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Rogers, L. Warren. "Synthetic space vector modulation." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34731.
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Approved for public release; distribution is unlimited<br>Alternating current motors are used throughout the fleet because of their rugged construction and nearly maintenance free operation. Since the U.S. Navy is exploring and acting on the possibilities of DC distribution systems, the need exists for simple, reliable three-phase voltage source inverter (VSI) powered induction machines. Until recently, VSIs utilized a pulse width modulation (PWM) scheme controlling the frequency and amplitude of each phase. A novel and simple hardware centered VSI controller was designed, simulated, built and tested featuring a type of space vector modulation (SVM). Design criteria evaluated such as VSI frequency response, switching losses, dead-time and SVM switching sequences were considered. Specifically, modulo-6 and 12 synthetic SVM units were evaluated for future Department of Defense use.
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Khan, Hamid. "Optimised space vector modulation for variable speed drives." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00999475.
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The dissertation documents research work carried out on Pulse Width Modulation (PWM) strategies for hard switched Voltage Source Inverters (VSI) for variable speed electric drives. This research is aimed at Hybrid Electric Vehicles (HEV). PWM is at the heart of all variable speed electric drives; they have a huge influence on the overall performance of the system and may also help eventually give us an extra degree of freedom in the possibility to rethink the inverter design including the re-dimensioning of the inverter components.HEVs tend to cost more than conventional internal combustion engine (ICE) vehicles as they have to incorporate two traction systems, which is the major discouraging factor for consumers and in turn for manufacturers. The two traction system increases the maintenance cost of the car as well. In addition the electric drives not only cost extra money but space too, which is already scarce with an ICE under the hood. An all-electric car is not yet a viable idea as the batteries have very low energy density compared with petrol or diesel and take considerable time to charge. One solution could be to use bigger battery packs but these add substantially to the price and weight of the vehicle and are not economically viable. To avoid raising the cost of such vehicles to unreasonably high amounts, autonomy has to be compromised. However hybrid vehicles are an important step forward in the transition toward all-electric cars while research on better batteries evolves. The objective of this research is to make electric drives suitable for HEVs i.e. lighter, more compact and more efficient -- requiring less maintenance and eventually at lower cost so that the advantages, such as low emissions and better fuel efficiency, would out-weigh a little extra cost for these cars. The electrical energy source in a vehicle is a battery, a DC Voltage source, and the traction motor is generally an AC motor owing to the various advantages it offers over a DC motor. Hence the need for a VSI, which is used to transform the DC voltage into AC voltage of desired amplitude and frequency. Pulse width modulation techniques are used to control VSI to ensure that the required/calculated voltage is fed to the machine, to produce the desired torque/speed. PWM techniques are essentially open loop systems where no feedback is used and the instantaneous values differ from the required voltage, however the same average values are obtained. Pulse width modulated techniques produce a low frequency signal (desired average value of the switched voltage) also called the fundamental component, along with unwanted high frequency harmonics linked to the carrier signal frequency or the PWM period. In modern cars we see more and more mechanical loads driven by electricity through digital processors. It is very important to eliminate the risk of electromagnetic interference between these systems to avoid failure or malfunction. Hence these unwanted harmonics have to be filtered so that they do not affect the electronic control unit or other susceptible components placed in the vicinity. Randomised modulation techniques (RPWM) are used to dither these harmonics at the switching frequency and its multiple. In this thesis a random modulator based on space vector modulation is presented which has additional advantages of SVM. Another EMI problem linked to PWM techniques is that they produce common mode voltages in the load. For electric machines, common mode voltage produces shaft voltage which in turn provokes dielectric stress on the motor bearings, its lubricant and hence the possibility of generating bearing currents in the machine that can be fatal for the machine. To reduce the common mode voltage a space vector modulation strategy is developed based on intelligent placement of zero vectors. (...)
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Celanovic, Nikola. "Space Vector Modulation and Control of Multilevel Converters." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29164.
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This dissertation is the result of research and development of a power conditioning system for Superconductive Magnetic Energy Storage System. The dominant challenge of this research was to develop the power conditioning system that can match slowly varying dc voltage and dc current on the super conductive magnet side with the ac voltages and ac currents on the utility side. At the same time the power conditioning system was required to provide a bi-directional power flow to the superconductive magnet.
The focus of this dissertation is a three-level diode clamped dc-ac converter which is a principle part of the power conditioning system. Accordingly, this dissertation deals with the space vector modulation of three-level converters and introduces a computationally very efficient three-level space vector modulation algorithm that is experimentally verified.
Furthermore, the proposed space vector modulation algorithm is successfully generalized to allow equally efficient, real time implementation of space vector modulation to dc-ac converters with virtually any number of levels. The most important advantage of the proposed concept is in the fact that the number of instructions required to implement the algorithm is almost independent from the number of levels in a multilevel converter.
More on the side of the control of multilevel converters, the particular attention in this dissertation is paid to the problem of charge balance in the split dc-link capacitors of three-level neutral-point-clamped converters. It is a known fact that although the charge balance in the neutral point can be maintained on a line cycle level, a significant third harmonic current flows into the neutral point for certain loading conditions, causing the neutral point voltage ripple. The logical consequence of that ripple is the deteriorated quality of the output voltage waveforms as well as the increased voltage stress on the switching devices.
This was the motivation to more carefully explore the loading conditions that cause the unbalance, as well as to study the fundamental limitations of dc-link capacitor charge balancing algorithms. As a part of that work, a new model of the neutral point current in the rotating coordinate frame is developed as a tool in investigation of theoretical limitations and in providing some intuitive insight into the problem. Additionally, the low frequency ripple is quantified and guidelines are offered that can help size the dc-link capacitors.
Because the study of the neutral point balance identified the loading conditions, that under some possible system constraints, cause an unavoidable neutral point voltage ripple, a feed forward type of control method is developed next. The proposed feed forward algorithm can effectively prevent the neutral point voltage ripple from creating distortions in the converter output voltage under all loading conditions and without causing additional disturbance in the neutral point voltage. The feed forward method is developed for a sine triangle as well as for the space vector type PWM algorithm.
The simulation results that include the full dynamic model of the converter and load system validate the feed forward approach and prove that the feed forward algorithm can effectively compensate the effect of the neutral point voltage ripple. The simulation results are than experimentally verified.<br>Ph. D.
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Mason, Nicholas J. "Space vector modulation of a 4-leg matrix converter." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12266/.
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This thesis covers the investigation into the use of Space Vector Modulation for the control of a 4-leg matrix converter, which is capable of providing a 3-phase plus neutral supply from a standard balanced 3-phase source. Traditional 3x3 matrix converters have limited use in this application as they are only capable of supplying a balanced three-phase load. It would be desirable to be able to power unbalanced and non-linear loads, requiring that the converter provides a neutral connection. As with voltage source inverters, this goal can be achieved by extending the number of output legs in the matrix converter to four. In this thesis, a new Space Vector Modulation technique is proposed for this 4-leg, or 3x4, matrix converter. This technique is an extension of the method currently in use on 3x3 matrix converters, and so it allows the de-coupled control of both the input and output. The thesis then goes onto cover the build of a demonstration converter, looking at the different aspects which make up a converter, to finally go on to prove the theory, and a set of results are presented to validate this.
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Prasad, V. Himamshu. "Analysis and Comparison of Space Vector Modulation Schemes for Three-Leg and Four-Leg Voltage Source Inverters." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36578.
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Several space vector modulation schemes have been analyzed for three-leg and four-leg voltage source inverters. The analysis is performed with respect to a) switching losses, b) total harmonic distortion, c) peak-to-peak ripple in the line current and d) the ease of digital implementation. The analysis is performed over the entire range of modulation index and for varying load power factors (leading and lagging) under both balanced and unbalanced load conditions. The analysis shows that the performance of four-leg inverters is similar to three-leg inverters for various space vector modulation schemes. The analysis also verifies the fact that a modulation scheme with good harmonic performance usually has high switching losses and vice-versa. The analysis is verified using simulation and experiments. A novel algorithm for the calculation of total harmonic distortion of PWM signals has been proposed.<br>Master of Science
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Kronberg, Anders. "Salient Pole Motor Inverter Design : with Implementation of Space Vector Modulation." Thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192994.
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The researchers at the Department of Electricity at Uppsala University has recently entered the field of electric motor design, however no real knowledge of motor control of salient pole permanent magnet motors exists in the department. This master thesis is a continuation of a previous bachelor thesis that analyses the theory behind the control and simulating two different control methods. The two methods are here discarded for their high torque ripple. A third method is therefore implemented in this thesis to improve the performance. This thesis will present the design and construction of an inverter for driving of a 30kW permanent magnet motor intended for vehicle propulsion. The work is divided into two parts, the power electronics and the control system hardware and software. The results shows a working concept for a drive system, but further testing and improvements are needed to achieve maximum efficiency of the whole system.<br>Ett drivsystem för högeffektiva elektriska fordonsmotorer har konstruerats och testats på en 30kW motor utvecklad på Uppsala universitet. Resultaten visar att systemet fungerar, men att det även finns behov av förbättringar. Med tanke på de senaste årens forskning och debatt om peak oil och en ökande mängd växthusgaser i atmosfären har det blivit tydligare att världens energikonvertering måste förändras för ett mer hållbart samhälle. Avdelningen för elektricitetslära på Uppsala universitet har det senaste decenniet fokuserat på utveckling av förnyelsebara energikällor, så som vind-, våg-, vatten- och marin strömkraft. Med samma verktyg och metoder som använts vid utvecklingen av högeffektiva generatorer har de nyligen gett sig in på området elektriska motorer för fordonsframdrift. En av elbilens nackdelar är dess räckvidd, för att kunna konkurrera med dagens bilar är det därför viktigt att optimera verkningsgraden i de olika delsystemen mellan laddkontakt och hjul. I detta arbete presenteras en metod i vilken de tre fasernas drivelektronik styrs som en enhet istället för att behandla den som tre oberoende enheter. Detta möjliggör en 15.4% högre drivspänning till motorn, vilket leder till lägre strömmar och förluster för samma uteffekt. Arbetet omfattar konstruktion av kraftelektronik, styrelektronik och programmering av styrelektroniken, samt test och verifiering av hela systemet.
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Narayanan, G. "Synchronised Pulsewidth Modulation Strategies Based On Space Vector Approach For Induction Motor Drives." Thesis, Indian Institute of Science, 1999. https://etd.iisc.ac.in/handle/2005/139.
Full textAbstract:
In high power induction motor drives, the switching frequency of the inverter is quite low due to the high losses in the power devices. Real-time PWM strategies, which result in reduced harmonic distortion under low switching frequencies and have maximum possible DC bus utilisation, are developed for such drives in the present work.
The space vector approach is taken up for the generation of synchronised PWM waveforms with 3-Phase Symmetry, Half Wave Symmetry and Quarter Wave Symmetry, required for high-power drives. Rules for synchronisation and the waveform symmetries are brought out. These rules are applied to the conventional and modified forms of space vector modulation, leading to the synchronised conventional space vector strategy and the Basic Bus Clamping Strategy-I, respectively. Further, four new synchronised, bus-clamping PWM strategies, namely Asymmetric Zero-Changing Strategy, Boundary Sampling Strategy-I, Basic Bus Clamping Strategy-II and Boundary Sampling Strategy-II, are proposed. These strategies exploit the flexibilities offered by the space vector approach like double-switching of a phase within a subcycle, clamping of two phases within a subcycle etc. It is shown that the PWM waveforms generated by these strategies cannot be generated by comparing suitable 3-phase modulating waves with a triangular carrier wave.
A modified two-zone approach to overmodulation is proposed. This is applied to the six synchronised PWM strategies, dealt with in the present work, to extend the operation of these strategies upto the six-step mode. Linearity is ensured between the magnitude of the reference and the fundamental voltage generated in the whole range of modulation upto the six-step mode. This is verified experimentally.
A suitable combination of these strategies leads to a significant reduction in the harmonic distortion of the drive at medium and high speed ranges over the conventional space vector strategy. This reduction in harmonic distortion is demonstrated, theoretically as well as experimentally, on a constant V/F drive of base frequency 50Hz for three values of maximum switching frequency of the inverter, namely 450Hz, 350Hz and 250Hz.
Based on the notion of stator flux ripple, analytical closed-form expressions are derived for the harmonic distortion due to the different PWM strategies. The values of harmonic distortion, computed based on these analytical expressions, compare well with those calculated based on Fourier analysis and those measured experimentally.
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Narayanan, G. "Synchronised Pulsewidth Modulation Strategies Based On Space Vector Approach For Induction Motor Drives." Thesis, Indian Institute of Science, 1999. http://hdl.handle.net/2005/139.
Full textAbstract:
In high power induction motor drives, the switching frequency of the inverter is quite low due to the high losses in the power devices. Real-time PWM strategies, which result in reduced harmonic distortion under low switching frequencies and have maximum possible DC bus utilisation, are developed for such drives in the present work.
The space vector approach is taken up for the generation of synchronised PWM waveforms with 3-Phase Symmetry, Half Wave Symmetry and Quarter Wave Symmetry, required for high-power drives. Rules for synchronisation and the waveform symmetries are brought out. These rules are applied to the conventional and modified forms of space vector modulation, leading to the synchronised conventional space vector strategy and the Basic Bus Clamping Strategy-I, respectively. Further, four new synchronised, bus-clamping PWM strategies, namely Asymmetric Zero-Changing Strategy, Boundary Sampling Strategy-I, Basic Bus Clamping Strategy-II and Boundary Sampling Strategy-II, are proposed. These strategies exploit the flexibilities offered by the space vector approach like double-switching of a phase within a subcycle, clamping of two phases within a subcycle etc. It is shown that the PWM waveforms generated by these strategies cannot be generated by comparing suitable 3-phase modulating waves with a triangular carrier wave.
A modified two-zone approach to overmodulation is proposed. This is applied to the six synchronised PWM strategies, dealt with in the present work, to extend the operation of these strategies upto the six-step mode. Linearity is ensured between the magnitude of the reference and the fundamental voltage generated in the whole range of modulation upto the six-step mode. This is verified experimentally.
A suitable combination of these strategies leads to a significant reduction in the harmonic distortion of the drive at medium and high speed ranges over the conventional space vector strategy. This reduction in harmonic distortion is demonstrated, theoretically as well as experimentally, on a constant V/F drive of base frequency 50Hz for three values of maximum switching frequency of the inverter, namely 450Hz, 350Hz and 250Hz.
Based on the notion of stator flux ripple, analytical closed-form expressions are derived for the harmonic distortion due to the different PWM strategies. The values of harmonic distortion, computed based on these analytical expressions, compare well with those calculated based on Fourier analysis and those measured experimentally.
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Zhang, Richard S. "High Performance Power Converter Systems for Nonlinear and Unbalanced Load/Source." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/29314.
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This dissertation covers three levels of issues and solutions dealing with unbalanced and/or nonlinear situations in power electronic systems, namely power converter level, power converter system level, and large-scale power electronics system level.
At power converter level, after review of traditional PWM methods, especially two-dimensional space vector modulation schemes, three-dimensional space vector modulation schemes are proposed for four-legged voltage source converters, including inverters and rectifiers. The four-legged power converters with three-dimensional space vector modulation schemes have a better DC link voltage utilization and result in a low distortion. It is an effective solution to provide the neutral point for a three-phase four-wire system and to handle the neutral current due to unbalanced load or source and nonlinear loads. Comprehensive design guidelines for a four-legged inverter are presented. The four-legged rectifier is also presented which allows not only fault tolerant operation, but also provides the flexibility of equal resistance, equal current, or equal power operation under unbalanced source.
Average large-signal models of four-legged power converters in both the a-b-c and d-q-o coordinates are derived. Small signal models are obtained in the d-q-o rotating coordinates. Voltage control loops are designed in the d-q-o coordinates for a high power utility power supply. Performance is studied under various load conditions.
At the power converter system level, the load conditioner concept is proposed for high power applications. A power converter system structure is proposed which consists of a high-power low-switching frequency main inverter and a low-power high-switching frequency load conditioner. The load conditioner performs multiple functions, such as active filtering, active damping, and active decoupling with a high current control bandwidth. This hybrid approach allows the overall system to achieve high performance with high power and highly nonlinear loads.
At the large-scale power electronics system level, the nonlinear loading effect of load converters is analyzed for a DC distribution system. Two solutions to the nonlinear loading effect are presented. One is to confine the nonlinear load effect with the sub-converter system, the other is to use a DC bus conditioner. The DC bus conditioner is the extension of the load conditioner concept.<br>Ph. D.
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Cuadros, O. Carlos E. "Modified Space Vector Modulation for a Zero-Voltage Transition Three-Phase to DC Bi-directional Converter." Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/36712.
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A modified space vector modulation algorithm for a zero-voltage transition three-phase voltage source inverter/boost rectifier is presented. The converter is intended for high performance medium power applications requiring bi-directional power flow. The proposed modified space vector modulation allows the main switches to be operated with constant frequency and soft switching for any phase shift between the three-phase currents and voltages. The modulation algorithm also eliminates any low frequency distortion caused by the zero-voltage transition and can be extended to other soft-switching PWM three-phase converters. Experimental verification of the proposed algorithm is also presented as well as a comparison to the hard switched PWM converter.<br>Master of Science
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Treharne, William. "The optimal application of common control techniques to permanent magnet synchronous motors." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:e8e2902a-d383-400f-9be0-bb3c11b3899c.
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Permanent magnet synchronous motors are finding ever increasing use in hybrid and electric vehicles. This thesis develops a new control strategy for Permanent Magnet Synchronous Motors (PMSMs) to reduce the motor and inverter losses compared to conventional control techniques. The strategy utilises three common control modes for PMSMs; brushless DC with 120°E conduction, brushless DC with 180°E conduction, and brushless AC control. The torque and power output for each control mode is determined for an example motor system using a three phase axial flux YASA motor and an IGBT inverter. The loss components for the motor and inverter are also estimated using a combination of analytical and simulation techniques and results are then validated against experimental measurements. Efficiency maps for each control mode have been used to determine an optimal mode utilisation strategy, which minimises the total system losses and maximises the available motor torque output. The proposed control strategy switches between the three control modes without interruption of motor torque to maximise the system efficiency for the instantaneous operating speed and demanded torque output. The benefits of the new strategy are demonstrated using an example vehicle over a simulated drive cycle. This yields a 10% reduction in losses compared to conventional brushless AC control.
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Krohn, Austin Bengoechea. "Electro-Thermal Dynamics and the Effects of Generalized Discontinuous Pulse Width Modulation Algorithms on High Performance Variable Frequency Drives." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397643253.
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Carnielutti, Fernanda de Morais. "Estratégias de modulação para conversores multiníveis em cascata sob faltas." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/8497.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Multilevel converters are being increasingly employed nowadays, specially in mediumand
high-voltage industrial applications. Even though these converters are able to
synthesize output line-to-line voltages with a high number of levels, close to a sinusoidal
waveform, their modulation is more complex than the one for two- and three-level
converters. In this context, this dissertation proposes new modulation strategies for
multilevel converters, specifically symmetrical and asymmetrical cascaded multilevel ones,
composed of many full-bridges, or power cells, per phase. If the converter has one
or more faulty cells, they can be bypassed and the converter can continue to feed the
load, increasing the process reliability. However, the converter phase voltages must be
modified so as to keep the output line-to-line voltages balanced. With the objective
of proposing modulation strategies that allow the cascaded multilevel converters to
satisfactorily operate under these conditions, an extensive bibliographical review of the
existing modulation techniques has been carried out. The carrier-based modulation
approaches were studied first. It could be noticed that all these strategies belong to a
larger set of solutions for the obtention of the converter modulating phase voltages. This
set is derived in this work, resulting in a generalized geometrical modulation strategy for
symmetrical and asymmetrical cascaded multilevel converters with any number of levels
and operating under normal or faulty conditions. As the faulty cells are restrictions for
converter operation, for each fault condition the region that contains all the possible
converter common-mode voltages, that compensate for the loss of cells, is derived. The
choice of a common-mode pertaining to this set allows the entire converter synthesis
capability to be explored. The modulating voltages are the sum of the reference and the
common-mode voltages, maximizing the amplitudes of the output line-to-line voltages.
For asymmetrical cascaded multilevel converters, the voltages synthesized by the highervoltage
cells are restrictions for the operation of the lower-voltage ones. Concerning
the Space Vector (SV) modulation, it was derived only for the asymmetrical cascaded
multilevel converter. The higher-voltage and lower-voltage cells switch, respectively, with
low frequency by the choice of the nearest vector to the reference, and with high frequency,
by the choice of the three nearest vectors to the reference, in one switching period. The
voltage synthesized by the higher-voltage cells is subtracted from the reference, resulting
in the new reference for the lower-voltage cells, and so successively, until the cells with the
lowest voltages. A specific switching sequence is defined off-line for each sector of the SV
diagram. The algorithm is carried out in a modified αβo coordinate system, resulting in
switching vector with only integer entries. The choice of the switching vectors considers all
the possible redundancies in abc coordinates. At last, simulation and experimental results
Abstract
that prove the good performance of the proposed modulation strategies are presented.<br>Conversores multiníveis são cada vez mais empregados, especialmente em aplicações
industriais de média e alta tens~ao. Apesar de serem capazes de sintetizar tensões de linha de saída com um grande número de níveis, se aproximando de uma forma de onda
senoidal, sua modulação é mais complexa, quando comparada com conversores de dois ou
três níveis. Neste contexto, esta dissertação propõe novas estratégias de modulação para conversores multiníveis, especificamente multiníveis em cascata simétricos e assimétricos,
compostos por diversos full-bridges, ou células de potência, por fase. Caso uma ou mais células sofram faltas, estas podem ser retiradas de operação, e o conversor pode continuar
a alimentar a carga, aumentando a confiabilidade do processo. Contudo, as tensõe de fase do conversor devem ser modificadas, a fim de manter as tensões de linha de saída
equilibradas. Com o objetivo de propor estratégias de modulação que permitam aos conversores multiníveis em cascata operar satisfatoriamente nestas condições, foi realizada
uma extensa pesquisa bibliográfica a respeito dos métodos de modulação já existentes
na literatura. Primeiramente, foram estudadas estratégias de modulação baseadas em portadora. Pode-se perceber que estas pertencem a um conjunto maior de possíveis
soluções para a obtenção das tensões modulantes para as fases do conversor. Este conjunto
é derivado neste trabalho, resultando em uma estratégia generalizada de modulação com abordagem geométrica para conversores multiníveis em cascata simétricos e assimétricos
com qualquer número de níveis, em operação normal ou sob faltas. Como as células com falta são restrições para o funcionamento do conversor, para cada condição de falta é
definida a região que contém todas as possíveis tensões de modo comum que podem ser sintetizadas pelo conversor a fim de compensar a perda de células. A escolha de uma tensão
de modo comum pertencente a este conjunto permite explorar toda a capacidade de síntese de tensão do conversor. As tensões modulantes são obtidas como a soma das tensões
de referência de fase e de modo comum, maximizando as amplitudes das componentes fundamentais das tensões de linha de saída. Para os conversores multiníveis em cascata
assimétricos, as tensões sintetizadas pelas células de maior tensão são restrições para a operação das demais. Quanto à modulação Space Vector (SV), optou-se por desenvolvê-la
apenas para conversores multiníveis em cascata assimétricos. As células de alta tensão comutam em baixa frequência pela escolha do vetor mais próximo da referência, e as células de baixa tensão comutam em alta frequência pela escolha dos três vetores mais
próximos da referência, em um período de comutação. A tensão sintetizada pelas células
de alta tensão é subtraída da referência, resultando na nova referência para as próximas
células, e assim sucessivamente até as células de menor tensão. Para cada setor do Resumo diagrama SV é definida off-line uma sequência de comutação específica. O algoritmo implementado realiza todos os cálculos em um sistema de coordenadas αβo modificado,
resultando em vetores de comutação apenas com elementos inteiros. A escolha dos vetores
de comutação a serem implementados considera todas as suas possíveis redundâncias em coordenadas abc. Por fim, são apresentados resultados de simulação e experimentais que
comprovam o ótimo desempenho das estratégias de modulação propostas neste trabalho.
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Moraes, João Batista. "Estratégias de modulação por largura de pulso." reponame:Repositório Institucional da UFABC, 2016.
Find full textAbstract:
Orientador: Prof. Dr. José Alberto Torrico Altuna<br>Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016.<br>O presente trabalho estuda as técnicas de modulação de inversores trifásicos com aplicação principal em controle de máquinas de indução. Na primeira parte é realizada a pesquisa bilbiográfica considerando as principais técnicas de modulação, sendo apresentado depois o princípio de funcionamento destes moduladores. A operação do inversor é estudada apresentando os sinais trifásicos gerados a partir de uma fonte de tensão C.C. É feita a descrição do PWM senoidal baseado em portadora seno¿triangulo e o PWM baseado em vetores espaciais. Também é apresentada uma estratégia de modulação na região de sobre modulação. O principio de modulação aleatorea é estudado citando as contribuições principais nesta área. Finalmente é apresentada a modulação por eliminação seletiva de harmônicas e as principais referências. São apresentados resultados de simulação dos principais métodos de modulação considerando os principais parâmetros de desempenho. Como aplicação de técnicas de modulação em inversores, é apresentada uma estratégia para compensação de tensão usando restauradores dinâmicos de tensão DVR.<br>This dissertation studies modulation techniques for three-phase inverters intended to induction motor control. The First part is literature review regarding the main modulation techniques. Secondly it is described the operation principle of voltage source inverter showing three-phase signals generated from a C.C voltage. It is made a PWM description based on carrier (sine-triangle) and space vector modulation in both linear and over modulation region. The principle of random modulation is presented mentioning the main contributions in this area. It is showed the modulation by selective elimination of harmonics and the main references. Simulation results from modulation schemes are presented taking into account performance of each method. As application it is presented a strategy for Dynamic Voltage Restorer (DVR).
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Nusair, Ibrahim Rakad. "Comparison Between PWM and SVPWM Three-Phase Inverters in Industrial Applications." Youngstown State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1355949821.
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Carnielutti, Fernanda de Morais. "Modulação space vector para conversores multiníveis com células assimétricas em cascata sob condições de faltas." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/3694.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>This Thesis proposes a Space Vector Modulation for cascaded miltilevel converters with
asymmetric cells under normal conditions and with faults in the power cells, avoiding
converter saturation as much as possible. The switching state vectors and the voltage
references are represented in the output line-to-line voltages coordinate system. Under
this representation, the switching state vectors have only integer entries, easing the implementation
of the proposed algorithm. The modulation is developed in a way such as
to guarantee that the higher voltage cells switch at low frequency by the choice of only
one vector per switching period, minimizing the switching losses. For the lower voltage
cells (1pu), that switch with PWM, three algorithms were developed for defining the switching
sequences: (i) offline, (ii) online and (iii) hybrid, where a carrier-based geometrical
modulation and the SV are mixed in a simple and unified approach. The algorithm is
described in a generic way, for converters with any number of levels, and then, simulation
and experimental results are shown for, respectively, cascaded miltilevel converters with
asymmetric cells with DC bus voltages ratio of 1:2:4pu and 1:2pu. The algorithm does
not use conventional separation lines to find where the multiple references for the power
cells are located inside the SV diagram. It also avoids converter saturation and, when it is
unavoidable, detects its occurrence and changes the operation mode to overmodulation.
This one is treated as a modification of the orignal algorithm, allowing the converter to
operate with a wider range of modulation indexes and fault conditions. It is shown that
two overmodulation modes can occur: in the first, there is still an area inside the SV diagram
where overmodulation is avoided, and, in the second, the converter overmodulates
during almost all the time. Modulation strategies are proposed for both cases, including
the insertion of a bandpass filter in the second case, so as to minimize the distortions and
unbalances that arise on the converter output line-to-line voltages during this operation
mode. For the overmodulation, simulation and experimental results are also shown for
cascaded miltilevel converters with asymmetric cells with DC bus voltages ratio of 1:2:4pu
and 1:2pu. Finally, the final conclusions are drawn and future works are proposed.<br>Esta Tese propõe uma estratégia de modulação Space Vector (SV) para conversores
multiníveis com células assimétricas em cascata durante operação normal e com faltas nas
células de potência, garantindo a não ocorrência de saturação do conversor sempre que esta
não for desejada, especialmente durante faltas. Os vetores de comutação e as referências de
tensão são representados no sistema de coordenadas das tensões de linha de saída. Desta
forma, os vetores de comutação apresentam apenas coordenadas inteiras, facilitando a
implementação do algoritmo proposto. A modulação é desenvolvida de forma a garantir
que as células de maior tensão comutem em baixa frequência, pela escolha de apenas
um vetor por período de comutação, minimizando as perdas de comutação do conversor.
Para as células de menor tensão (1pu), que comutam com PWM, foram desenvolvidos três
algoritmos para definição das sequências de comutação: definição (i) offline, (ii) online e
(iii) híbrida, onde as modulações geométrica com portadora e SV são mescladas em uma
abordagem única e simplificada. O algoritmo SV é descrito de maneira genérica, para
conversores com qualquer número de níveis, e, na sequência, são apresentados resultados
de simulação e experimentais para, respectivamente, conversores multiníveis com células
assimétricas em cascata com razão das tensões dos barramentos CC de 1:2:4pu e 1:2pu.
Este algoritmo não faz uso de retas de separação convencionais para encontrar os domínios
onde as múltiplas referências para as células de potência se encontram dentro do diagrama
SV. Também evita ao máximo a saturação do conversor, e, quando esta é inevitável,
detecta sua ocorrência e muda o modo de operação para sobremodulação. Esta é tratada
por meio de modificações no algoritmo original, permitindo a operação do conversor com
um maior número de índices de modulação e condições de falta. É mostrado que existem
dois casos de sobremodulação durante faltas nas células de potência: no primeiro, ainda há
uma área no interior do diagrama SV onde a sobremodulação é evitada, e, no segundo, o
conversor sobremodula durante praticamente todo o tempo. São propostas estratégias de
modulação para ambos os casos, incluindo a inserção de um filtro passa-faixa no segundo,
para minimizar as distorções e os desequilíbrios que surgem nas tensões de linha de saída
do conversor, quando este se encontra neste modo de operação. Para a sobremodulação,
também são apresentados resultados de simulação e experimentais para os conversores
multiníveis com células assimétricas em cascata com razão das tensões dos barramentos
CC de 1:2:4pu e 1:2pu. Por fim, as conclusões finais são apresentadas e são propostos
trabalhos futuros.
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Johansson, Tomas. "Active rectification and control of magnetization currents in synchronous generators with rotating exciters : Implementation of the SVPWM algorithm using MOSFET technology." Thesis, Uppsala universitet, Elektricitetslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257433.
Full textAbstract:
This thesis aims to design and build a power electronics system for the rectification and control of magnetization currents in synchronous generators with rotating exciters.The rotating exciter provides three-phase AC while the generator rotor needs DC with a high degree of control. The system needs to be able to rectify the three-phase AC to a stable DC without unwanted harmonic content, neither on the DC or the AC side. For control purposes it is also important that the current in the rotor can be changed very swiftly, preferably by several amperes during a single revolution ofthe machine.The system of choice is a synchronous rectifier bridge consisting of six MOSFET switches operated using the Space vector pulse width modulation (SVPWM) algorithm. This method gives a stable and controllable DC voltage while it keeps the harmonic content of the input currents at a minimum. However the DC voltage will always be higher than the peak line-to-line voltage from the exciter. To be able to lower the voltage below this value a Buck-converter is placed after the rectifier bridge.To gain a higher degree of control of the current density in the rotor windings the windings have been subdivided into three parts. To provide individual control of the current in the three rotor parts each part have been outfitted with a Push and Pull H-bridge.The proposed system has been both simulated using MATLAB Simulink and built and tested in the laboratory with satisfactory results.<br>I detta examensarbete presenteras ett kraftelektroniksystem för förbättrad kontroll av magnetiseringsstömmar i vattenkraftsgeneratorer som är utrustade med roterande matare.Generatorer används för att konvertera energi från rörelseenergi till elektrisk energi. Detta görs genom att man utsätter spolar för varierande magnetfält; då induceras spänning i spolarna. I vattenkraftsgeneratorer används oftast stora elektromagneter placerade i en rotor för att skapa dessa magnetfält. För att magnetisera elektromagneterna behövs ström som på något sätt måste överföras mellan den statiska och den roterande sidan i generatorn. Traditionellt görs detta med hjälp av släpringar och kolborstar som genom mekanisk kontakt överför elektriciteten. En roterande matare kan beskrivas som en liten generator som har sina elektriska utgångar på den roterande sidan istället för på den statiska sidan. Genom att placera en roterande matare på samma axel som den stora generatorn kan man istället alstra den elektricitet som behövs för att magnetisera generatorn direkt på den roterande sidan. Däregenom undviks många problem som är associerade med lösningen med släpringar.Den roterande mataren ger dock växelström medan magnetiseringsströmmen måste vara likström. Det är här kraftelektroniken kommer in i bilden. Det finns flera sätt att åstadkomma likriktning av ström. I det här projektet har ett fullständigt aktivt system byggts. Systemet är uppbyggt av transistorer av MOSFET typ och kan kontrolleras trådlöst med hjälp av Bluetoothteknik. Systemet ger full kontroll över strömmar och spänningar både på växelströmssidan och på likströmssidan och ska användas till en testgenerator på avdelningen för ellära vid Uppsala Universitet. Där ska den utökade kontroll som systemet ger förutsättningar till användas för att undersöka hur den här typen av system kan optimera de magnetiska krafterna inuti generatorn. En sådan optimering kan minska vibrationerna i generatorn och därigenom minska slitaget på lager och andra delar i maskinen.
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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.
Full textAbstract:
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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SHALINI. "DESIGN AND CONTROL OF CONVERTERS FOR SOLAR WATER PUMPING APPLICATION." Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18895.
Full textAbstract:
This thesis presents designing and modelling of water pumping system powered by solar
energy and comprising of BLDC motor drive. It manifests the performance comparison
between Zeta, Sepic and Cuk converter based output conditioning of SPV array as well. As
the solar insolation level is not constant, SPV array output is controlled using Maximum
Power Point Tracking (MPPT) along DC-DC converter in order to ensure maximum power
usage from SPV array. MPPT is implemented using Incremental Conductance (INC)
algorithm along with Zeta, Sepic and Cuk converters to power BLDC motor drive. The DC-
DC converters along with the entire simulation are analyzed for peak insolation level as well
as varying insolation level and comparison has been performed on the basis of performance
characteristics. The BLDC motor is fed using a six-pulse converter which is controlled using
Space Vector Pulse Width Modulation (SVPWM) technique which facilitate maximization
of efficiency of whole system. The simulation results are obtained from model created in
MATLAB (Simulink) environment.
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Nekvapil, Jan. "Řízení trojfázového asynchronního motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228416.
Full textAbstract:
This theses concern proposal and implementation asynchronous motor control algorithm in the processor DSP56F807 from the manufacturer Freescale. The complex design of applicable control algorithm and suitable interconnection with processor and outer component is solved in this work. Integral part is also choosing of suitable power elements of inverter and sensors.
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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.
Full textAbstract:
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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Pou, Félix Josep. "Modulation and control of three-phase PWM multilevel converters." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6327.
Full textAbstract:
La present tesi doctoral estudia els inversors trifàsics multinivell del tipus denominat de díodes de fixació (diode-clamped converters). Aquests convertidors poden generar tres o més nivells de tensió a cada fase de sortida, i normalment s'apliquen a sistemes de gran potència ja que poden treballar amb tensions majors que els inversors clàssics. L'anàlisi es centra fonamentalment en la topologia de tres nivells, tot i que també es realitzen contribucions per a convertidors de més nivells. Els principals objectius són la proposta de nous algorismes de modulació vectorial PWM de processat ràpid, l'estudi i la compensació dels efectes dels desequilibris de les tensions dels condensadors del bus de continua, i l'anàlisi de llaços de control avançat.<br/>S'han desenvolupat diversos models que han permès obtenir resultats de simulació de les tècniques de modulació i control proposades. A més, gràcies a l'estada d'un any de l'autor al Center for Power Electronics Systems (CPES) a Virginia Tech, USA, la tesi també inclou resultats experimentals que consoliden les conclusions i metodologies presentades. Les principals contribucions es resumeixen a continuació. <br/>Es presenta un nou algorisme de modulació vectorial PWM que aprofita simetries del diagrama vectorial per a reduir el temps de processat. S'analitzen i es quantifiquen les oscil·lacions de tensió de baixa freqüència que apareixen en el punt central dels condensadors del convertidor de tres nivells. Aquesta informació permet dimensionar els condensadors donades les especificacions d'una determinada aplicació.<br/>L'algorisme de modulació també s'aplica a convertidors de més nivells. Pel cas concret del convertidor de quatre nivells, es comprova l'existència de corrents continus en els punts mitjos dels condensadors que fan que els sistema sigui inestable. Es determinen gràficament les zones d'inestabilitat. <br/>Es presenta un nou i eficient algorisme de modulació vectorial feedforward en el convertidor de tres nivells que és capaç de generar tensions trifàsiques de sortida equilibrades, malgrat l'existència de desequilibris en les tensions dels condensadors.<br/>S'estudien els efectes negatius de càrregues lineals desequilibrades i càrregues no lineals en el control de les tensions dels condensadors. Es justifica que l'existència d'un quart harmònic en els corrents de càrrega pot inestabilitzar el sistema. És determina la màxima amplitud tolerable d'aquest harmònic.<br/>S'estudia la millora en l'equilibrat de les tensions d'una connexió de dos convertidors de tres nivells al mateix bus de continua (back-to-back connection). Un exemple d'aplicació pràctica és la conversió AC/DC/AC per a l'accionament de motors d'alterna treballant amb factor de potència unitari.<br/>Finalment s'aplica un controlador òptim al convertidor de tres nivells treballant com a rectificador elevador (boost). El llaç de control LQR (Linear Quadratic Regulator) es simplifica donat que la tasca d'equilibrat de les tensions dels condensadors es dur a terme en el mateix modulador.
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Wu, Jia. "Implementation of a 100kW Soft-Switched DC Bus Regulator Based on Power Electronics Building Block Concept." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/32468.
Full textAbstract:
Power electronics building blocks (PEBBs) are standardized building blocks used to integrate power electronics systems. The PEBB approach can achieve low cost, high redundancy, high reliability, high flexibility and easy maintenance for large-scale power electronics systems. This thesis presents the implementation of a 100kW PEBB-based soft-switched bus regulator for an 800V DC distributed power system. The zero current transition (ZCT) soft-switching technique is used to improve the performance of the bus regulator by minimizing switching loss and improving overall efficiency.
PEBB modules and a digital control building block are the subsystems of the DC bus regulator. This thesis addresses the design issues at subsystem and system levels. These include: operational principles and design of ZCT PEBB modules; design and implementation of the digital control block, based on DSP and EPLD; and modeling and control design of the DC bus regulator.
There are several considerations when using the ZCT soft-switching technique in three-phase applications: the timing of the auxiliary switch gate signals must be arranged differently; there are low-frequency harmonics caused by the pulse width limits; and there is high thermal stress on the resonant capacitors. These issues are resolved by utilizing the sensed phase current information and the design freedom in the PWM modulator. A PWM modulation technique is proposed that can considerably reduce the switching events and further remove the associated loss while keeping THD low. Reduced switching events alleviate the thermal issue of the resonant capacitors. The same modulation technique can avoid the low-frequency harmonics caused by the pulse width limits and double the sampling frequency. The phase current information is used to deal with the control timing issue of the auxiliary switches and to control the three-phase soft-switching operation in order to achieve better efficiency. Additionally, the phase current information is used to implement dead time compensation to reduce THD.
The soft-switched DC bus regulator has been tested up to a 100kW power level with 20kHz switching frequency. Experimental results demonstrate that high performance of the DC bus regulator is accomplished in terms of wide control bandwidth, low THD, unity power factor, high efficiency and high power density.<br>Master of Science
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Espindola, Marcos Fernando. "Estudo e implementação de inversor de tensão a três níveis com modulação em largura de pulsos por vetores espaciais aplicado ao controle vetorial de motor síncrono de imãs permanentes = Study and implementation of three level voltage inverter with space vector modulation by pulse width modulation applied to vector control of permanent magnet synchronous motor." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259011.
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Orientadores: Ernesto Ruppert Filho, Marcelo Gradella Villalva<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação<br>Made available in DSpace on 2018-08-21T14:53:53Z (GMT). No. of bitstreams: 1
Espindola_MarcosFernando_M.pdf: 5114547 bytes, checksum: 1601ee84cd6d17c671ba644a288c398d (MD5)
Previous issue date: 2012<br>Resumo: Apresenta-se a implementação de um inversor trifásico de tensão a três níveis para ser utilizado no controle de velocidade de um motor síncrono trifásico a imãs permanentes usando o método de controle vetorial. Realizou-se o estudo, projeto e construção de um inversor de tensão a três níveis com neutro grampeado ou inversor NPC neutral point clamped. Utilizou-se modulação em largura de pulsos por vetores espaciais no controle vetorial de velocidade do motor. Foram realizadas simulações do sistema proposto usando os aplicativos computacionais Matlab/Simulink e PSIM. Realizou-se em seguida uma montagem experimental constituída de um motor síncrono a imãs permanentes de 0,75 kW acoplado a um freio eletromagnético que lhe serviu de carga mecânica. O sistema motor e carga foi acionado pelo inversor com modulação em largura de pulsos por vetores espaciais e os resultados obtidos do controle de velocidade realizado, incluindo reversão de velocidade e frenação do motor, são apresentados no trabalho. Comparou-se também o desempenho de um inversor a três níveis usando modulação em largura de pulsos por vetores espaciais com o desempenho de um inversor a dois níveis usando modulação em largura de pulsos por vetores espaciais na alimentação de uma carga resistiva. Resultados de simulação e resultados experimentais são apresentados. Neste trabalho realizou-se uma comparação qualitativa entre o uso do inversor a dois níveis e do inversor a três níveis que mostra em que situações é conveniente utilizar o inversor a três níveis<br>Abstract: It is presented the implementation of a three phase three level voltage inverter to be used in the speed control of a three phase permanent magnet synchronous motor using the vector control method. To achieve this goal, it was carried out the study, design and construction of a three level neutral point clamped voltage inverter or NPC inverter. For the control of the motor it was used a space vector modulation. The proposed system was simulated using Matlab/Simulink and PSIM softwares. It was carried out an experimental assembly consisting of a 0.75 kW permanent magnet synchronous motor coupled to an electromagnetic brake as a mechanical load. The motor and load system were triggered by the inverter with space vector modulation. The results of the speed control, including reversal of speed and motor breaking, are presented in the study. The performance of a three level inverter using space vector modulation is compared to the performance of a two level inverter using space vector modulation feeding a resistive load. The simulation and experimental results are presented. In this work a qualitative comparison between the two level inverter and three level inverter was done showing in wich situations it is better to use the three level inverter<br>Mestrado<br>Energia Eletrica<br>Mestre em Engenharia Elétrica
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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.
Full textAbstract:
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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Gléba, Gergely. "Implementace algoritmů řízení elektrických motorů v systémech CompactRIO." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220195.
Full textAbstract:
This master’s thesis deals with the implementation of existing algorithms of electric AC motor control in Matlab Simulink to LabVIEW Control Design and Simulation. The first part of the thesis treats with the deduction of a mathematical model of an asynchronous motor, permanent magnet synchronous motor and with the theory of vector control of AC motors. In the next part there is a brief guide to create simulation algorithms in LabVIEW environment and to create the model of a motor with EMI functions in language C. The last part contains the comparison of Matlab Simulink and LabVIEW simulation tools.
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Rabelo, joca Davi. "Une Topologie CA-CC Baseé sur un Convertisseur Modulaire Multiniveau Entrelacé Faisible à Applications de Transformateur d’Électronique de Puissance." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC010/document.
Full textAbstract:
Ce travail concerne l'étude théorique,l’analyse numérique et la validationexpérimentale d'une topologie de convertisseurd’électronique de puissance basée sur unconvertisseur multiniveau modulaire entrelacéavec transformateur moyenne fréquence.L’architecture est adaptée pour l’étage deconversion AC-DC dans les applications detransformateur d'électronique de puissance pourla connexion entre un réseau alternatif moyennetension et un réseau continu basse tension.L’entrelacement réduit les pertes par conductiondans les interrupteurs. Le transformateurmoyenne fréquence 10 kHz assure une isolationgalvanique et connecte le convertisseurmultiniveau modulaire entrelacé à unconvertisseur pont complet. Avec comme pointde départ la structure, le principe defonctionnement, la modélisation, la technique demodulation et le schéma de commande sontdiscutés. Une caractéristique du convertisseur estla génération simultanée de la tension du réseaubasse fréquence et de la tension primaire dutransformateur moyenne fréquence.L'équilibrage de la tension des condensateurs etla minimisation du courant de circulation sontcombinés dans un seul algorithme. La commanderégule le courant alternatif et la tension du buscontinu, du côté haute tension, ainsi que latension continue et le flux de puissance, du côtébasse tension. La validation expérimentale duconvertisseur est réalisée avec un prototype de720 W monophasé à l’échelle réduite. Lesrésultats démontrent la stabilité du système decommande lors d'opérations en régimepermanent et dynamiques (pas de charge,inversion du flux de puissance)<br>This work aims to present thetheoretical study, the numerical analysis and theexperimental validation of a power electronicsconverter topology based on an interleavedmodular multilevel converter with mediumfrequencytransformer. The architecture issuitable for the AC-DC stage in solid-statetransformer applications for the connectionbetween a medium-voltage AC grid and a lowvoltageDC grid. The interleaving reduces theswitch conduction losses. The 10 kHz mediumfrequencytransformer provides galvanicisolation and connects the interleaved modularmultilevel converter to a full-bridge converter.From the converter structure, the principle ofoperation, the modeling, the modulationtechnique, and the control scheme are discussed.One feature of the converter is the simultaneousgeneration of the low-frequency grid voltageand the medium-frequency transformer primaryvoltage. The capacitor voltage balancing and thecirculating currents minimization are combinedtogether in a single algorithm. The controlsystem regulates the AC current and the DC busvoltage, on the high-voltage side, and the DCvoltage and power flow, on the low voltage side.The experimental validation of the converter ismade with a scaled-down single-phase 720 Wprototype. The results demonstrate the controlsystem stability in steady-state and dynamic(load step, power flow inversion) operations
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Cuadros, Carlos Eduardo. "On the Circuit Oriented Average Large Signal Modeling of Power Converters and its Applications." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11077.
Full textAbstract:
A systematic and versatile method to derive accurate and efficient Circuit Oriented Large Signal Average Models (COLSAMs) that approximate the slow dynamics manifold of the moving average values of the relevant state variables for Pulse-Width Modulated (PWM) dc to dc and three-phase to dc power converters is developed. These COLSAMs can cover continuous conduction mode (CCM) as well as discontinuous conduction mode (DCM) of operation and they are over one order of magnitude cheaper, computation wise, than the switching models. This method leads primarily to simple and effective input-output oriented models that represent transfer as well as loading characteristics of the converter. Sine these models consist of time invariant continuous functions they can be linearized at an operating point in order to obtain small-signal transfer functions that approximate the dynamics of the original PWM system around an orbit.
The models are primarily intended for software circuit simulators (i.e. Spice derived types, Saber, Simplorer, etc), to take advantage of intrinsic features such as transient response, linearization, transfer function, harmonic distortion calculations, without having to change simulation environment. Nevertheless, any mathematics simulator for ordinary differential equations can be used with the set of equations obtained through application of Kirchoff's laws to the COLSAMs. Furthermore, the COLSAMs provide physical insight to help with power stage and control design, and they allow easy interconnection among themselves, as well as with switching models, for complete analysis at different scales (time, signal level, complexity; interconnectivity).
A new average model for the Zero-Voltage Switched Full-Bridge (ZVS-FB) PWM Converter is developed with the above method and its high accuracy is verified with simulations from a switching behavioral model for several circuit component values for both CCM and DCM.
Intrinsic positive damping effects and special delay characteristics created by an energy holding element in a saturable reactor-based Zero-Voltage Zero-Current Switched Full-Bridge (ZVZCS-FB) PWM converter are explained for the first time by a new average model. Its large signal predictions match very well those from switch model simulations whereas its small-signal predictions are verified with experimental results from 3.5 kW prototype modules. The latter are used in a multi-module converter to supply the DC power bus in and aircraft. The design of control loops for the converter is based on the new model and its linearization.
The ZVZCS-FB PWM converter's average model above is extended to deal with interconnection issues and constraints in a Quasi-Single Stage (QSS) Zero-Voltage Zero-Current Switched (ZVZCS) Three-Phase Buck Rectifier. The new model reveals strong nonlinear transfer characteristics for standard Space Vector Modulation (SVM), which lead to high input current distortion and output voltage ripple inadmissible in telecommunications applications. Physical insight provided by this average model led to the development of a combined modified SVM and feed-forward duty-cycle compensation scheme to reliably minimize the output voltage ripple. Experimental results from a 6 kW prototype validate large signal model for standard and modified SVM, with and without duty-cycle compensation scheme.<br>Ph. D.
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Pavan, Rayana Siva. "Study of Induction Motor Drive With Indirect Vector Control Using Space Vector Pulse Width Modulation." Thesis, 2017. http://ethesis.nitrkl.ac.in/8946/1/2017_MT_RSPavan.pdf.
Full textAbstract:
Induction motors are thee starting point to design an electrical drivee system which is widely used in many industrial applications. Inn modern control theory, different mathematical models describe induction motor according to thee employed control methods. Vector control strategy can bee applied to this electrical motor type inn symmetrical three phase version or in unsymmetrical two phase version. The operation of the induction motor can be analyzed similar to a DC motor through this control method. With the Joint progress of thee power electronics and numerical electronics it is possible today to deal with thee axis control with variable speed inn low power applications. With these technological projections, various command approaches have been developed by the scientific community to master inn real time, thee flux and thee torque of thee electrical machines, thee indirect vector control (IVC) scheme being one of the most recent steps in this direction. This scheme provides excellent properties of regulation without rotational speed feedback. Inn this control scheme thee electromagnetic torque and stator flux magnitude are estimated with only stator voltages and currents and this estimation does not depend on motor parameters except for thee stator resistance.
Inn this dissertation report conventional IVC scheme has been described. Induction motor has been simulated inn stationary d-q reference frame and its free acceleration characteristics are drawn. Conventional IVC scheme has been simulated with a 50 HP, 460V, 50Hz induction motor. Literature review has been done to study the recent improvements inn IVC scheme which somehow is abe to overcome the drawbacks of conventional one.
Thee space vector modulation technique (SVPWM) is applied to 2 level inverter control inn thee vector control based induction motor drivee system, thereby dramatically reducing thee torque ripple. Later inn this project space vector PWM technique will be applied to IVC drivee system to reduce thee torque ripple.
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Tzeng, Wei-Luen, and 曾威倫. "The research on the Space Vector Pulse Width Modulation Control IC." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/83011075255636066828.
Full textAbstract:
碩士<br>國立臺北科技大學<br>電機工程系碩士班<br>91<br>The main research of the thesis is based on Cell-based digital IC design flow, and use the TSMC 0.35um 1P4M cell library, to develop Space Vector Pulse Width Modulation（SVPWM）Control IC, and manufactured at S35_92C of the CIC’s advance chip.
First , use the Hardware Description Language（VHDL）to encoding the system function, then use the compiler to make sure the syntax of the HDL is correct , after the Synthesis tool and auto place & routed tool and function simulation tool, make sure that every step is right, the design flow of the space vector modulation is complete. Not only can simulate the IC’s function expect software, but also can use Filed Programmable Gate Array（FPGA）as well.
After complete the SVPWM control IC made use of Cell-based design flow, use the simulation tools, Modelsim and time-mill and power-mill, to simulate the RT level simulation and gate-level simulation and post-layout simulation of the control IC. We can find the conclusion in every level simulation, under the Cell-based IC Design flow, every function of the SVPWM control IC in this thesis, Sample rate control, Dead time control, Fundamental frequency control, Modulation control, and System Clock all correct. Then, use the FPGA to replace the design of SVPWM control IC , add the input signal control board made by myself , cooperated with the power driver and the induction motor of the three phase AC power, we can build a space vector modulation testing system. In the testing system, FPGA generates the control signal to drive the power driver successfully, and the power driver also makes the motor to rotate correctly.
Under such multilevel simulation of the software and hardware simulation reality, all the design of the space vector pulse width modulation control IC in this thesis can movement correctly. So, this thesis make a motor control IC design flow successfully. In the future, the research will make the motor close-loop control system into IC under the same design flow, and combine the analog circuit, then the motor control IC of mixed signal is done, and also complete the final objective of this thesis.
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Wu, Yu-Ren, and 巫毓仁. "A Study on Three-Level Inverter with Space Vector Modulation Methods." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/x48yz2.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>104<br>This thesis investigates the circuit topology of three-level T-Type inverters, and analyzes the principle of space vector modulation (SVM) method. Through the detailed study of three-level SVM, equivalent two-level SVM and the advanced bus-clamping methods, the performance of SVM in controlling the T-type inverter are analyzed, especially the advanced bus-clamping method in improving the output quality of the line current in the high modulation index is verified. MATLAB/Simulink software is adopted for the simulation. ALTERA’s software Quartus II is used to design the control module of space vector modulation method, and the code is downloaded to a FPGA development board (DE2-115) to generate twelve sets of control signal and then sent to a prototype circuit of MOSFET-based T-Type inverter for realization. The effectiveness of the T-Type inverter with SVM methods is verified by simulation and experiment results.
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Kuo, Wei-cheng, and 郭韋誠. "Direct torque control of induction motor drive using space vector modulation." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/83220186241000691731.
Full textAbstract:
碩士<br>正修科技大學<br>電機工程研究所<br>96<br>The advantage of the conventional direct torque control (DTC) method is that both torque and flux linkage can be controlled rapidly to get a better and faster speed response. Because of using only 8 fundamental voltage space-vectors, DTC easily induces the large ripple problems of the controlled torque and flux responses. Therefore, this thesis proposes a proportional-integral controller (PIC) for induction motor drive based on DTC and space-vector pulsewidth modulation, to solve these ripple problems. However, since PIC is sensitive to parameter uncertainties and load disturbances, a hybrid sliding mode controller (SMC), involving a flux SMC and speed SMC, is then provided to improve the robustness of the controlled system for the parameter uncertainties and load disturbances. Based on field-oriented control principle and space-vector modulation technology, a flux SMC is firstly developed to achieve fast direct flux control and a speed SMC is, then, presented to enhance speed control response by direct torque control approach. Finally, simulation results, compared among DTC, PIC and Hybrid SMC, verify that the proposed hybrid SMC can achieve a better robust control performance, even though under the influence of parameter variations, load disturbance etc.
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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.
Full textAbstract:
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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Yang, Ting Ou, and 歐陽霆. "A novel Space Vector Modulation strategy for quasi-Z-source inverters." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/6djxmw.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電機工程系<br>105<br>Quasi-Z-source inverter (qZSI) features high compactness, low component and thermal stresses, continuous input current and the capability of simultaneously carry out both DC voltage boost and DC-AC inversion. For qZSIs, sinusoidal pulse width modulation (SPWM) method is typically applied. Comparing with SPWM, space-vector PWM (SVPWM) has advantages such as low current harmonics and high voltage utilization; hence, the traditional space-vector concept has been modified to be applicable for the qZSI in the literatures.
In this thesis, a novel SVPWM strategy for qZSIs is presented. Instead of placing the shoot-through state in both inverter legs, the proposed method generates the shoot-through state only in left/right inverter leg during the positive/negative cycle, respectively. Using this way, the voltage distortion of the conventional SVPWM qZSI can be reduced. In order to validate the correctness of the proposed methods, a single-phase 110 Vac, 60 Hz, 350 W prototyping circuit is built. According to the experimental results, the measured conversion efficiencies of the designed system are all higher than 93.95 %. Comparing with the conventional qZSI using SVPWM control, the proposed modulation technique can improve the averaged conversion efficiency and voltage distortion by 0.482% and 1.125 %, respectively.
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Babu, Amarlapudi Mahesh. "Direct Torque Control of BLDC Motor Using Space Vector Modulation Technique." Thesis, 2017. http://ethesis.nitrkl.ac.in/8915/1/2017_MT_AMBabu.pdf.
Full textAbstract:
Brushless DC Motors are used because of their higher efficiency, easy maintenance and high torque to inertia ratio. Several methods were proposed for better control of torque and current. Almost all the proposed techniques are complex and stator flux control is not considered in this technique due to this high-speed operations are not possible. The sensorless technique implemented is similar to Direct Torque control Technique for AC Motors This method controls torque directly and stator flux indirectly. The electric rotor position of the motor can be determined by using winding inductance, stator fluxes and currents of the stationary reference frame. Pulse Width Modulation Techniques are used to control the output voltage and frequency of the voltage source inverter.SV- PWM technique is preferred because it reduces switching losses, harmonic distortion, better utilization of available DC bus voltages.
In This Thesis Space Vector PWM Technique allows the regulation of varying signals than that of Pulse Width and vector control techniques. This Thesis provides the model for sensorless Direct Torque Control of BLDC motor drive with SV-PWM Technique using MATLAB/Simulink.
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Kumar, Amit. "Improved Direct Torque Control of Induction Motor With Space Vector Modulation." Thesis, 2017. http://ethesis.nitrkl.ac.in/8923/1/2017_MT_AmitKumar.pdf.
Full textAbstract:
The Direct Torque Control (DTC) is a type of vector control technique which is used to regulate the torque and hence speed of an induction motor drive. This method is very efficient, cheap and is very easy to execute. The absence of mechanical speed estimators along with the ease of processing and computations make it the most preferred option among all vector control techniques. In this method, only the voltage and current are sensed and they are used to estimate the torque, flux and the angle between the rotor and stator flux. Depending on the torque and flux errors, a suitable voltage vector is selected to keep the errors within the desired tolerance region. At present times, three phase induction motors have become the backbone of industries. Lifts, agricultural pumps, conveyor belts, lathes, cranes, drilling machine, etc. are some of the prominent areas where induction motors have been very effective. These motors can be controlled using the scalar V/F control techniques. However, for applications requiring quick response vector control techniques like DTC are preferred. But the problem lies in the presence of torque ripples in case of DTC of three phase induction motor drive. The study is done by simulation using the MATLAB/Simulink Power System Block set that allows a complete representation of the power section (inverter and induction motor) and the control system. The performance of the two control schemes i.e a conventional DTC method and space vector modulation DTC is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command, and emphasizing advantages and disadvantages. A comparative study between both the method has been carried out.
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Huang, Hsien-Ching, and 黃献清. "Research of Space Vector Pulse Width Modulation Method for the Matrix Converter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4kah8s.
Full textAbstract:
碩士<br>中華大學<br>電機工程學系<br>107<br>This study is use the Space Vector Pulse Width Modulation Method for the Matrix Converter, the relationship between the input current and the output voltage at each output frequency and amplitude modulation is analyzed in detail under the space vector pulse width modulation method.
Compare the output efficiency and total harmonic distortion (THD) of the input current and the output voltage, on the matrix converter at 120∘switching mode and 180∘switching mode.
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Vafakhah, Behzad. "Multilevel Space Vector PWM for Multilevel Coupled Inductor Inverters." Phd thesis, 2010. http://hdl.handle.net/10048/1023.
Full textAbstract:
A multilevel Space Vector PWM (SVPWM) technique is developed for a 3-level 3-phase PWM Voltage Source Inverter using a 3-phase coupled inductor to ensure high performance operation. The selection of a suitable PWM switching scheme for the Coupled Inductor Inverter (CII) topology should be based on the dual requirements for a high-quality multilevel PWM output voltage together with the need to minimize high frequency currents and associated losses in the coupled inductor and the inverter switches.
Compared to carrier-based multilevel PWM schemes, the space vector techniques provide a wider variety of choices of the available switching states and sequences. The precise identification of pulse placements in the SVPWM method is used to improve the CII performance. The successful operation of the CII topology over the full modulation range relies on selecting switching states where the coupled inductor presents a low winding current ripple and a high effective inductance between the upper and lower switches in each inverter leg. In addition to these requirements, the CII operation is affected by the imbalance inductor common mode dc current. When used efficiently, SVPWM allows for an appropriate balance between the need to properly manage the inductor winding currents and to achieve harmonic performance gains.
A number of SVPWM strategies are developed, and suitable switching states are selected for these methods. Employing the interleaved PWM technique by using overlapping switching states, the interleaved Discontinuous SVPWM (DSVPWM) method, compared to other proposed SVPWM methods, doubles the effective switching frequency of the inverter outputs and, as a result, offers superior performance for the CII topology by reducing the inductor losses and switching losses.
The inverter operation is examined by means of simulation and experimental testing. The experimental performance comparison is obtained for different PWM switching patterns. The inverter performance is affected by high-frequency inductor current ripple; the excessive inductor losses are reduced by the DSVPWM method. Additional experimental test results are carried out to obtain the inverter performance as a variable frequency drive when operated in steady-state and during transient conditions. The CII topology is shown to have great potential for variable speed drives.<br>Power Engineering and Power Electronics
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Li, Chien-Hsinh, and 李建興. "Implementation of Space-Vector Pulse-Width-Modulation Inverter for Three-Phase Induction Motors." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/54609099884431307244.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程技術研究所<br>87<br>This thesis discusses the design and implementation of the three phase induction motor drive system using a space-vector pulse-width-modulation (SVPWM) strategy based on a voltage-source inverter(VSI). A variable frequency, variable voltage converter is applied for the system control in induction motors.
This thesis is separated in two sections. First section introduces the implementation of IGBT protection circuit. A gate voltage controlled protection circuit is proposed to cut off the high fault current within short-circuit withstand time(nearly 10 us). The proposed protection circuit features a simple circuit and no extra DC power supply, and provides good protection characteristics.
A digital control inverter for a three-phase induction motor is discussed in the second section. The inverter with voltage/frequency (V/F) control was developed and implemented on a TMS320F240 DSP-based platform. The SVPWM strategy is applied for the control of inverter to reduce the voltage and current harmonics in the inverter output and consequently provide a smooth operation of the induction motor. The proposed SVPWM algorithm is discussed. Results of analytical and experimental investigation provide a guideline for the design and improvement of V/F control method used in induction motor drives.
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H, Tsai K., and 蔡坤隍. "The Space Vector Pulse Width Modulation Based of Synchronous Reluctance Motor Speed control." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/11349226861501050250.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程技術研究所<br>86<br>The synchronous reluctance motor(SRM) has the simple structure, easy controllability, no slip, and rotor without permanent magnets which has the advantages both of induction motor and brushless motor. Under the rising growth of power electron and powerful calculation of microprocessors, the AC motors have increasingly disentangled from the conventional analog controller, and develop toward the half-digital or full-digital controller. This thesis proposes a DSP based, variable speed system of synchronous reluctance motor. First, the construction,
characteristics, mathematical model, and the nowaday control strategies of
synchronous reluctance motor are studied. Second, a three phase inverter and their peripheral control circuit are finished. The space vector pulse width modulation method was applied. For improving the SRM low torque flaw, the maximum torque strategies was adopted. Finally, a quasilinear fuzzy control strategy is introdud to investigate the try and error spot of conventional speed controller and to improve transient response performance of whole closed system.
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Saeedifard, Maryam. "Space Vector Modulation of Multi-level and Multi-module Converters for High Power Applications." Thesis, 2008. http://hdl.handle.net/1807/17261.
Full textAbstract:
This thesis presents and investigates Space Vector Modulation (SVM) switching strategies for (i) a multi-level Diode-Clamped Converter (DCC) and (ii) a multi-module Voltage-Sourced Converter (VSC) system in which each module is a conventional two-level VSC. Although the SVM strategies are general and applicable for n-level DCC and n-module VSC systems, this text only concentrates on five-level DCC and four-module VSC systems.
For a five-level DCC, a computationally efficient SVM algorithm is proposed. The algorithm, that is based on a classifier Neural Network (NN), reduces the computational time for the SVM realization. Therefore, adequate saving of processor execution time, in each sampling period of SVM, is provided to carry out other functions, e.g. the calculations required for DC-capacitor voltage balancing task. The thesis also proposes a DC-capacitor voltage
balancing strategy to counteract the voltage drift phenomenon of (i) a passive-front-end five-level DCC, and (ii) a back-to-back
connected five-level DCC system. The proposed balancing strategy, that is based on augmenting the proposed SVM algorithm, takes advantage of the redundant switching states to minimize a quadratic cost function associated with voltage deviations of the
DC-capacitors. The salient features of the proposed balancing strategy are (i) online calculation of SVM to select the best
switching states, (ii) minimization of switching frequency, (iii) minimization of the THD content of the AC-side voltage, and (iv) no requirement for additional power circuitry.
For a four-module VSC system a sequential sampling SVM strategy is proposed. The proposed strategy (i) provides harmonic cancellation/minimization at the net AC-side voltage of the multi-module VSC system, and (ii) offers a low switching frequency
for each VSC module.
Technical feasibility of the proposed SVM strategies for a five-level DCC and a four-module VSC system, as a STATCOM and a
back-to-back HVDC system, are investigated and presented. The studies are conducted in the time-domain, in the PSCAD/EMTDC
software environment.
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Chou, Jung-Ching, and 周榮慶. "Design and Implementation of Direct Torque Control with Voltage Space Vector Modulation on FPGA." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/zn277h.
Full textAbstract:
碩士<br>國立臺北科技大學<br>電機工程系研究所<br>98<br>The thesis is to design a direct torque control (DTC) system using vlotage space vector modulation (VSVM) method to decrease the ripple of torque and flux. Verilog hareware description language (HDL) is used to completed the hardware architecture. Finally, this system is implemented and verified on FPGA.
The basic principle of this control system is to calculate the stator’s magnetism flux and torque by detecting the three-phase current, three-phase voltage and the rotor speed. By using the torque PI controller, magnetism flux PI controller, and coordinate transform circuit, we can have a suitable voltage space vector to switch power MOSFET of inverter, and have a stable response in motor speed. Notify that the formula calculation is used to decide the reference voltage instead of voltage vector switch table. It fully takes the advantage of digital IC which has fast operation speed.
After confirming the syntax and function of source code, the control system need to be verified with QuartusII and ModelSim. Finally, we verify the function of this control system by Alteta’s EP2C70F896C6 FPGA IC and complete this three-phase induction motor control system design.
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Liu, Kuo-Hsien, and 劉國賢. "Analysis and Implementation of a Novel Optimized Space Vector Modulation Strategy for Multilevel Inverter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/49819057712954708632.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>95<br>Multilevel inverters have been widely used in the high power applications and various multilevel modulation strategies are developing gradually. Among them, space vector pulse width modulation (SVPWM) has better performance, high degree of design freedom and complicated modulation process. Implementation of the SVPWM for multilevel inverter is complicated, tedious and calculation numerously. This is due to the difficulty in determining the location of reference voltage , the calculation for each vector’s dwelling time numerously, and as the number of levels increases, redundant switching states and complicated choice in determining the switching sequence increase dramatically and brings difficulty in selecting switching state and determining switching sequence.
Due to the complexity of realization, this thesis presents a novel space vector modulation strategy for the multilevel inverter. n level inverter is equivalent to n-1 two-level inverters by the concept of the equivalent inverter. Since the redistribution of the space vector plane and the establishment of vector decomposition rules, space vector plane and reference voltage will be simplified to n-1 two-level planes and n-1 two-level reference voltages for resynthesize the original reference voltage and controlling n-1 equivalent two-level inverters. Therefore, the multilevel SVPWM with high complexity can be finished briefly by the two-level SVPWM method. Comparing with the conventional nearest three vector approach, this strategy is easy to realize without complex calculation. Besides, this modulation strategy certainly achieve the optimized switching sequence with the only selection way of determine switching sequence. Simulations and experiments will verify its validity and the realization of all functions uses TI Company’s TMS320LF2407A digit signal processor to implement the digital control of whole system.
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Zhang, You-Cheng, and 張祐誠. "Simulation and Implementation of Three Level Z-Source Inverters with Space Vector Modulation Method." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/61734789392372615346.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>103<br>The Z-source inverter employs a unique impedance network and shoot through state to achieve boost voltage that overcome the limitations of the traditional voltage-source inverter. This thesis investigates the space vector modulation method for three-level Z-source inverters. Through the detailed study of shoot through state design and adopt an optimized switching sequence arrangement, this gives the benefit of without extra switching loss and lower output harmonic distortion. The proposed technique is demonstrated in simulation results from MATLAB/ Simulink/SimPowerSystems. Then, the ALTERA Quartus II software is used for constructing the control module of three level space vector modulation, and download the program to FPGA development board. A MOSFET-based three level Z-source inverter is implemented and verified the feasibility.
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Yeh, Ming-Yang, and 葉名揚. "Research of the Space Vector Modulation Technique for the Four-Pole Voltage Source Converter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/56517013342229135520.
Full textAbstract:
碩士<br>國立清華大學<br>電機工程學系<br>99<br>In the three phase four wire system, when systems are the unbalance load, it will cause the problems of zero sequence current and voltage. In order to improve this condition, the conventional method is to separate the DC-link capacitor, and inject the zero sequence current into the midpoint of the capacitor. However, this method will need the larger capacitor to eliminate the ripple of capacitor, and even worse, will reduce the lifetime of capacitor because of the effect of zero sequence current. Base on the above problems, this thesis proposes the method for a four-pole converter to eliminate the problems of zero sequence current which is caused by the unbalanced load of the system. The four-pole converter adopts three dimensional space vector modulation to control the positive sequence, negative sequence and zero sequence voltage. Based on the proposed method, the whole system can have more operational choices and increase reliability when facing problems of unbalancing loading, to maintain the quality of the output voltage.
This thesis will introduce the control method of three dimensional space vector modulation and explain how to use space vector selection to construct voltage command of the four-pole converter in different operation states. In different unbalanced conditions, the four-pole converter will be introduced to control the zero sequence current, and maintain the system operation. In the end of the report, the simulation and experimental result will also be included to verify the zero sequence voltage elimination method.
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Kumar, Vudatha Vinod. "Analysis of Induction Motor Drive With Direct Torque Control Scheme Using Space Vector Modulation." Thesis, 2015. http://ethesis.nitrkl.ac.in/7642/1/96.pdf.
Full textAbstract:
Direct torque control (DTC) is one in all the foremost wonderful management methods of torque control of the induction motor. The aim is to regulate effectively the torque and flux. Torque control of associate induction motor (IM) supported DTC strategy is a developed and a comprehensive study which is made during this project. Direct torque management is that the 1st technology to regulate the important control variables of torque and flux. This methodology makes the rotor more accurate and quick management, high dynamic speed response and easy to regulate. The reference value may be calculated by the flux and torsion estimation and conjointly motor parameters. With the joint progress of numerical electronics and power electronics, it's potential nowadays to subsume the axis management with variable speed in applications involving low power. With these projections of technology, various command approaches are developed by the scientists to master in real time, the torque and also the flux of the electrical ac machines, the direct torque control (DTC) theme being one in all the foremost recent steps during this direction. This theme provides excellent regulation properties without using rotational speed feedback. During this control theme the electro- magnetic torque and mechanical device (stator) flux magnitude are calculable with solely mechanical device voltages and currents and this estimation doesn't rely upon motor parameters apart from the mechanical device (stator) resistance. In this thesis, typical DTC theme has been delineated. The induction motor (IM) has been simulated in stationary d-q arrangement and its free running acceleration characteristics are drawn. Typical DTC theme has been simulated with a two hundred horse power (200 HP), 460V, 60Hz induction motor. The literature review has been done to review the latest advancements in DTC theme that in someway is ready to beat the drawbacks of the typical one. The space vector modulation technique (SVM) is applied during this project to two level electrical converter (inverter) within the direct torque management primarily based on induction motor drive system. Space vector PWM methodology may be applied as future work to DTC drive system to cut back the torque (torsion) ripple.
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Myna, Bandi. "Direct Power Control of Three-Phase PWM Rectifier using Space- Vector Modulation (DPC- SVM)." Thesis, 2017. http://ethesis.nitrkl.ac.in/8914/1/2017_MT_BMyna.pdf.
Full textAbstract:
This work provides a control strategy for PWM rectifiers using space vector modulation technique by keeping the switching frequency as constant. Instead of using line currents as control variables here instantaneous active and reactive power are used as signals for modulation of PWM rectifiers. In traditional control methods like VDPC and VFDPC, we are having line voltage estimator and virtual flux estimator. Here virtual flux estimator and line voltage estimator are replaced with Phase Locked Loop for better performance in distorted conditions at source side. The strategy of direct power control using space vector modulation is discussed theoretically. The steady state results are presented for the proposed DPC – SVM system. Compared to other control strategies the DPC-SVM have special features like constant switching frequency, unity power factor by providing distortion less sine wave as current under unbalanced conditions.
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Hari, V. S. S. Pavan Kumar. "Comparative Evaluation Of Space Vector Based Pulse Width Modulation Techniques In Terms Of Harmonic Distortion And Switching Loss." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/868.
Full textAbstract:
Voltage source inverters (VSI) are popular in variable speed induction motor drive applications. Pulse width modulation (PWM) is employed to achieve variable voltage variable frequency output from a fixed DC bus voltage. The modulation method greatly influences the harmonic distortion in line current and the inverter switching loss. This thesis evaluates a few space vectorbased PWM techniques which reduce the harmonic distortion and/or the inverter switching loss, compared to conventional space vector PWM (CSVPWM), at a given average switching frequency.
In space vector-based PWM, the average voltage vector applied over a sub-cycle equals the commanded reference vector, thereby maintaining voltsecond balance. The given average vector can be realized by applying the voltage vectors of the inverter in different sequences. CSVPWM employs a switching sequence in which all the phases switch once in a sub-cycle. Sequences, in which a phase is clamped, while the other two phases switch once in a sub-cycle have been reported in literature. Further, certain special switching sequences have also been reported recently. These special sequences involve switching a phase twice, while switching the second phase once and clamping the third phase in a sub-cycle. This work investigates the use of such special switching sequences to reduce line current distortion and inverter switching loss in an induction motor drive.
The influence of various switching sequences on line current ripple and inverter switching loss is discussed in the thesis. Comparison of the sequences in terms of switching loss leads to a hybrid PWM technique, which deploys the best sequence to reduce switching loss under a given operating condition. This technique is referred to as minimum switching loss PWM (MSLPWM). Further, a procedure for design of hybrid PWM techniques to achieve reduced line current distortion as well as inverter switching loss is elaborated. Four such specially designed hybrid PWM techniques are discussed.
Analytical methods are presented for the evaluation of total RMS harmonic distortion factor of line current and inverter switching loss corresponding to different PWM techniques. The MSLPWM and the hybrid PWM techniques are evaluated analytically in terms of harmonic distortion and switching loss. It is observed that the switching loss corresponding to MSLPWM is considerably less than that with CSVPWM over the entire range of power factor. The reduction in switching loss with MSLPWM is as high as 36% at high power factors close to unity, while it is not less than 22% at power factors close to zero. MSLPWM also reduces the harmonic distortion for power factors close to unity at high modulation indices. Compared to CSVPWM, the hybrid PWM techniques result in a maximum reduction of about 40% in the harmonic distortion at fundamental frequencies close to 50Hz, and about 30% reduction in switching loss at power factors close to unity.
The various PWM techniques are tested on a constant V /f induction motor drive with a digital control platform based on ALTERA Cyclone II field programmable gate array (FPGA) device. With a 10kVA IGBT based inverter feeding a 2.2kW, 415V, 50Hz, three-phase induction motor, the total RMS harmonic distortion factor of line current (IT HD) is measured at different fundamental frequencies for the various PWM techniques. The average switching frequency is 2.44kHz. The measured values of IT HD show a reduction in distortion with the hybrid PWM techniques over CSVPWM at high speeds of the drive. The relative values of IT HD corresponding to different PWM techniques agree with the theoretical predictions.
With the 10kVA IGBT based inverter feeding a 6kW, 400V, 50Hz, 4pole, three-phase induction motor, the switching losses corresponding to CSVPWM and MSLPWM are evaluated and compared. This is done by measuring the steady state temperature rise of the heat sink over the ambient for the two techniques under different conditions. The thermal measurements are carried out at different loads with power factor ranging from 0.14 to 0.77. The measurements are also carried out at different fundamental frequencies (or modulation indices). Further, to separate conduction (constant) losses and switching (variable) losses, the heat sink temperatures are measured at two different switching frequencies, namely 2.44kHz and 4.88kHz. It is observed that the temperature rise due to MSLPWM is less than that due to CSVPWM consistently under various operating conditions. The thermal measurements confirm the theoretical prediction of reduction in switching loss with MSLPWM.
Measurements of heat sink temperature rise corresponding to CSVPWM, MSLPWM and the hybrid PWM techniques are carried out at a higher power factor of 0.98 (lag) with the inverter feeding an RL load (instead of an induction motor). The hybrid PWM and
MSLPWM result in lower switching losses as indicated by the reduction in temperature rise.
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Hari, V. S. S. Pavan Kumar. "Comparative Evaluation Of Space Vector Based Pulse Width Modulation Techniques In Terms Of Harmonic Distortion And Switching Loss." Thesis, 2008. http://hdl.handle.net/2005/868.
Full textAbstract:
Voltage source inverters (VSI) are popular in variable speed induction motor drive applications. Pulse width modulation (PWM) is employed to achieve variable voltage variable frequency output from a fixed DC bus voltage. The modulation method greatly influences the harmonic distortion in line current and the inverter switching loss. This thesis evaluates a few space vectorbased PWM techniques which reduce the harmonic distortion and/or the inverter switching loss, compared to conventional space vector PWM (CSVPWM), at a given average switching frequency.
In space vector-based PWM, the average voltage vector applied over a sub-cycle equals the commanded reference vector, thereby maintaining voltsecond balance. The given average vector can be realized by applying the voltage vectors of the inverter in different sequences. CSVPWM employs a switching sequence in which all the phases switch once in a sub-cycle. Sequences, in which a phase is clamped, while the other two phases switch once in a sub-cycle have been reported in literature. Further, certain special switching sequences have also been reported recently. These special sequences involve switching a phase twice, while switching the second phase once and clamping the third phase in a sub-cycle. This work investigates the use of such special switching sequences to reduce line current distortion and inverter switching loss in an induction motor drive.
The influence of various switching sequences on line current ripple and inverter switching loss is discussed in the thesis. Comparison of the sequences in terms of switching loss leads to a hybrid PWM technique, which deploys the best sequence to reduce switching loss under a given operating condition. This technique is referred to as minimum switching loss PWM (MSLPWM). Further, a procedure for design of hybrid PWM techniques to achieve reduced line current distortion as well as inverter switching loss is elaborated. Four such specially designed hybrid PWM techniques are discussed.
Analytical methods are presented for the evaluation of total RMS harmonic distortion factor of line current and inverter switching loss corresponding to different PWM techniques. The MSLPWM and the hybrid PWM techniques are evaluated analytically in terms of harmonic distortion and switching loss. It is observed that the switching loss corresponding to MSLPWM is considerably less than that with CSVPWM over the entire range of power factor. The reduction in switching loss with MSLPWM is as high as 36% at high power factors close to unity, while it is not less than 22% at power factors close to zero. MSLPWM also reduces the harmonic distortion for power factors close to unity at high modulation indices. Compared to CSVPWM, the hybrid PWM techniques result in a maximum reduction of about 40% in the harmonic distortion at fundamental frequencies close to 50Hz, and about 30% reduction in switching loss at power factors close to unity.
The various PWM techniques are tested on a constant V /f induction motor drive with a digital control platform based on ALTERA Cyclone II field programmable gate array (FPGA) device. With a 10kVA IGBT based inverter feeding a 2.2kW, 415V, 50Hz, three-phase induction motor, the total RMS harmonic distortion factor of line current (IT HD) is measured at different fundamental frequencies for the various PWM techniques. The average switching frequency is 2.44kHz. The measured values of IT HD show a reduction in distortion with the hybrid PWM techniques over CSVPWM at high speeds of the drive. The relative values of IT HD corresponding to different PWM techniques agree with the theoretical predictions.
With the 10kVA IGBT based inverter feeding a 6kW, 400V, 50Hz, 4pole, three-phase induction motor, the switching losses corresponding to CSVPWM and MSLPWM are evaluated and compared. This is done by measuring the steady state temperature rise of the heat sink over the ambient for the two techniques under different conditions. The thermal measurements are carried out at different loads with power factor ranging from 0.14 to 0.77. The measurements are also carried out at different fundamental frequencies (or modulation indices). Further, to separate conduction (constant) losses and switching (variable) losses, the heat sink temperatures are measured at two different switching frequencies, namely 2.44kHz and 4.88kHz. It is observed that the temperature rise due to MSLPWM is less than that due to CSVPWM consistently under various operating conditions. The thermal measurements confirm the theoretical prediction of reduction in switching loss with MSLPWM.
Measurements of heat sink temperature rise corresponding to CSVPWM, MSLPWM and the hybrid PWM techniques are carried out at a higher power factor of 0.98 (lag) with the inverter feeding an RL load (instead of an induction motor). The hybrid PWM and
MSLPWM result in lower switching losses as indicated by the reduction in temperature rise.
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Wei, Zuo-Ying, and 魏佐穎. "Design and Implementation of a Sensorless IPMSM Drive System Using Space Vector Modulation Compensation Method." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4jpwcq.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電機工程系<br>107<br>This thesis investigates the rotor position/speed estimation using space-vector modulation compensation method and the predictive speed-loop controller design for interior permanent magnet synchronous motor drive systems. By computing the three-phase current slopes, the rotor position and speed of the motor can be estimated. The duty cycles of the active vectors could be too small; as a result, it is impossible to obtain the current-slopes of the active vectors when the motor is operated at standstill or low-speed operating region. An extension and compensation of three-level space-vector pulse width modulation method is proposed here. By using this method, the duty cycle of the active voltage vector is increased and the current harmonics are not obviously increased. The experimental results show that the current-slope computing method can be employed to estimate the rotor position/speed to improve the performance of the traditional hysteresis current control method, which causes too much current harmonics.
To improve the transient response, tracking ability and load disturbance rejection capability, the predictive speed-loop controller is used for the sensorless IPMSM drive systems. An predictive optimal control input is derived by using the performance index for the whole drive system.
A digital signal processor, TMS-320F-2808 is used as a control center to execute the control and estimation algorithms. Experimental results show the correctness and feasibility of the proposed methods.