikheid te bepaal vir Medium Spanning Gelykstroom en Traksie toepassings.
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Sprenger, Michael [Verfasser]. "Untersuchung des Dreipunkt - Neutral Point Clamped - Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Niederspannungswindkraftanwendungen / Michael Sprenger." München : Verlag Dr. Hut, 2015. http://d-nb.info/1075409365/34.

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Gomez, Palomino Jonathan David. "Design and evaluation of a single phase 5 level full bridge neutral point clamped multi level converter." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18304/.

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This thesis describes multilevel converters (MLC) designed for use with a repurposed electronic vehicle battery (battery 2nd life). MLC is of particular interest due to the low harmonic distortion content and reduced voltage stress in the switching devices. A detailed study of the MLC topologies and modulation techniques is presented. Space vector modulation is analysed and implemented to evaluate the converter. A comprehensive assessment of the MLC is presented using wide bandgap (WBG) devices highlighting the devices’ thermal and high switching frequency features.
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Forrisi, Ivano. "Contribution to renewable systems grid connected : control, stability analysis and reliability." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0345/document.

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Cette thèse a pour but l'analyse d'un système photovoltaïque connecté au réseau électrique en prenant en compte le contrôle, l'étude de la stabilité et la fiabilité. Un onduleur de type 2-Niveau a été comparé avec un onduleur multi-niveaux appelé Neutral Point Clamped. Les avantages et désavantage de chaque topologie ont été analysé en considérant l'efficacité énergétique, l'optimisation de l'injection de l'énergie sur le réseau électrique et la fiabilité du système. Pour le contrôle du courant de sortie de l'onduleur, ont été proposées deux solutions : un contrôle basé sur la théorie de la platitude et un contrôle par passivité. Ces deux différents contrôles sont comparés par rapport à la robustesse, la complexité et le nombre de capteurs utilisés. Il a été montré que les deux contrôles sont capables de gérer la problématique de la résonance du filtre LCL. Pour augmenter l'efficacité de l'algorithme MPPT dans une configuration Distributed-MPPT avec la connexion en série des deux sorties des convertisseurs boost, une nouvelle technique a été proposé pour l'équilibrage des tension d'entrée d'un onduleur NPC. En utilisant un outil appelé TPtool, un étude de la stabilité large signal par "Higher-Order-Singular-Value-Decomposition" a été présenté et comparé avec une méthode basée sur les modèles Takagi-Sugeno pour des systèmes non-linéaires. Finalement, l'onduleur 2-Niveaux est comparé avec deux multi-niveaux différents (NPP et NPC) en termes de disponibilité, en prenant en compte les niveaux de redondance des convertisseurs. Pour analyser la disponibilité, a été considérée la théorie des chaines de Markov et pour l'implémentation, le logiciel GRIF a été utilisé<br>The aim of this PhD thesis is to analyze a PV-grid connected system in terms of control, stability and reliability. A comparison between a classical 2-Level inverter and a multilevel NPC is presented. The advantages and weakness of both the converters are analyzed with respect to the power efficiency, optimization of the energy injection to the grid and reliability of the system. In order to control the inverter output current, two different solutions are proposed: flatness-based control and passivity-based control. These controls are compared in terms of robustness, complexity and number of sensors used. It is shown that both the controls may manage the resonance problems due to a LCL filter. For increasing the efficiency of the MPPT in a configuration Distributed-MPPT with connections in series of the boost converters outputs, a novel technique for the dc voltages balancing of a NPC inverter is proposed. A large stability analysis using "Higher-Order-Singular-Value-Decomposition" is presented and compared with Takagi-Sugeno approach for nonlinear systems. Finally, 2-Level inverter is compared with two multilevel inverters (NPC and NPP) in terms of availability, considering the redundancy levels of the converters. To analyze the systems availability, the Markov chains theory is considered and it is implemented on GRIF
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Sprenger, Michael [Verfasser], Steffen [Akademischer Betreuer] Bernet, and Michael [Akademischer Betreuer] Braun. "Untersuchung des Dreipunkt – Neutral Point Clamped – Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Niederspannungswindkraftanwendungen / Michael Sprenger. Gutachter: Steffen Bernet ; Michael Braun." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/107435012X/34.

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Hu, Xiao Ming. "Development of a System for Testing Grid-connected Doubly Fed Induction Generators with Implementation of a Three-level Neutral-Point-clamped Converter." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29443.

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Consistent international efforts have been made over the past few decades to move the world towards an environmentally sustainable society. Wind energy conversion systems (WECSs) are one of the largest contributors within this movement. Furthermore amongst existing wind turbine power generation technologies, the doubly fed induction generator (DFIG) has been distinctively popular for its lower capital costs especially in higher power applications. In order to study the integration of this type of generator into the grid, a laboratory based DFIG test rig was developed where its complete design process is presented in this dissertation. Mathematical modelling of related system components were thoroughly investigated so as to facilitate controller design based on the internal model control (IMC) methodology. In addition, a complete soft grid synchronisation procedure for the DFIG was investigated. It was found that the application of active damping within the IMC control law resulted in reduced stator current transients during synchronisation. Control voltage excitation for the DFIG rotor circuit was achieved by the implementation of two voltage source converters (VSC’s) connected in a back-to-back configuration via a common DC-link. The rotorside converter (RSC) was responsible for regulating the machine speed whereas the grid-side converter (GSC) was responsible for regulating the DC-link voltage. In addition, these converters provided decoupled and bidirectional power flow control which enabled the DFIG to operate at sub synchronous and super synchronous speeds. A three-level VSC was chosen for the GSC control, where a resource conservative modulation algorithm that eliminates DC-link neutral voltage unbalance was implemented. The DFIG system design was simulated, and the results were verified through experimental tests performed on a 1.5kW wound rotor induction machine (WRIM). A detailed description of the laboratory setup of the DFIG is presented, and various practical limitations are discussed. It was found that the performance of the developed DFIG test rig correlated well with results of the simulations. Stable operation was achieved for various system test conditions, which indicated the system’s robustness to serve as a practical platform for future DFIG related research.
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Jiao, Yang. "High Power High Frequency 3-level NPC Power Conversion System." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/56653.

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The high penetration of renewable energy and the emerging concept of micro-grid system raises challenges to the high power conversion techniques. Multilevel converter plays the key role in such applications and is studied in detail in the dissertation. The topologies and modulation techniques for multilevel converter are categorized at first by a thorough literature survey. The pros and cons for various multilevel topologies and modulation techniques are discussed. The 3-level neutral point clamped (NPC) topology is selected to build a 200kVA, 20 kHz power conversion system. The modularized phase leg building block of the converter is carefully designed to achieve low loss and stress for high frequency and high power operation. The switching characteristics for all the commutation loops of 3-level phase leg are evaluated by double pulse tests. The switching performance is optimized for loss and stress tradeoff. A detailed loss model is built for system loss distribution and loss breakdown calculation. Loss and stress for the phase leg and 3-phase system are quantified at all power factors. The space vector modulation (SVM) for 3-level NPC converter is investigated to achieve loss reduction, neutral voltage balance and noise reduction. The loss model and simulation model provides a quantitative analysis for loss and neutral voltage ripple tradeoff. An improved SVM method is proposed to reduce NP imbalance and switching loss simultaneously. This method also ensures an evenly distributed device loss in each phase leg and gives a constant system efficiency under different power factors. Based on the improved modulation strategy, a new modulation scheme is then proposed with largely reduced conduction loss and switching stress. Moreover, the device loss and stress distribution on a phase leg is more even. This scheme also features on the simplified implementation. The improved switching characteristics for the proposed method are verified by double pulse tests. Also the system loss breakdown and the phase leg loss distribution analysis shows the loss reduction and redistribution result. The harmonic filter for the grid interface converter is designed with LCL topology. A detailed inductor current ripple analysis derives the maximum inductor current ripple and the ripple distribution in a line cycle. The inverter side inductor is designed with the optimum loss and size trade-off. The grid side inductor is designed based on grid code attenuation requirement. Different damping circuits for LCL filter are evaluated in detail. The filter design is verified by both simulation and hardware experiment. The average model for the 3-level NPC converter and its equivalent circuit is derived with the consideration of damping circuit in both ABC and d-q frame. The modeling and control loop design is verified by transfer function measurement on real hardware. The control loops design is also tested and verified on real hardware. The interleaved DC/DC chopper is introduced at last. The different interleaving methods and their current ripple are analyzed in detail with the coupled and non-coupled inductor. An integrated coupled inductor based on 3-dimentional core structure is proposed to achieve high power density and provide both CM and DM impedance for the inductor current and output current.<br>Ph. D.
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Häger, Emil. "Performance Evaluation of Medium-Power Voltage Inverters." Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-118568.

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Power inverters, used to convert DC power to AC, are often used in e.g. solar power applications. However, they tend to be impractically large and expensive; as such, power miniaturization is an active research area. In this thesis, several classes of modern power inverters are evaluated and compared with regards to size, efficiency and output quality in order to identify areas of potential improvement. Methods for estimation of THD, power losses and input ripple are created and verified against a simulation of a five-level neutral-point-clamped inverter with SPWM control. Finally, this design is implemented physically and is found to achieve 94.5% efficiency and 7% THD under low voltage laboratory conditions, while remaining smaller than an average textbook.
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Rankin, Paul Edward. "Modeling and Design of a SiC Zero Common-Mode Voltage Three-Level DC/DC Converter." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93176.

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As wide-bandgap devices continue to experience deeper penetration in commercial applications, there are still a number of factors which make the adoption of such technologies difficult. One of the most notable issues with the application of wide-bandgap technologies is meeting existing noise requirements and regulations. Due to the faster dv/dt and di/dt of SiC devices, more noise is generated in comparison to Si IGBTs. Therefore, in order to fully experience the benefits offered by this new technology, the noise must either be filtered or mitigated by other means. A survey of various DC/DC topologies was conducted in order to find a candidate for a battery interface in a UPS system. A three-level NPC topology was explored for its potential benefit in terms of noise, efficiency, and additional features. This converter topology was modeled, simulated, and a hardware prototype constructed for evaluation within a UPS system, although its uses are not limited to such applications. A UPS system is a good example of an application with strict noise requirements which must be fulfilled according to IEC standards. Based on a newly devised mode of operation, this converter was verified to produce no common-mode voltage under ideal conditions, and was able to provide a 6 dB reduction in common-mode voltage emissions in the UPS prototype. This was done while achieving a peak efficiency in excess of 99% with the ability to provide bidirectional power flow between the UPS and battery backup. The converter was verified to operate at the rated UPS conditions of 20 kW while converting between a total DC bus voltage of 800 V and a nominal battery voltage of 540 V.<br>Master of Science<br>As material advancements allow for the creation of devices with superior electrical characteristics compared to their predecessors, there are still a number of factors which cause these devices to see limited usage in commercial applications. These devices, typically referred to as wide-bandgap devices, include silicon carbide (SiC) transistors. These SiC devices allow for much faster switching speeds, greater efficiencies, and lower system volume compared to their silicon counterparts. However, due to the faster switching of these devices, there is more electromagnetic noise generated. In many applications, this noise must be filtered or otherwise mitigated in order to meet international standards for commercial use. Consequently, new converter topologies and configurations are necessary to provide the most benefit of the new wide-bandgap devices while still meeting the strict noise requirements. A survey of topologies was conducted and the modeling, design, and testing of one topology was performed for use in an uninterruptible power supply (UPS). This converter was able to provide a noticeable reduction in noise compared to standard topologies while still achieving very high efficiency at rated conditions. This converter was also verified to provide power bidirectionally—both when the UPS is charging the battery backup, and when the battery is supplying power to the load.
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Mascarenhas, Manuel Maria Brás Pereira. "Speed control of induction machine based on direct torque control method." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/9957.

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Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores<br>Multi-level converters have been receiving attention in the recent years and have been proposed as the best choice in a wide variety of medium voltage applications. They enable a commutation at substantially reduced voltages and an improved harmonic spectrum without a series connection of devices, which is the main advantage of a multi-level structure. The use of multi-level inverters contributes to the performances amelioration of the induction machine control. In fact, the use of three level inverter (or multilevel inverter) associated with DTC control can contribute to more reducing harmonics and the ripple torque and to have a high level of output voltage. A variation of DTC-SVM with a three level neutral point clamped inverter is proposed and discussed in the literature. The goal of this project is to study, evaluate and compare the DTC and the proposed DTC-SVM technique when applied to induction machines through simulations. The simulations were carried out using MATLAB/ SIMULINK simulation package. Evaluation was made based on the drive performance, which includes dynamic torque and flux responses, feasibility and the complexity of the systems.
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Wilson, Veas Alan Hjalmar [Verfasser], Steffen [Gutachter] Bernet, Mariusz [Gutachter] Malinowski, and Steffen [Akademischer Betreuer] Bernet. "Investigation of Multi-Level Neutral Point Clamped Voltage Source Converters using Isolated Gate Bipolar Transistor Modules / Alan Hjalmar Wilson Veas ; Gutachter: Steffen Bernet, Mariusz Malinowski ; Betreuer: Steffen Bernet." Dresden : Technische Universität Dresden, 2019. http://d-nb.info/1226899463/34.

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26

Ahmadi, Sajjad. "Contribution à l'étude de la tolérance de pannes de convertisseurs multiniveaux en pont en H." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0026.

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La sûreté de fonctionnement de la conversion d’énergie est indispensable pour un grand nombre d’applications, en particulier lors de la mise en œuvre de convertisseurs multiniveaux. Par conséquent, il est important d’assurer la continuité de service de ces convertisseurs, lors de la défaillance d’un des semi-conducteurs. Dans cet objectif, ce mémoire propose un onduleur monophasé multiniveaux à tolérance de pannes, de structure Neutral Point Clamped (NPC) en pont en H, à cinq niveaux. L’algorithme de diagnostic de défaut est basé sur une étude préliminaire des modes de défaillance et repose donc sur analyse des conséquences d’un défaut, basée sur de la logique. Il ne nécessite ni modélisation des composants de l’onduleur, ni calculs complexes. Bien que moins sujettes à défaillance que les interrupteurs actifs, les diodes de clamp peuvent également être en défaut. Dans ce mémoire, l’identification d’une diode de clamp défaillante est également étudiée. De plus, un quantificateur de tension est mis en œuvre lors du diagnostic, afin d’éviter toute fausse détection en raison des erreurs de mesure et des chutes de tension dans le circuit. Suite au diagnostic d’un défaut, des mesures correctives sont appliquées afin de pouvoir assurer la tension et le courant de sortie à leurs valeurs nominales, lors de la défaillance en circuit ouvert d’un interrupteur actif, d’une diode de clamp ou d’une diode de roue libre. Le contenu harmonique des grandeurs électriques de sortie de l’onduleur n’est donc pas affecté par le défaut. La structure proposée pour l’onduleur à tolérance de pannes ne comporte ni contacteur, ni interrupteurs bidirectionnels ; les mesures correctives peuvent donc être appliquées très rapidement. Une sélection de résultats de simulation et de résultats expérimentaux illustre et démontre l’efficacité et la validité de l’approche proposée. Un défaut est détecté en 20 µs et localisé entre 20 et 60 µs après son apparition, selon le semi-conducteur défaillant (interrupteur actif ou diode de clamp)<br>Ensuring service continuity in safety-critical applications is indispensable. In some of these applications, the multilevel inverters play a vital role. Hence, employing a multilevel converter with fault tolerant feature is of great importance. In this regard, a fault tolerant five-level Neutral Point Clamped (NPC) inverter is proposed in this research work. The proposed fault diagnosis algorithm is based on failure mode analysis, which is a logic based approach. The realization of this strategy does not require any component modeling and complicated calculations. Although switches are more fragile than clamping diodes, clamping diodes are also subjected to breakdown. Hence, identification of a defective clamping diode is also studied in this research work. Moreover, for fault detection procedure, a voltage quantifier is proposed to avoid any misdiagnosis arising from measurement errors and voltage drop in the circuit. Following to the fault diagnosis, the proposed fault tolerant strategy aims to restore the rated voltage and current at the inverter terminal in the presence of an open-circuit fault in a switch or in a clamping or anti-parallel diode. Compared with healthy operation, harmonic content of the terminal voltage and current is not increased. The proposed fault tolerant structure does not include any contactor or bidirectional switch, which allows fast triggering of fault tolerant operation. The simulation and experimental results are presented to validate the effectiveness of the proposed approaches. A fault is detected in 20 µs and localized between 20 and 60 µs after occurrence, depending on the faulty semiconductor (switch or clamping diode)
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Henn, Gustavo Alves de Lima. "TÃcnica de ModulaÃÃo Aplicada Ãs Estruturas de Inversores MultinÃveis com Neutro Grampeado e Capacitor Flutuante Para ReduÃÃo de Perdas e DistorÃÃo HarmÃnica." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8095.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior<br>Visando superar os desafios inerentes à conversÃo de energia elÃtrica em sistemas de alta potÃncia, minimizando as perdas e melhorando a qualidade da energia processada, este tra-balho tem por objetivo analisar e implementar uma tÃcnica de modulaÃÃo para ser aplicada nas duas topologias de inversores multinÃveis mais disseminadas - com neutro grampeado (NPC), e com capacitor flutuante (FC) - a fim de reduzir os esforÃos nos semicondutores, bem como melhorar o Ãndice de distorÃÃo harmÃnica da tensÃo de saÃda. Ao longo do trabalho foi evidenciada a necessidade da digitalizaÃÃo da tÃcnica proposta, visto que o desenvolvimento analÃgico da mesma acarretaria em um circuito complexo e de baixa confiabilidade. Dessa forma, escolheu-se como plataforma digital um FPGA, devido à sua facilidade de programa-ÃÃo e reconfiguraÃÃo, alÃm da alta velocidade e quantidade de pinos de entrada e saÃda. AlÃm da tÃcnica proposta, foram tambÃm desenvolvidas outras modulaÃÃes para fins de compara-ÃÃo, apresentando os padrÃes de chaveamento para cada uma delas, bem como o comporta-mento da corrente atravÃs dos semicondutores em cada perÃodo de chaveamento. Foi tambÃm realizada a anÃlise teÃrica das topologias e suas respectivas etapas de operaÃÃo, caracterÃsticas e levantamento das equaÃÃes que ditam a anÃlise das perdas para as diferentes situaÃÃes de tÃcnicas aplicadas a cada uma das estruturas. O desenvolvimento digital das tÃcnicas mostrou-se correta atravÃs da anÃlise das formas-de-onda colhidas por meio de um circuito digital-analÃgico. AlÃm disso, a comparaÃÃo da aplicaÃÃo dessas modulaÃÃes em inversores a trÃs nÃveis NPC e FC de 6 kW mostrou-se favorÃvel à tÃcnica proposta em termos de eficiÃncia e reduÃÃo da distorÃÃo harmÃnica em ambas as topologias, comprovando sua utilidade em con-versores multinÃveis de alta potÃncia. Por fim, foi apresentado o desenvolvimento da tÃcnica proposta em inversores com mais de trÃs nÃveis, onde se pode comprovar sua eficiente aplica-ÃÃo para tais fins, bem como sua expansibilidade para inversores de n nÃveis.<br>In order to overcome the challenge of processing electric energy in high power systems with minimal losses and high energy quality, this work presents the implementation and anal-ysis of a modulation technique applicable on both most well-known multilevel inverter struc-tures - neutral point-clamped (NPC), and flying capacitors (FC) - to reduce the stresses across the semiconductors devices, and to improve the total harmonic distortion of the output volt-age. Throughout the work, the necessity to digitalize the proposed technique has been evi-denced due to the high complexity and low reliability inherent to the analogical approach. Thus, the digital controller FPGA has been chosen, as it is easy to program and reconfigure, works at high speed, and has a lot of input and output pins. Additionally, other modulation techniques were also implemented to compare their performance with the proposed one, pre-senting the switching patterns and the behavior of the electrical currents through the semicon-ductors for each modulation. A theoretical analysis was also performed for both topologies and their respective operation principle, characteristics, and equations used on the losses anal-ysis for the different combinations of modulation applied to each structure. Finally, the digital development of the various techniques has proved to be correct by observing the waveforms obtained through the digital/analogical circuit. Besides, the comparison of the modulation techniques on 6 kW NPC and FC three-level prototype inverters proved to be favorable to the proposed technique in terms of efficiency and total harmonic distortion reduction on both topologies, confirming its usefulness on high power multilevel converters. At last, it was pre-sented the application of the proposed modulation technique to inverters with more than three levels, where it was observed its eligibility for n-levels topologies.
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Silva, Tiago Lemes da. "Estudo do inversor monofásico NPC T-Type de cinco níveis para processamento de energia solar fotovoltaica." Universidade do Estado de Santa Catarina, 2014. http://tede.udesc.br/handle/handle/2080.

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Made available in DSpace on 2016-12-12T20:27:38Z (GMT). No. of bitstreams: 1 Tiago Lemes.pdf: 2229669 bytes, checksum: 9b9cd44356c6d0002fccf67fe418f52b (MD5) Previous issue date: 2014-09-26<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>The main subject of this work is the study of a 5 levels T-Type NPC inverter topology, which is applied in photovoltaic energy processing for power generation. The grid power injection is done controlling converter current, which is injected into grid. This work presents equations, component-designs and their validation, which are necessary for the Inverter s power structure implementation. Also inverter modeling and design of implemented controllers are described. Through this study, it was possible to build a 3 kW prototype, which besides the current control, has a system to balance the differential voltage of bus capacitors. Through the prototype, experimental results were acquired.<br>O objeto de estudo deste trabalho é a topologia inversora NPC T-Type 5 níveis, aplicada no processamento da energia fotovoltaica, sendo o principal objetivo a geração de energia elétrica por meio do controle da corrente aplicada à rede. Este trabalho apresenta o equacionamento, projeto dos componentes e sua validação, que fazem parte da estrutura de potência do inversor, bem como a sua modelagem e projeto dos controladores implementados. Por intermédio deste estudo foi possível construir um protótipo com potência nominal de 3 kW, que além do controle da corrente, apresenta uma malha de equilíbrio da tensão diferencial do barramento. Mediante construção desse protótipo, foram extraídos os resultados experimentais.
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29

Forrisi, Ivano. "Contribution to renewable systems grid connected : control, stability analysis and reliability." Electronic Thesis or Diss., Université de Lorraine, 2016. http://www.theses.fr/2016LORR0345.

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Cette thèse a pour but l'analyse d'un système photovoltaïque connecté au réseau électrique en prenant en compte le contrôle, l'étude de la stabilité et la fiabilité. Un onduleur de type 2-Niveau a été comparé avec un onduleur multi-niveaux appelé Neutral Point Clamped. Les avantages et désavantage de chaque topologie ont été analysé en considérant l'efficacité énergétique, l'optimisation de l'injection de l'énergie sur le réseau électrique et la fiabilité du système. Pour le contrôle du courant de sortie de l'onduleur, ont été proposées deux solutions : un contrôle basé sur la théorie de la platitude et un contrôle par passivité. Ces deux différents contrôles sont comparés par rapport à la robustesse, la complexité et le nombre de capteurs utilisés. Il a été montré que les deux contrôles sont capables de gérer la problématique de la résonance du filtre LCL. Pour augmenter l'efficacité de l'algorithme MPPT dans une configuration Distributed-MPPT avec la connexion en série des deux sorties des convertisseurs boost, une nouvelle technique a été proposé pour l'équilibrage des tension d'entrée d'un onduleur NPC. En utilisant un outil appelé TPtool, un étude de la stabilité large signal par "Higher-Order-Singular-Value-Decomposition" a été présenté et comparé avec une méthode basée sur les modèles Takagi-Sugeno pour des systèmes non-linéaires. Finalement, l'onduleur 2-Niveaux est comparé avec deux multi-niveaux différents (NPP et NPC) en termes de disponibilité, en prenant en compte les niveaux de redondance des convertisseurs. Pour analyser la disponibilité, a été considérée la théorie des chaines de Markov et pour l'implémentation, le logiciel GRIF a été utilisé<br>The aim of this PhD thesis is to analyze a PV-grid connected system in terms of control, stability and reliability. A comparison between a classical 2-Level inverter and a multilevel NPC is presented. The advantages and weakness of both the converters are analyzed with respect to the power efficiency, optimization of the energy injection to the grid and reliability of the system. In order to control the inverter output current, two different solutions are proposed: flatness-based control and passivity-based control. These controls are compared in terms of robustness, complexity and number of sensors used. It is shown that both the controls may manage the resonance problems due to a LCL filter. For increasing the efficiency of the MPPT in a configuration Distributed-MPPT with connections in series of the boost converters outputs, a novel technique for the dc voltages balancing of a NPC inverter is proposed. A large stability analysis using "Higher-Order-Singular-Value-Decomposition" is presented and compared with Takagi-Sugeno approach for nonlinear systems. Finally, 2-Level inverter is compared with two multilevel inverters (NPC and NPP) in terms of availability, considering the redundancy levels of the converters. To analyze the systems availability, the Markov chains theory is considered and it is implemented on GRIF
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30

PORRU, MARIO. "Management and control of energy storage systems for stationary and automotive applications." Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266607.

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This PhD dissertation has presented a number of scenarios in which Energy Storage Systems (ESSs) can be usefully employed for increasing energy system performances. Particularly, after introducing the State-of-the-Art of ESS technologies (Chapter 1), reference has been made to some stationary and automotive applications. Stationary applications have regarded Renewable Energy Sources (RESs) exploitation issues and EV integration within micro-grids (Chapter 2). It has been shown that ESSs are particularly useful in compensating for RES forecasting errors, whereas they are much less effective as energy buffers. In addition, Vehicle to Grid (V2G) has also been revealed as an alternative and viable solution for increasing RES penetration level and micro-grid autonomy, even in presence of small EV fleets. The promising results obtained in the energy management of power systems by means of the use of V2G and G2V paradigm have suggested the integration of Electric Vehicles (EVs) into the power system. This requires that EV energy storage systems should satisfy both electric propulsion and power system requirements. With this aim, the design and management of a novel Hybrid Energy Storage System (HESS) for EVs has been considered (Chapter 3). Particularly, the proposed configuration allows the reduction of the peak current delivered by EV batteries, thus preserving their rated performances and increasing their lifetime. This goal has been achieved by means of a suitable management of the energy flows provided by the HESS, leading to a good exploitation of the proposed topology. The effectiveness of the proposed solutions has been verified through several extensive simulation studies, which have been carried out in the Matlab environment. In conclusion, it can be stated that all cases have revealed the need of carefully sizing and managing ESSs in order to achieve optimal results. In this context, it is worth noting that the employment of large ESS easily leads to enhanced performances but also to significant increased costs. This drawback cannot be sustained, especially in automotive applications, in which EV competitiveness is strictly related to a decrease of ESS size, weight and costs. On the other hand, small ESSs do not generally guarantee the same performances but they can be quite similar if optimal management and control strategies are employed. These last thus will cover a fundamental role in making ESS more widespread, enabling an optimal trade-off among increased performances, costs, management and control issues.
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31

Gaptia, Maï Moussa Lawan. "Gestion optimale d'énergie électrique à partir des sources d'énergies renouvelables dédiées aux sites isolés Power control for decentralized energy production system based on the renewable energies — using battery to compensate the wind/load/PV power fluctuations Three level Neutral-Point-Clamped Inverter Control Strategy using SVPWM for Multi-Source System Applications Wind turbine and Batteries with Variable Speed Diesel Generator for Micro-grid Applications." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMLH28.

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Les travaux de thèse s’inscrivent dans les problématiques des travaux de recherche de l’équipe thématique : Maitrise des Energies Renouvelables et systèmes de Stockage (MERS) du laboratoire GREAH-EA3220. Ils englobent le dimensionnement des éléments constitutifs du système et la gestion optimale de l’énergie électrique pour un système hybride (Diesel à vitesse variable, Eolien, PV et Batteries) dédié aux sites isolés. Les sources de production d'énergie alimentent des charges par le biais de convertisseurs multi-niveaux d’électronique de puissance. Le groupe électrogène comportant un moteur diesel à vitesse variable est considéré comme la principale source d’énergie utilisée pour contrôler la tension continue du point de couplage. Ce type de groupe électrogène est choisi pour optimiser la consommation du carburant. Il est sollicité pour délivrer une puissance électrique compatible avec le régime du moteur qui supporte mal les variations fréquentes et rapides. Les sources d’énergie renouvelables dont on cherche à augmenter la part d’énergie pour satisfaire la demande sont pilotées de manière à extraire instantanément le maximum de puissances disponible par les ressources (ensoleillement, vent). Celles-ci imposent ainsi leurs dynamiques et leurs intermittences au point de couplage. Le pack des batteries sert à compenser les fluctuations rapides de l’énergie provenant des sources d’énergie renouvelables par rapport à une évolution plus lente prise en charge par le groupe électrogène. La gestion des interactions au sein du système électrique hybride résultant est assurée au moyen de convertisseurs statiques multi-niveaux (AC / DC, DC / DC et DC / AC). Une approche de gestion d’énergie électrique fondée sur la répartition fréquentielle des perturbations induites au point de couplage par les sources renouvelables. Une plateforme expérimentale à échelle réduite (1/22) a été développée pour valider expérimentalement les approches théoriques et les simulations. Les résultats de simulations obtenus dans l’environnement logiciel Matlab/Simulink/SimPowerSystems et ceux issus du dispositif expérimental réalisé et piloté par dSPACE-1104 prouvent l’adéquation des méthodes de contrôle proposées<br>The thesis works are part of the research work of the thematic team: Mastery of Renewable Energies and Storage Systems (MERS) of the GREAH-EA3220 laboratory. They include the dimensioning of the constituent elements of the system and the optimal management of electrical energy for a hybrid system (Variable speed Diesel, Wind, PV and Batteries) dedicated to isolated sites. Power sources supply loads through multi-level converters of power electronics. The generator set with a variable speed diesel engine is considered to be the main source of energy used to control the DC voltage at the coupling point. This type of generator is chosen to optimize fuel consumption. It is used to deliver an electrical power compatible with the engine speed which does not tolerate frequent and rapid variations. Renewable energy sources whose share of energy is sought to meet demand are managed so as to instantly extract the maximum power available from resources (sunshine, wind). These thus impose their dynamics and their intermittences at the coupling point. The battery pack is used to compensate for rapid fluctuations in energy from renewable energy sources compared to a slower evolution supported by the generator. Interactions within the resulting hybrid electrical system are managed by means of multi-level static converters (AC / DC, DC / DC and DC / AC). An electrical energy management approach based on the frequency distribution of disturbances induced at the coupling point by renewable sources. An experimental platform on a reduced scale (1/22) has been developed to experimentally validate theoretical approaches and simulations. The results of simulations obtained in the Matlab / Simulink / SimPowerSystems software environment and those from the experimental device produced and piloted by dSPACE-1104 prove the adequacy of the proposed control methods
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32

Elamalayil, Soman Deepak. "Multilevel Power Converters with Smart Control for Wave Energy Conversion." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332730.

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The main focus of this thesis is on the power electronic converter system challenges associated with the grid integration of variable-renewable-energy (VRE) sources like wave, marine current, tidal, wind, solar etc. Wave energy conversion with grid integration is used as the key reference, considering its high energy potential to support the future clean energy requirements and due the availability of a test facility at Uppsala University. The emphasis is on the DC-link power conditioning and grid coupling of direct driven wave energy converters (DDWECs). The DDWEC reflects the random nature of its input energy to its output voltage wave shape. Thereby, it demands for intelligent power conversion techniques to facilitate the grid connection. One option is to improve and adapt an already existing, simple and reliable multilevel power converter technology, using smart control strategies. The proposed WECs to grid interconnection system consists of uncontrolled three-phase rectifiers, three-level boost converter(TLBC) or three-level buck-boost converter (TLBBC) and a three-level neutral point clamped (TLNPC) inverter. A new method for pulse delay control for the active balancing of DC-link capacitor voltages by using TLBC/TLBBC is presented. Duty-ratio and pulse delay control methods are combined for obtaining better voltage regulation at the DC-link and for achieving higher controllability range. The classic voltage balancing problem of the NPC inverter input, is solved efficiently using the above technique. A synchronous current compensator is used for the NPC inverter based grid coupling. Various results from both simulation and hardware testing show that the required power conditioning and power flow control can be obtained from the proposed multilevel multistage converter system. The entire control strategies are implemented in Xilinx Virtex 5 FPGA, inside National Instruments’ CompactRIO system using LabVIEW. A contour based dead-time harmonic analysis method for TLNPC and the possibilities of having various interconnection strategies of WEC-rectifier units to complement the power converter efforts for stabilizing the DC-link, are also presented. An advanced future AC2AC direct power converter system based on Modular multilevel converter (MMC) structure developed at Siemens AG is presented briefly to demonstrate the future trends in this area.
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33

Krug, Dietmar. "Vergleichende Untersuchungen von Mehrpunkt-Schaltungstopologien mit zentralem Gleichspannungszwischenkreis für Mittelspannungsanwendungen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-216245.

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Die vorliegende Arbeit befasst sich mit einem detaillierten Vergleich von Mehrpunkt-Schaltungstopologien mit zentralem Gleichspannungszwischenkreis für den Einsatz in Mittelspannungsanwendungen. Im Rahmen dieser Untersuchungen wird die 3-Level Neutral Point Clamped Spannungswechselrichter Schaltungstopologie (3L-NPC VSC) sowohl mit Multilevel Flying Capacitor (FLC) als auch mit Multilevel Stacked Multicell (SMC) Schaltungstopologien verglichen, wobei unter Verwendung von aktuell verfügbaren IGBT-Modulen Stromrichterausgangsspannungen von 2.3 kV, 4.16 kV und 6.6 kV betrachtet werden. Neben der grundlegenden Funktionsweise wird die Auslegung der aktiven Leistungshalbleiter und der passiven Energiespeicher (Zwischenkreiskondensatoren, Flying Capacitors) für die untersuchten Stromrichtertopologien dargestellt. Unter Berücksichtigung verschiedener Modulationsverfahren und Schaltfrequenzen werden Kennwerte für den Oberschwingungsgehalt in der Ausgangsspannung und dem Ausgangsstrom vergleichend evaluiert. Die installierte Schalterleistungen, die Halbleiterausnutzungsfaktoren, die Stromrichterverlustleistungen sowie die Verlustleistungsverteilungen werden für die betrachteten Stromrichtertopologien detailliert gegenübergestellt und bewertet<br>The thesis deals with a detailed comparison of voltage source converter topologies with a central dc-link energy storage device for medium voltage applications. The Three-Level Neutral Point Clamped Voltage Source Converter (3L-NPC VSC) is compared with multilevel Flying Capacitor (FLC) and Stacked Multicell (SMC) Voltage Source Converters (VSC) for output voltages of 2.3 kV, 4.16 kV and 6.6 kV by using state-of-the-art 6.5 kV, 3.3 kV, 4.5 kV and 1.7kV IGBTs. The fundamental functionality of the investigated converter topologies as well as the design of the power semiconductors and of the energy storage devices (Flying Capacitors and Dc-Link capacitors) is described. The installed switch power, converter losses, the semiconductor loss distribution, modulation strategies and the harmonic spectra are compared in detail
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34

Ngo, Van Quang Binh. "Algorithmes de conception de lois de commande prédictives pour les systèmes de production d’énergie." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC031/document.

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Cette thèse vise à élaborer de nouvelles stratégies de commande basées sur la commande prédictive pour le système de génération d’énergie éolienne. La topologie des systèmes de production éolienne basées sur le Générateur Asynchrone à Double Alimentation (GADA) qui convient à des plateformes de génération dans la gamme de puissance de 1.5 à 6 MW est abordée. Du point de vue technologique, le convertisseur à trois niveaux et clampé par le neutre (3L-NPC) est considéré comme une bonne solution pour une puissance élevée en raison de ses avantages: capacité à réduire la distorsion harmonique de la tension de sortie et du courant, et augmentation de la capacité du convertisseur grâce à une tension réduite appliquée à chaque semi-conducteur de puissance. Une description détaillée de la commande prédictive à ensemble de commande fini (FCS-MPC) avec un horizon de prédiction de deux pas est présentée pour deux boucles de régulation: celle liée au convertisseur connecté au réseau et celle du convertisseur connecté au GADA. Le principe de la commande repose sur l’utilisation d’un modèle de prédiction permettant de prédire le comportement du système pour chaque état de commutation du convertisseur. La minimisation d’une fonction de coût appropriée prédéfinie permet d’obtenir la commutation optimale à appliquer au convertisseur. La thèse étudie premièrement les problèmes liées à la compensation du temps de calcul de la commande et au choix et aux pondérations de la fonction de coût. Ensuite, le problème de stabilité de la commande FCS-MPC est abordé en considérant une fonction de Lyapunov dans la minimisation de la fonction de coût. Finalement, une étude sur la compensation des effets des temps morts du convertisseur est présentée<br>This thesis aims to elaborate new control strategies based on Model Predictive control for wind energy generation system. We addressed the topology of doubly fed induction generator (DFIG) based wind generation systems which is suitable for generation platform power in the range in 1.5-6 MW. Furthermore, from the technological point of view, the three-level neutral-point clamped (3L-NPC) inverter configuration is considered a good solution for high power due to its advantages: capability to reduce the harmonic distortion of the output voltage and current, and increase the capacity of the converter thanks to a decreased voltage applied to each power semiconductor.In this thesis, we presented a detailed description of finite control set model predictive control (FCS-MPC) with two step horizon for two control schemes: grid and DFIG connected 3L-NPC inverter. The principle of the proposed control scheme is to use system model to predict the behaviour of the system for every switching states of the inverter. Then, the optimal switching state that minimizes an appropriate predefined cost function is selected and applied directly to the inverter.The study of issues such as delay compensation, computational burden and selection of weighting factor are also addressed in this thesis. In addition, the stability problem of FCS-MPC is solved by considering the control Lyapunov function in the design procedure. The latter study is focused on the compensation of dead-time effect of power converter
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35

YANG, HAN-SHENG, and 楊翰昇. "Simulation and FPGA Implementation of SPWM Based Multilevel Active Neutral-Point Clamped Inverters." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/cgqvz9.

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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>106<br>This thesis investigates the circuit topology of a three-level active neutral-point clamped(3L-ANPC) inverter at first. Five schemes of modulation technology for the 3L-ANPC: the traditional two kinds of modulation(PWM-1, PWM-2), DF-PWM, ALD-PWM and ADF-PWM, are explored, the loss of distribution when use these five technologies in the 3L-ANPC are analyzed. Then this thesis investigates four different topologies of five-level circuit: 8S-5L-ANPC, 5L-T-type-ANPC, 7S-5L-ANPC and 6S-5L-ANPC. Two modulation methods applicable to these four circuit topologies are detailed analyzed, and how to achieve capacitor voltage balance control is explained. The simulation results from MATLAB/Simulink are used to validate the theoretical analysis. Finally, the ALTERA Quartus II is used for design the switch excitation signals, then the code is downloaded to a FPGA board (DE2-115). A three-level ANPC and a five-level ANPC with MOSFET and IGBT as the switches are implemented and the experimental results verify the feasibility.
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36

LIN, JHONG-CYUAN, and 林中全. "Analysis of Open-Circuit Switch Faults and Fault Diagnosis for Active Neutral-Point-Clamped Inverters." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/k794fx.

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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>106<br>This thesis investigates the fault behavior and analysis for open-switch damages in active neutral point clamped inverters.This thesis analyzes the influence of the terminal voltage on the four working areas of the inverter operation first, and summarizes the fault analysis results.Then the Active neutral point clamped inverter is modeled in MATLAB/Simulink to analyze the performance of this inverter.This thesis analyses the working situation of the switching devices under the open-circuit fault, studies the specific fault characteristics and typical waveforms in detail.Finally, the simulation results illustrate that open switch faults diagnosis system can get correct and fast effect for identification.
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37

Wu, Meng Chen, and 吳孟臻. "Development of the Three-phase Four-Wire Active Power Filter with the Neutral Point Clamped Converter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/68094596919663698889.

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38

Sprenger, Michael. "Untersuchung des Dreipunkt – Neutral Point Clamped – Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Niederspannungswindkraftanwendungen." Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A28801.

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Das Ziel der Arbeit war die Untersuchung eines neuartigen Phasenbausteins mit der Topologie des Dreipunkt – Neutral Point Clamped – Stromrichters mit Spannungszwischenkreis (3L-NPC-VSC) für Windkraftanwendungen. Wichtige Anforderungen an den Phasenbaustein und daraus resultierende Herausforderungen, sowie Lösungen für ausgewählte Teilprobleme werden präsentiert. Um die Vorteile des 3L-NPC-VSC für Hersteller von Windkraftanlagen zugänglich zu machen, ist es sinnvoll, einen neuartigen Phasenbaustein zu entwickeln. Der Phasenbaustein soll einfach in Systeme zu integrieren sein, in denen gegenwärtig Zweipunktstromrichter (2L-VSC) zum Einsatz kommen. Da sich Modulation, Zwischenkreisbalancierung und Kurzschlussschutz vom 2L-VSC unterscheiden, soll der Phasenbaustein diese Herausforderungen eigenständig bewältigen. Die Arbeit beschreibt die Konzeption eines solchen Phasenbausteins und behandelt insbesondere die Modulation, die Zwischenkreisbalancierung und den Kurzschlussschutz des 3L-NPC-VSC. Ein Vergleich verschiedener Modulationsverfahren wurde durchgeführt und die am besten geeigneten Verfahren für die Implementation in den Phasenbaustein ausgewählt. Eine Anforderung war, dass dieser Signale einer übergeordneten Regelung verarbeiten kann, welche für einen 2L-VSC berechnet wurden. Ein Überblick der Zwischenkreisbalancierungsverfahren zeigte, dass nahezu alle den Nachteil einer zusätzlich benötigten Strommessung haben. Die Untersuchung einer neuen an der Professur Leistungselektronik der TU Dresden entwickelten Methode ohne den Bedarf der Strommessung zeigte, dass diese anwendbar ist. Der Algorithmus wurde simuliert, implementiert und experimentell getestet und zeigte gute Resultate. Die Aufgabe eines komplett unabhängigen Kurzschlussschutzes war die schwierigste. Alle möglichen Fehler innerhalb eines Moduls wurden analysiert und kategorisiert. Einige Fehlertypen können innerhalb einer Phase behandelt werden. Entsprechende Algorithmen wurden entwickelt und getestet. Allerdings gibt es Fehlertypen, die nicht durch die Steuerung einer einzelnen Phase behandelt werden können. Eine schnelle Kommunikation zwischen den drei Phasen des Konverters wäre notwendig. Alternativ könnte eine übergeordnete Steuerung diese Fehler behandeln. Zum Schluss wurde ein Demonstrator des Phasenbausteins aufgebaut und experimentell untersucht. Einige Messergebnisse werden gezeigt, um die Funktion zu verifizieren.:1 Einleitung 1.1 Motivation 1.2 Zielstellung 1.3 Inhalt der Arbeit 2 Stromrichter für Windkraftanlagen 2.1 Stand der Technik 2.1.1 Zweipunktstromrichter mit Spannungszwischenkreis 2.1.2 Dreipunkt-Neutral-Point-Clamped-Stromrichter mit Spannungszwischenkreis 2.1.3 Kommerziell verfügbare Stromrichter für WKA 2.2 Vollumrichterlösung mit erhöhter Ausgangsspannung 2.2.1 Motivation und Anforderungen 2.2.2 Vereinfachter Vergleich von Zwei- und Dreipunktstromrichtern 2.3 Herausforderungen bei der Realisierung des 3L-NPC-VSC 3 Struktur und Funktion eines neuartigen 3L-NPC-Phasenbausteins 3.1 Struktur und Schnittstellen 3.1.1 Stand der Technik für 3L-NPC Phasenbausteine 3.1.2 Neuartiger 3L-NPC-VSC-Phasenbaustein 3.2 Realisierung 3.2.1 Anforderungen 3.2.2 Technische Realisierung 3.3 Experimentelle Verifikation 3.3.1 Versuchsstand 3.3.2 Messergebnisse 4 Modulation und Zwischenkreisbalancierung eines 3L-NPC-VSC 4.1 Modulationsarten im Überblick 4.1.1 Trägerbasierte Modulation für den 3L-NPC-VSC 4.2 Ausgewählte Modulation für den neuartigen Phasenbaustein 4.2.1 Zweipunktraumzeigermodulation in einem Trägerband 2L-SVM 4.2.2 Dreipunktraumzeigermodulation 3L-SVM 4.3 Stand der Technik bei Zwischenkreisbalancierungsverfahren 4.4 Die direkte Totzeitregelung zur Zwischenkreisbalancierung 4.4.1 Theoretische Grundlagen 4.4.2 Simulative Verifikation der direkten Totzeitregelung 4.4.3 Experimentelle Verifikation der DDTC 5 Kurzschlussschutz eines 3L-NPC-VSC-Phasenbausteins 5.1 Versuchsstand I5.2 Kurzschlussfehler einer 3L-NPC-VSC-Phase 5.2.1 Kategorisierung der Kurzschlüsse 5.2.2 Untersuchte Bauteilfehler innerhalb einer 3L-NPC-VSC-Phase 5.3 Kurzschlussbehandlungsmethoden 5.3.1 Stand der Technik 5.3.2 Schutzmaßnahmen für 3L-NPC-VSC 5.4 Analyse von Kurzschlüssen und Ableitung von Behandlungsmaßnahmen 5.4.1 Fehler eines äußeren IGBTs 5.4.2 Fehler eines inneren IGBTs 5.4.3 Fehler einer Clampdiode 5.5 Maßnahmen zur sicheren Behandlung von Kurzschlüssen in 3L-NPC-VSC 6 Zusammenfassung
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Lopes, Pedro Manuel Antunes Faria. "Diagnóstico de Avarias e Tolerância a Falhas em Filtros Activos de Potência de 3 e 4 Fios, Baseados na Topologia Multinível NPC." Master's thesis, 2012. http://hdl.handle.net/10316/99531.

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Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.<br>Nos últimos anos, o mundo tem assistido a um grande desenvolvimento tecnológico marcado sobretudo pela proliferação de sistemas informáticos e de accionamentos eléctricos. No entanto, a utilização massiva deste tipo de cargas, ditas não-lineares, acarreta grandes problemas no que toca à qualidade da energia eléctrica, criando uma elevada poluição harmónica. Na tentativa de minimizar estes efeitos nocivos surgiram os filtros activos de potência, tradicionalmente compostos por um conversor de 2 níveis. Porém, devido aos recentes desenvolvimentos nas topologias multinível, estas começaram a integrar os sistemas de filtragem, conferindo-lhes um melhor desempenho. Contudo, uma vez que é usado um maior número de semicondutores, a probabilidade de ocorrência de uma falha de circuito aberto ou de curto-circuito num deles aumenta consideravelmente. Deste modo, surge a necessidade de desenvolver estratégias que permitam identificar estas avarias e actuar imediatamente de forma a que o sistema possa permanecer em funcionamento. No seguimento desta problemática, na presente dissertação irão ser propostos métodos de diagnóstico e de tolerância a falhas para filtros activos de potência paralelos de 3 e 4 fios, baseados num conversor NPC de 3 níveis. A validade das técnicas apresentadas irá ser comprovada através de simulações computacionais e de ensaios experimentais.<br>In the past few years, the world has witnessed a great technological development, where the computer systems and the electric drives play an important role. However, the massive widespread of this so called non-linear loads brings many problems regarding the electric power quality, creating a high harmonic pollution. In order to mitigate this harmful effect, the active power filters have appeared, traditionally composed by a 2 level converter. Nevertheless, due to recent development of multilevel topologies, they are becoming to integrate these filtering systems, improving their performance. However, since it is needed a greater number of switching devices, the probability of an open circuit or a short-circuit failure in one of them is significantly higher. Thus, it is important to develop strategies to identify these faults and act immediately in order to keep the system operational. Then, in this dissertation will be proposed fault diagnosis and fault tolerance methods for 3 and 4 wire shunt active power filters, based on a 3 level NPC converter. The effectiveness of these techniques will be demonstrated by simulation and experimental results.
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40

Wang, Yao Bang, and 王耀邦. "The Neutral-Point Voltage Control of Neutral Point Clamped Converters." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/32479767039129504408.

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41

Chen, Der-Jan, and 陳德政. "Study and Implementation of Neutral Point Diode Clamped Power Converter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/77506145897757144144.

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碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>89<br>The widespread use of solid-state converters have resulted in many power quality issues such as harmonic distortion in the line current, low power factor, low efficiency and voltage flicker, etc. In this thesis, a multilevel pulse width modulation (PWM) converter which is suitable for high voltage / high power applications is proposed. With the advantages of low voltage harmonic distortion, low EMI, low voltage rating of the switching devices, power reversible, easy implementation and reduction in size and weight, the proposed neutral point diode clamped power converter was applied to the following applications: power factor correction, active power filter, voltage regulator and on line uninterruptible power supply. The simulation (based on Matlab/Simulink) and experimental results are presented. The author employed the TMS320C240 EVM board with some expanded peripheral circuit to realize the modular control circuit. The results revealed that the adopted multilevel technology has the characteristics of high power factor, and high efficiency, and can be used in the medium voltage and high power applications.
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42

Lan, Chien-Wei, and 藍健瑋. "Three-level Neutral-Point-Clamped Rectifier under Unbalanced Grid Source." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/a8v874.

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碩士<br>國立臺灣科技大學<br>電機工程系<br>105<br>This thesis proposed a modified unity power factor controller to improve the line current unbalance factor for a three-level Neutral Point Clamped (NPC) rectifier under unbalanced grid source. The delay signal cancellation phase-sequence separation method is adapted to the unity power factor controller to obtain the desired positive-sequence component from the unbalanced grid source as the reference signals. This thesis also investigate the dc bus voltage ripple and finds that the amplitude, frequency, and phase are significantly affected by the unbalanced grid source. The relationship between the ripple and the unbalanced conditions could be used for compensation and improving the ac line current conditions. A MATLAB-based simulation system was built to evaluate the performance of the proposed converter. An experimental test bench, which employs a digital signal processor (TMS320F28069), with 750VDC/ 2k W rating was established for measurement. Finally, both simulation and experimental results demonstrate the validity of the proposed scheme.
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43

Hung, Tsung-Liang, and 洪宗良. "Study and Implementation of Neutral Point AC Switch Clamped Power Converter." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/41714141138029908433.

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碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>90<br>Power electronic products have been widely used in the industry. But these products produce the serious power pollution. The power pollution problems results in low power quality and low efficiency. The power quality include the cases of under-voltage, over-voltage, outage, surge, dip, voltage sag, voltage swell, harmonics, electromagnetic inference (EMI), flicker, voltage frequency variation and unbalance. In the recent market products, we can not find a perfect and low cost product to solve above mentioned problems for power pollution. Large current harmonics, low power factor and low efficiency are the main drawbacks of diode or phase-controlled rectifier. In this thesis, a multilevel pulse width modulation (PWM) converter used in the medium voltage and high power applications is proposed to replace the conventional power converter. With the advantages of low harmonic distortion, low EMI, low voltage rating of the switching devices, power reversible and reduction in size and weight, the neutral-point switch-clamped converter is proposed. The proposed neutral-point-clamped converter can be operated as an active power filter, power factor corrector, on line uninterruptible power supply and voltage regulator. To verify the proposed operation scheme, performance characteristics are given by the computer simulation and experimental results.
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44

Tsai, Kun-Che, and 蔡昆哲. "FPGA Implementation of Space Vector Modulation for Neutral-Point-Clamped Inverters." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/32277407938499774739.

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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>101<br>This thesis investigates the space vector modulation (SVM) applied to neutral-point-clamped inverters (NPC). The principle of space vector modulation is analyzed, and the MATLAB/Simulink/SimPowerSystems is used for constructing the circuit model and control module, simulation results of SVM with different switching sequence are compared, and the effect on neutral point voltage balancing, voltage utilization and harmonic distortion are discussed. Then, the ALTERA Quartus II software is used for constructing the control module of space vector modulation, and the program is downloaded to FPGA development board for realization. Actual measurement waveforms are compared with MATLAB simulation results, the consistency of each other confirms that FPGA implementation of space vector modulation function is correct.
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Lee, Shou-Fu, and 李守富. "Design of ADALINE Algorithm for Three-Level Neutral-Point-Clamped STATCOM." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/68812759617254632495.

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碩士<br>國立中山大學<br>電機工程學系研究所<br>99<br>Due to development of industries, power factor and harmonic pollution have become serious concerns in the power system. This thesis presents an adaptive linear neuron (ADALINE) - based static synchronous compensator (STATCOM) to cope with power quality issues in the industrial power system. The targeted compensating current of the STATCOM is generated based on the so-called LMS algorithm, thus the compensated system current becomes balanced and active even in reactive, unbalanced or distorted loads. In this thesis, the STATCOM is realized by using a three-level neutral point-clamped (NPC) inverter with the in-phase level-shifted sinusoidal pulse width modulation (IPLSPWM). Theoretical analysis of ADALINE method is detailed and hardware implementation of STATCOM is conducted to validate effectiveness of the proposed approach.
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46

Liu, Jun-Hui, and 劉俊輝. "Design and Implementation of Three-Phase Bi-directional Neutral-Point Clamped Converter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/45685957040465744416.

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碩士<br>國立中正大學<br>電機工程研究所<br>101<br>This thesis presents three-phase bi-directional neutral-point clamped converter, include grid-connection mode and retification mode. The converter is divided into two parts of which,one is power stagewith neutral-point clamped configuration,theother is control stage with micro-controller RX-62T to realize thefeedforward current control law. In grid-connection mode,power is transformed into AC, and injected into current to the utility grid. In rectification mode, the grid current is transformed into DC to supply rectified load. Simulated and experimental results measured from a three-phase bi-direction neutral-point clamped converterhave been presented to confirm its feasibility. Keyword: neutral-point clamped converter, high power system
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Li, Chun-Yi, and 李俊毅. "Design and Implementation of High Power Three-Phase Neutral-Point Clamped Converter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/86797905595115159644.

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碩士<br>國立中正大學<br>電機工程研究所<br>102<br>This thesis presents design and implementation of a three-phase bi-directional neutral-point clamped converter, including two operation modes: grid-connection mode and rectification mode. The converter is divided into two parts, of which one is a power stage with neutral-point clamped configuration, the other is a control stage with a single-chip micro-controller Renesas RX-62T to realize the division-summation (D-Σ) digital control law. In grid-connection mode, power is transformed into AC and injected into the utility grid. In rectification mode, the utility power is transformed to DC and supply rectified loads. Simulated and experimental results measured from a three-phase bi-directional neutral-point clamped converter have been presented to con-firm the analysis, discussion and feasibility.
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48

Ke, Chen-Hou, and 柯宸厚. "Fault Diagnosis and Tolerant Control of Three-Level Neutral Point Clamped Inverters." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/jsj7e2.

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碩士<br>國立勤益科技大學<br>電機工程系<br>105<br>This thesis presents an extension theory-based assessing method to apply fault diagnosis for inverters in motor driving systems. First, a three-level neutral point clamped (NPC) inverter was created using the PSIM software to simulate faults occurring on any power transistor in the NPC-type inverter. Also, Fast Fourier Transform was used to transform line current signals in time domain into spectrum in frequency domain for analysis of the corresponding spectrum of feature of the inverter in case of faults of different power transistors. Then, the relationship between the fault types and specific spectra was established as characteristics for extension assessment method, whereby to further create a smart fault diagnosis system for inverters. Fault-tolerant control (FTC) was further used, in the event of faulty inverter with its rated output decreased, to maintain output in balanced three phases by changing the framework of transistor connection, to reinforce the reliability of the inverter. Finally, by the results of simulation and experiment, the feasibility of the proposed smart fault diagnosis system was testified. The proposed fault diagnosing method features the advantages of minimum data, requiring no learning process, due to which fault diagnosing time is reduced, and being easy to realize. The proposed fault tolerant control strategy allows online and smooth switching in the wiring structure of the inverter.
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49

Huang, Chi-Lin, and 黃麒霖. "Design and Implementation of a High Power Three-Level Neutral-Point-Clamped Inverter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/qsa7nx.

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碩士<br>國立臺灣科技大學<br>電機工程系<br>104<br>This thesis presents the development of a 50-kilowatt three-level diode-clamp inverter. The implementation of this high power inverter includes a main power stage, modified gate-trig circuits, a DSP-based digital controller. Moreover, the thermal analysis of a forced-air-cooling sink is investigated for full-power operation. Multi-level inverters are superior to traditional two-level structures, such as less losses, lower harmonics and voltage stress, resulting in better performance. In this thesis, the inverter is designed to drive a high-power high-torque serve motor with 50-kW rated power by current control method. Thus, two current control strategies, linear current control and infinite state model predict control, are employed to achieve the control goal, in which 400Hz bandwidth and 100% over load capability are required. The two control strategies are implemented by two DSP controllers, TMS320F28069 and TMS320F28335, respectively. For dealing with the high power requirement, the layout of the main power stage is designed carefully. The inductance-free bus is used to reduce the voltage spike posed on the switches, and the modified gate-trig circuits are used to drive the high-current-rating IGBT devices properly. All these efforts prove the stability of the inverter which can operate at full power for more than two hour, even it is only a prototype. Taking the advantages of the 3-level structure, the inverter provides very high efficiency over the full operation range with the highest 98.6%. Finally, both simulation and experiment results demonstrate that the inverter not only meets the design requirement but also operates with well performance.
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50

Das, Soumitra. "Study on Pulsewidth Modulation Techniques for a Neutral-Point-Clamped Voltage Source Inverter." Thesis, 2012. http://etd.iisc.ac.in/handle/2005/3169.

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Neutral-point-clamped (NPC) three-level inverter is capable of handling higher dc bus voltage and producing output waveform of better quality than a conventional two-level inverter. The main objective of the present work is to analyze the existing PWM schemes for two-level and three-level inverters in terms of line current ripple, and to design new PWM techniques for the NPC inverter to reduce line current distortion. Various discontinuous PWM or bus-clamping PWM (BCPWM) methods for a two-level voltage source inverter are analyzed in terms of rms line current ripple, which is evaluated by integrating the error voltage (i.e. error between the applied and reference voltages). The BCPWM schemes can be broadly classified into continual-clamp PWM (CCPWM) and split-clamp PWM (SCPWM). It is shown that split-clamp PWM scheme leads to lower harmonic distortion than CCPWM scheme. Further, advanced bus-clamping PWM (ABCPWM) methods for a two-level inverter are also studied. These methods clamp each phase to the positive and negative DC terminals over certain intervals as in BCPWM schemes, and also switch each phase at double the nominal frequency in certain other intervals unlike in BCPWM. Analytical closed-form expressions are derived for the total rms harmonic distortion due to SCPWM, CCPWM and ABCPWM schemes. Existing sinusoidal and bus-clamping PWM schemes for three-level NPC inverters are also analyzed in the space vector domain. These methods are compared in terms of line current ripple analytically as well as experimentally. As earlier, closed-form expressions are derived for the harmonic distortion factors corresponding to centered space vector PWM (CSVPWM) and the various BCPWM methods. A three-level inverter can be viewed as an equivalent two-level inverter in each sixth of the fundamental cycle or hextant. This is widely used to simplify the control of an NPC inverter. Further, this approach makes it simple to extend the BCPWM and ABCPWM methods for two-level inverters to three-level inverters. Furthermore, the method of analysis of line current ripple for the two-level inverter can also be easily extended to the three-level case. The pivot vector, which is half the length of the longest voltage vectors produced by the NPC inverter, acts as an equivalent null vector for the conceptual two-level inverter. Each pivot vector can be produced by two inverter states termed as “pivot states”. Typically, in continuous modulation methods for NPC inverter such as sinusoidal PWM and centered space vector PWM, the switching sequence (i.e. the sequence in which the voltage vectors are applied) begins and ends with the same pivot vector in each subcycle, which is equivalent to a half-carrier cycle. To be more precise, the switching sequence starts with one pivot state and ends with the other in each subcycle. However, in case of BCPWM schemes, only one pivot state is used in a subcycle. The choice of pivot state results in a variety of BCPWM schemes for an NPC inverter. Different BCPWM schemes are evaluated in terms of rms line current ripple. The optimal BCPWM, which minimizes the rms current ripple, is determined for an NPC inverter, controlled as an equivalent two-level inverter. Further, four new switching sequences are proposed here for a three-level inverter, controlled as a conceptual two-level inverter. These sequences apply the pivot vector only once, but employ one of the other two vectors twice within the subcycle. These four switching sequences are termed as “ABCPWM sequences” for three-level inverter. These sequences exploit the flexibility available in the space vector approach to PWM to switch a phase more than once in a subcycle, which results in the application of an active vector twice within the subcycle. Influence of the proposed ABCPWM sequences on the line current ripple over a subcycle is studied. The various sequences are compared in terms of rms line current ripple over a subcycle. An analytical closed-form expression for rms line current ripple over a subcycle is derived in terms of reference magnitude, angle of reference voltage vector, and subcycle duration for each of the sequences. Further, closed-form expressions are also derived for the rms current ripple over a line cycle in terms of modulation index and subcycle duration, corresponding to the various sequences. The four proposed ABCPWM sequences for the NPC inverter can be grouped into two pairs of sequences. Each pair of sequences is shown to perform better than the individual sequences, if the two sequences are employed in appropriate spatial regions. Hence, with these two pairs of sequences, two hybrid PWM schemes are proposed. Finally, a hybrid PWM technique is proposed which employs all five sequences (conventional and proposed four sequences) in spatial regions where each performs the best. This is termed as “five-zone hybrid PWM”. The total harmonic distortion (THD) in the motor current, pertaining to all the proposed schemes, is studied theoretically over the entire range of linear modulation. The theoretical investigations are validated experimentally on a 2.2 kW, 415V, 4.9A, 50 Hz induction motor drive. The no-load current THD is measured over a range of fundamental frequency from 10 Hz to 50 Hz in steps of 2 Hz for the various PWM methods. Theoretical and experimental results bring out the reduction in current THD due to the proposed BCPWM schemes at fundamental frequencies of 45 Hz and above, compared to CSVPWM. The ABCPWM methods improve the performance at higher as well as lower modulation indices. Further improvement is achieved with the proposed five-zone hybrid PWM. At the rated frequency (50 Hz) of the drive, the improvement in line current distortion is around 36% with this hybrid PWM scheme over CSVPWM. The reduction in THD is also experimentally verified at different loads on the motor. The difference between the top and bottom capacitor voltages is measured at various operating conditions, corresponding to CSVPWM and the proposed schemes. No significant difference is observed in the dc neutral voltage shifts with the different proposed schemes and CSVPWM method. Thus, the proposed methods improve the THD at low and high speed ranges without appreciable worsening of the dc voltage unbalance.
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