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1
Gebreel, Abd Almula G. M. "Simulation and Implementation of Two-Level and Three-Level Inverters by MATLAB and RT-LAB." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1296051853.
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Floten, Sveinung, and Tor Stian Haug. "Modulation Methods for Neutral-Point-Clamped Three-Level Inverter." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10882.
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Multilevel converters have seen an increasing popularity in the last years for medium- and high-voltage applications. The most popular has been the three-level neutral clamped converter and still research is going on to improve the control of it. This master thesis was a continuation of the specialization project fall 2009. The main topics of current thesis were to further investigate the DC-bus balancing issues, compare symmetrical (one sampling per triangular wave) and asymmetrical (sampling at the top and bottom of the triangular wave) modulation, derive current equations for Space Vector and Double-Signal, improve output voltage in overmodulation and be able to DC-bus balance, and to implement the methods in the laboratory. Models of the three-level converter were made in the specialization project in both PSCAD and SIMULINK and further studies of the DC-bus balance were also made in this master thesis. None of the methods showed problems to regulate the DC-bus voltage when there was different capacitor values and unsymmetrical load. A PI controller was introduced for Space Vector but it did not show better performance than a regular P regulator. Asymmetrical modulation showed a clearly better performance than symmetrical modulation when the switching frequency was low compared to the fundamental frequency, especially for Space Vector. The 1st harmonic line-to-line voltage was closer to the wanted value and the THDi was significantly lower. Simulations also showed that the THDi can vary significantly depending on at which angle the first sampling is done. This is most clear for asymmetrical Space Vector modulation, but also for the other cases this pattern occurs. By implementing an overmodulation algorithm the amplitude of the 1st harmonic output voltage was closer to what was desired. Simulations showed how important it was to have three phase sampling symmetry in overmodulation. By having a wrong switching frequency the line-to-line output voltage dropped down to 2.06 when operating in six-step, when the wanted output value should be 2.205. Hence there is a quite large mismatch and the converter is sensitive to the switching frequency when it is operating in the higher modulation area. The balancing algorithm introduced for overmodulation is able to remove an initial offset without a notable change the 1st harmonic output. Both Space Vector and Double-Signal were tested in the laboratory with two separated DC-sources. Asymmetrical and Symmetrical modulation were tested and so was also overmodulation. The laboratory results confirmed the simulated results, but since the switching was not synchronized in the laboratory, some errors occurred.
3
Li, Xiaoming. "Design of a three-level inverter for an electric vehicle." Thesis, University of Canterbury. Electrical and Electronic Engineering, 1999. http://hdl.handle.net/10092/2220.
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A conventional two-level BIT inverter was installed in an electric vehicle to
control two AC induction motors at the University of Canterbury. Nowadays, power
device technology has made tremendous progress, and the IGBT becomes the best device
in high-quality drive system with inverters in the mid power range. A new three-phase,
three-level IGBT inverter has been design and will replace the conventional inverter for
the electric vehicle. This inverter produces an output voltage waveform which has three
difference levels and can generate a more sinusoidal shape than that of convention
two-level inverters. The output voltage of a three-level inverter contains less harmonics
than that of a conventional inverter.
This thesis deals with the development and implementation of a three-phase,
three-level IGBT inverter for an electric vehicle. The inverter design incorporated a
laminated busbar structure to reduce stray inductance. An IGBT gate drive circuit with
two-stage protection in the inverter is developed. To improve the efficiency and
reliability of the inverter, the gate drive provides high speed switching with attention to
di/dt and dv/dt requirements and controlled two-stage fault protection.
Computer Simulations are performed to demonstrate the operation of a three-level
inverter and to determine its specifications. Experimental tests are carried out to evaluate
the performance of the three-level inverter as an AC induction motor speed controller.
The inverter is tested on a motor load at full voltage, and maximum rated current and
torque. Simulation and experimental results show that in principle a three-level inverter is
suitable for the propulsion system of an electric vehicle.
4
Engku, Ariff E. A. R. B. "Space vector Pwm techniques for six-phase three-level inverter-fed drives." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/7982/.
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In recent years, research in the area of multiphase drives has increased significantly. Having higher number of machine phases allows the current to be shared between the phases, thus reducing the current rating of power semiconductors used in the power converter. Additionally, if a multilevel inverter is used to drive the machine, the output voltage waveforms are going to be approximated closer toward sinusoidal waveforms, thus resulting in lower total harmonic distortion. Therefore, the combination of multiphase and multilevel technologies gives considerable benefits compared to conventional two-level three-phase drives. Unlike a carrier-based approach, which can be easily expanded to any number of converter voltage levels and any number of machine phases, the development of space vector algorithms is also reliant on the machine’s configuration. In other words, different drive topologies require their own unique space vector algorithms. In fact, the complexity of developing a space vector algorithm will dramatically increase with the increase of number of levels and/or number of phases. This thesis presents pulse width modulation techniques for two- and three-level asymmetrical and symmetrical six-phase drives with a single or two isolated neutral points configuration. However, since the modulation techniques for the drives with two isolated neutral points are based on the well-established modulation techniques for three-phase drives, more emphasis is given towards the development of modulation techniques for single neutral point case, particularly those that are based on space vector algorithm principles. In order to realise sinusoidal output phase voltage waveforms, several requirements and conditions have to be met. The requirements revolve around ensuring that the low order harmonics, which contribute to the machine losses, will not exist. Meanwhile, the conditions are more towards minimising the switching losses. All modulation techniques are verified through simulation, while those for three-level case are validated experimentally as well. Comparison and discussion of obtained simulation and experimental results, performance and complexity in terms of execution time of the developed modulation techniques, are presented. The equivalence between corresponding modulation techniques, which are based on the space vector algorithm and carrier-based approach are also established.
5
Ayhan, Ufuk. "Investigation Of Dc Bus Current Harmonics In Two And Three Level Three-phase Inverters." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614182/index.pdf.
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Within scope of this work, double-fourier analysis method of rapid calculation and
detailed simulation method, which are used to investigate DC bus current harmonics
in two level and three level three-phase inverters systematically, will be emphasized
and two methods will be compared via applying different modulation techniques. In
addition, DC bus currents will be investigated visually for various working
conditions and modulation methods. After that, analysis methods will be applied
and harmonic spectrums will be determined. After all, it will be showed that
calculated harmonic spectrums could be treated as unified harmonics around certain
frequencies and these unified harmonics could be reached easily via looking at
predetermined table. Moreover, it will also be showed that unified harmonic values
could be used to determine harmonic current components that are necessary for
sizing DC bus capacitor and could be used in various inverter analysis.
6
Schrock, Kenneth C. "A three-level buck converter to regulate a high-voltage DC-to-AC inverter." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46505.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (leaves 94-95).
A three-level buck converter is designed and analyzed, and shown to be suitable as a high-voltage down converter as a pre-regulation stage for a 600 watt DC-to-AC power inverter. Topology selection for the inverter is examined, and a three-stage system is chosen to satisfy high voltage (1.1 kV), isolation, size, and efficiency requirements. Control of the buck converter is discussed in detail, including advanced features that allow extremely low output voltages in unloaded conditions. Optimization is included for both magnetics and switching losses. A prototype of the three-level buck converter is shown to perform as expected and meet all specifications.
by Kenneth C. Schrock.
M.Eng.
7
Mese, Huseyin. "Field Oriented Control Of Permanent Magnet Synchronous Motors Using Three-level Neutral-point-clamped Inverter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614407/index.pdf.
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In this thesis, field oriented control of permanent magnet synchronous motors using three-level neutral-point-clamped inverter is studied. Permanent magnet synchronous motors are used in high performance drive applications. In this study, the permanent magnet synchronous motor is fed by three-level neutral-point-clamped inverter. For three-level neutral-point-clamped inverter different space vector modulation algorithms, which are reported in literature, are analyzed and compared via computer simulations. The voltage balance on dc-link capacitors is also analyzed and a software control method is implemented in conjunction with the space vector PWM modulation, utilized. Nonlinear effects such as dead-time, semiconductor voltage drop and delays in gate drive circuitries also present in neutral-point-clamped inverter. The effects of these nonlinearities are studied and a compensation method for these nonlinear effects is proposed. The theoretical results are supported with computer simulations and verified with experimental results.
8
Trounce, Jonathan Charles. "Implementation of a direct torque controller using a three-level inverter for an electric vehicle application." Thesis, University of Canterbury. Department of Electrical and Electronic Engineering, 2001. http://hdl.handle.net/10092/2278.
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The University of Canterbury has been involved in the research and development of
electric vehicles since 1974. These electric vehicles use induction motors that are
designed with a low inductance such that they can run at high speed and therefore have a
high power to weight ratio. The inverter switching can cause high current ripple due to
the low inductance of these motors. A three-level inverter has been previously developed
for electric vehicle applications that produces an improved voltage waveform and
therefore has reduced current distortion.
This thesis describes the development of an induction motor torque controller for a three-level
inverter in an electric vehicle application. Four different induction motor torque
control schemes are considered. These are field oriented control, direct torque control
(DTC), minimal torque ripple DTC, and DTC using space vector modulation. All four of
the control schemes are simulated using MATLAB and Simulink, and DTC using space
vector modulation is chosen based on the simulation results. DTC using space vector
modulation is shown to have the low steady-state torque ripple, flux ripple, and current
distortion that is characteristic of space vector modulation and the fast transient
performance that is characteristic of direct torque control. The implementation of DTC
using space vector modulation that is used is described in detail.
DTC using space vector modulation is implemented on a custom-built embedded
controller based on a TMS320VC33 DSP and a XC4020XLA FPGA. The
implementation of the control algorithms and a number of supporting software
components are also described.
The implemented torque controller is tested against a 15hp, 400Hz, 200V induction
motor. Results are presented that show the performance of the torque controller and the
three-level space vector modulator. The three-level space vector modulator is shown to
produce less current distortion at low modulation indices. The torque produced by the
controller during steady-state operation differs from the reference torque, but this error is
relatively constant over the range of speeds that are tested. The estimated response to
step-changes in the torque and flux references are shown to be almost instantaneous.
9
Ustuntepe, Bulent. "A Novel Two-parameter Modulation And Neutral Point Potential Control Method For The Three-level Neutral Point Clamped Inverter." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606928/index.pdf.
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In this thesis, the neutral point potential drift/fluctuation of the three-level neutral
point clamped inverter is analyzed and a novel control algorithm, the two-parameter
PWM method is proposed to confine the neutral point potential variation to a very
small range. The two-parameter PWM method provides superior neutral point
potential control performance even with small DC bus capacitors. The method is
based on PWM pulse pattern modification and requires no additional hardware.
Detailed analytical models of the neutral point current and potential as a function of
the modulation parameters are established and the neutral point potential behavior is
thoroughly investigated. Based on the study, the deficiency of the known methods is
illustrated and the two-parameter PWM method is developed and its superior
performance demonstrated. The performance of the two-parameter PWM method is
verified by means of computer simulations utilizing both the per-PWM-cycle
average model and the detailed model of the inverter. The results are supported by
laboratory experiments involving both an R-L load and an induction motor drive.
10
Phan, The Minh [Verfasser]. "Protection of the switches in a three-level inverter by using modified switching schemes for the redistribution of losses / The Minh Phan." Siegen : Universitätsbibliothek der Universität Siegen, 2016. http://d-nb.info/1123283729/34.
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Elamalayil, Soman Deepak. "Multilevel Power Converters with Smart Control for Wave Energy Conversion." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332730.
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The main focus of this thesis is on the power electronic converter system challenges associated with the grid integration of variable-renewable-energy (VRE) sources like wave, marine current, tidal, wind, solar etc. Wave energy conversion with grid integration is used as the key reference, considering its high energy potential to support the future clean energy requirements and due the availability of a test facility at Uppsala University. The emphasis is on the DC-link power conditioning and grid coupling of direct driven wave energy converters (DDWECs). The DDWEC reflects the random nature of its input energy to its output voltage wave shape. Thereby, it demands for intelligent power conversion techniques to facilitate the grid connection. One option is to improve and adapt an already existing, simple and reliable multilevel power converter technology, using smart control strategies. The proposed WECs to grid interconnection system consists of uncontrolled three-phase rectifiers, three-level boost converter(TLBC) or three-level buck-boost converter (TLBBC) and a three-level neutral point clamped (TLNPC) inverter. A new method for pulse delay control for the active balancing of DC-link capacitor voltages by using TLBC/TLBBC is presented. Duty-ratio and pulse delay control methods are combined for obtaining better voltage regulation at the DC-link and for achieving higher controllability range. The classic voltage balancing problem of the NPC inverter input, is solved efficiently using the above technique. A synchronous current compensator is used for the NPC inverter based grid coupling. Various results from both simulation and hardware testing show that the required power conditioning and power flow control can be obtained from the proposed multilevel multistage converter system. The entire control strategies are implemented in Xilinx Virtex 5 FPGA, inside National Instruments’ CompactRIO system using LabVIEW. A contour based dead-time harmonic analysis method for TLNPC and the possibilities of having various interconnection strategies of WEC-rectifier units to complement the power converter efforts for stabilizing the DC-link, are also presented. An advanced future AC2AC direct power converter system based on Modular multilevel converter (MMC) structure developed at Siemens AG is presented briefly to demonstrate the future trends in this area.
12
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.
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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.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.
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.
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.
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.
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.
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.
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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Yildirim, Dogan. "Field Oriented Control Of A Permanent Magnet Synchronous Motor Using Space Vector Modulated Direct Ac-ac Matrix Converter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614302/index.pdf.
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The study designs and constructs a three-phase to three-phase direct AC&ndashAC matrix converter based surface mounted permanent magnet synchronous motor (PMSM) drive system. First, the matrix converter topologies are analyzed and the state-space equations describing the system have been derived in terms of the input and output variables. After that, matrix converter commutation and modulation methods are investigated. A four-step commutation technique based on output current direction provides safe commutation between the matrix converter switches. Then, the matrix converter is simulated for both the open-loop and the closed-loop control. For the closed-loop control, a current regulator (PI controller) controls the output currents and their phase angles. Advanced pulse width modulation and control techniques, such as space vector pulse width modulation and field oriented control, have been used for the closed-loop control of the system. Next, a model of diode-rectified two-level voltage source inverter is developed for simulations. A comparative study of indirect space vector modulated direct matrix converter and space vector modulated diode-rectified two-level voltage source inverter is given in terms of input/output waveforms to verify that the matrix converter fulfills the two-level voltage source inverter operation. Following the verification of matrix converter operation comparing with the diode-rectified two-level voltage source inverter, the simulation model of permanent magnet motor drive system is implemented. Also, a direct matrix converter prototype is constructed for experimental verifications of the results. As a first step in experimental works, filter types are investigated and a three-phase input filter is constructed to reduce the harmonic pollution. Then, direct matrix converter power circuitry and gate-driver circuitry are designed and constructed. To control the matrix switches, the control algorithm is implemented using a DSP and a FPGA. This digital control system measures the output currents and the input voltages with the aid of sensors and controls the matrix converter switches to produce the required PWM pattern to synthesize the reference input current and output voltage vectors, as well. Finally, the simulation results are tested and supported by laboratory experiments involving both an R-L load and a permanent magnet synchronous motor load. During the tests, the line-to-line supply voltage is set to 26 V peak value and a 400 V/3.5 kW surface mounted permanent magnet motor is used.
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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 VillalvaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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
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
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
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Alepuz, Menéndez Salvador Simón. "Aportación al control del convertidor CC/CA de tres niveles." Doctoral thesis, Universitat Politècnica de Catalunya, 2004. http://hdl.handle.net/10803/6330.
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La presente tesis estudia, propone y realiza sus principales aportaciones en el campo del control para el convertidor CC/CA de tres niveles, sobre la topología denominada Neutral-Point-Clamped, aunque se puede extender a otras topologías y/o número de niveles. Se presenta una metodología de modelado que emplea funciones de conmutación de fase, el operador de promediado y la transformación D-Q, tal que los modelos obtenidos en el dominio D-Q contienen una información completa sobre la dinámica del sistema. La estrategia de conmutación se puede entender como una extensión de la estrategia PWM senoidal de dos a tres niveles. Esta estrategia es simple y no realiza el control de ninguna de las variables del sistema. En esta tesis, el controlador se encarga de regular todas las variables del sistema, incluido el equilibrio del bus de continua. Este es un enfoque diferente del convencional, donde el equilibrio del bus de continua se consigue mediante la elección adecuada de los estados redundantes del convertidor en la estrategia de conmutación, mientras que el resto de variables se regulan a través del controlador. Para la realización del controlador, se propone la técnica de control lineal multivariable LQR (Linear Quadratic Regulator), complementada con la técnica de control no lineal adaptativo denominada programación de ganancia (Gain Scheduling). Se presenta, además, una metodología de cálculo del controlador. Este control es versátil, abierto y adaptable. En cualquier caso, el controlador se puede adaptar a las necesidades concretas de cada aplicación. El cálculo del controlador se realiza mediante simulación con MatLab-Simulink. Los modelos matemáticos que emplean las funciones de conmutación del convertidor son aquellos que ofrecen un mejor compromiso entre velocidad de simulación y precisión. Para validar el control propuesto, se ha diseñado y construido un equipo experimental donde el controlador se ha mostrado aplicable, útil y eficaz en la regulación de las distintas cargas y aplicaciones experimentadas, incluso con carga no lineal, bajo diferentes condiciones de trabajo y variables a controlar, tanto en régimen permanente como en procesos transitorios. La rapidez y calidad de la respuesta transitoria es comparable a la de otros sistemas de control publicados. Es especialmente interesante el excelente control conseguido del equilibrio del bus de continua. Además, la robustez del control permite cancelar el error estacionario aunque diferentes parámetros del sistema presenten desviaciones significativas respecto los valores esperados. El uso de la programación de ganancia junto con la técnica LQR se ha mostrado muy efectivo, puesto que permite realizar diferentes tipos de control. Se ha comprobado la congruencia entre simulaciones y resultados experimentales obtenidos, lo que valida los modelos de simulación empleados y el proceso de diseño del controlador mediante simulación.This dissertation study, propose and carry out the main contributions in the field of three-level inverter control, using the topology Neutral-Point-Clamped, although results can be extended to other topologies and/or number of levels. A procedure for modelling is presented, based on line-switching functions, moving average operator and D-Q transformation. Then, the obtained models in D-Q frame contain complete information about system dynamics. Switching strategy is simple and can be considered as an extension of two-level sinusoidal PWM to three level. The system variables are not controlled by the switching strategy. In this work, all the system variables are controlled by the regulator, including DC-link balance. This control approach is different than the conventional one, where DC-link balance is achieved by means of a proper selection of redundant states in the switching strategy, and the other variables are controlled by the regulator. The regulator is based on the multivariable linear control technique LQR (Linear Quadratic Regulator), in combination with the non-linear adaptive control technique Gain Scheduling. Moreover, a methodology for the calculation of the controller is presented. This controller is versatile, open and adaptable. However, the controller can be built depending on the concrete specifications of each application. The controller is calculated by means of simulation using MatLab-Simulink. The mathematical models based on the switching functions of the converter give the best trade-off between simulation speed and precision. In order to validate the proposed controller, an experimental prototype has been designed and implemented. Experimental results show that the controller is useful and effective for the regulation of different loads and applications, even with non-linear loads, different operation points and variables to control, in steady-state and transitory operation. Dynamic response speed and quality are similar to other control systems in the literature. The DC-link balance control achieved is specially interesting. Furthermore, steady-state error is cancelled due to the robustness of the controller, even though significant deviation of different system parameters are present. The use of Gain-Scheduling in combination with LQR is effective, allowing the calculation of regulators with different control strategies. Good agreement between simulations and experimental results has been found. This result validates simulation models and the design method for the controller, based on simulations.
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Alepuz, Menéndez Salvador Simón. "Aportació al control del convertidor CC/CA de tres nivells." Doctoral thesis, Universitat Politècnica de Catalunya, 2004. http://hdl.handle.net/10803/6330.
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La presente tesis estudia, propone y realiza sus principales aportaciones en el campo del control para el convertidor CC/CA de tres niveles, sobre la topología denominada Neutral-Point-Clamped, aunque se puede extender a otras topologías y/o número de niveles. Se presenta una metodología de modelado que emplea funciones de conmutación de fase, el operador de promediado y la transformación D-Q, tal que los modelos obtenidos en el dominio D-Q contienen una información completa sobre la dinámica del sistema. La estrategia de conmutación se puede entender como una extensión de la estrategia PWM senoidal de dos a tres niveles. Esta estrategia es simple y no realiza el control de ninguna de las variables del sistema. En esta tesis, el controlador se encarga de regular todas las variables del sistema, incluido el equilibrio del bus de continua. Este es un enfoque diferente del convencional, donde el equilibrio del bus de continua se consigue mediante la elección adecuada de los estados redundantes del convertidor en la estrategia de conmutación, mientras que el resto de variables se regulan a través del controlador. Para la realización del controlador, se propone la técnica de control lineal multivariable LQR (Linear Quadratic Regulator), complementada con la técnica de control no lineal adaptativo denominada programación de ganancia (Gain Scheduling). Se presenta, además, una metodología de cálculo del controlador. Este control es versátil, abierto y adaptable. En cualquier caso, el controlador se puede adaptar a las necesidades concretas de cada aplicación. El cálculo del controlador se realiza mediante simulación con MatLab-Simulink. Los modelos matemáticos que emplean las funciones de conmutación del convertidor son aquellos que ofrecen un mejor compromiso entre velocidad de simulación y precisión. Para validar el control propuesto, se ha diseñado y construido un equipo experimental donde el controlador se ha mostrado aplicable, útil y eficaz en la regulación de las distintas cargas y aplicaciones experimentadas, incluso con carga no lineal, bajo diferentes condiciones de trabajo y variables a controlar, tanto en régimen permanente como en procesos transitorios. La rapidez y calidad de la respuesta transitoria es comparable a la de otros sistemas de control publicados. Es especialmente interesante el excelente control conseguido del equilibrio del bus de continua. Además, la robustez del control permite cancelar el error estacionario aunque diferentes parámetros del sistema presenten desviaciones significativas respecto los valores esperados. El uso de la programación de ganancia junto con la técnica LQR se ha mostrado muy efectivo, puesto que permite realizar diferentes tipos de control. Se ha comprobado la congruencia entre simulaciones y resultados experimentales obtenidos, lo que valida los modelos de simulación empleados y el proceso de diseño del controlador mediante simulación.This dissertation study, propose and carry out the main contributions in the field of three-level inverter control, using the topology Neutral-Point-Clamped, although results can be extended to other topologies and/or number of levels. A procedure for modelling is presented, based on line-switching functions, moving average operator and D-Q transformation. Then, the obtained models in D-Q frame contain complete information about system dynamics. Switching strategy is simple and can be considered as an extension of two-level sinusoidal PWM to three level. The system variables are not controlled by the switching strategy. In this work, all the system variables are controlled by the regulator, including DC-link balance. This control approach is different than the conventional one, where DC-link balance is achieved by means of a proper selection of redundant states in the switching strategy, and the other variables are controlled by the regulator. The regulator is based on the multivariable linear control technique LQR (Linear Quadratic Regulator), in combination with the non-linear adaptive control technique Gain Scheduling. Moreover, a methodology for the calculation of the controller is presented. This controller is versatile, open and adaptable. However, the controller can be built depending on the concrete specifications of each application. The controller is calculated by means of simulation using MatLab-Simulink. The mathematical models based on the switching functions of the converter give the best trade-off between simulation speed and precision. In order to validate the proposed controller, an experimental prototype has been designed and implemented. Experimental results show that the controller is useful and effective for the regulation of different loads and applications, even with non-linear loads, different operation points and variables to control, in steady-state and transitory operation. Dynamic response speed and quality are similar to other control systems in the literature. The DC-link balance control achieved is specially interesting. Furthermore, steady-state error is cancelled due to the robustness of the controller, even though significant deviation of different system parameters are present. The use of Gain-Scheduling in combination with LQR is effective, allowing the calculation of regulators with different control strategies. Good agreement between simulations and experimental results has been found. This result validates simulation models and the design method for the controller, based on simulations.
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Yao, Jilong. "Assessment of the topology and control of three-level inverters for low-voltage distributed generation." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433506.
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Riachy, Léa. "Contribution à la commande d'un onduleur multiniveaux, destinée aux énergies renouvelables, en vue de réduire le déséquilibre dans les réseaux électriques." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR076/document.
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Le travail de cette thèse apporte une contribution aux méthodes de réglage de la tension dans les réseaux électriques. Il s’agit de fournir au réseau la puissance active et surtout la puissance réactive nécessaire pour réguler la tension et aboutir à un système équilibré vue du côté source. Ces puissances sont extraites d’une source d’energie renouvelable : une attention particulière a été portée à l’énergie éolienne raccordée au réseau à travers la Machine Asynchrone à Double Alimentation (MADA) pilotée par des convertisseurs statiques. Le système de contrôle le plus répandu des éoliennes est basé principalement sur la technique d’extraction du maximum de puissance. Cependant, cette technique limite la mise en oeuvre deservices auxiliaires, telle que la participation des éoliennes au réglage de la tension dans le réseau électrique. Pour cela, une nouvelle méthode d’extraction du coefficient de puissance optimal, permettant d’améliorer la participation de la MADA à la régulation de la tension dans le réseau (compensation de la puissance réactive et du déséquilibre), a été développée. Le convertisseur multiniveaux à structure NPC (Neutral Point Clamped) raccordant l’énergie renouvelable au réseau a été étudié. La commande prédictive assurant simulatnément l’amélioration du facteur de puissance, l’équilibrage du réseau électrique et du bus continu du convertisseur NPC a été proposée. Ensuite, l’application de cette commande prédictive a été elargie en lui attribuant plusieurs objectifs : amélioration du facteur de puissance avec équilibrage du réseau, équilibrage du bus continu, minimisation des pertes par commutation et réduction de la tension de mode commun. La minimisation des pertes a été obtenue en proposant une nouvelle stratégie qui consiste à exploiter les datasheets constructeurs donnant l’évolution de l’énergie dissipée durant la commutation en fonction du courant. Ces courbes expérimentales ont été transformées en modèlesmathématiques implémentés dans la commande prédictive. Les résultats de simulation et expérimentaux sont présentés pour évaluer les performances de la méthode proposéeThe work in this research thesis presents a contribution to voltage regulation in electrical networks. By considering adequate active and reactive powers injection into the grid, voltage control and load balancing are provided. These powers are generated from a grid connected renewable energy conversion system : a special attention was paid to the Wind Energy ConversionSystem (WECS) based on Doubly-Fed Induction Generator (DFIG).The typical control strategy for WECS is the maximum power coefficient tracking method. However, this method limits desirable ancillary power services, such as the participation of wind turbines in voltage regulation in the power grid. Therefore, a new method that derives the optimal power coefficient enhancing the participation of WTS in voltage regulation in the network (reactive and unbalanced power compensation), has been developed. The multilevel NPC (Neutral Point Clamped) converter, used for grid interface connection of renewable energy sources systems, has been studied. A predictive control method for the three-level NPC converter, capable of simultaneously compensating the problems of : DC link capacitors voltage balancing, load balancing and power factor correction in the power system, has been proposed. Then, the application of this predictive control was extended to simultaneously achieve multiple objectives: load balancing with power factor correction in the network, DC link capacitors voltage balancing, switching losses minimization and common mode voltage reduction. The switching losses minimization was obtained by proposing a new strategy which consists on exploiting the manufacturer datasheets that gives the evolution of the switching loss energy in function of the circulating current. The experimental curves of the datasheet are expressed in a mathematical model implemented in the predictive control. Simulation and experimental results are presented to evaluate the performance of the proposed method
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Gaptia, Maï Moussa Lawan. "Gestion optimale d'énergie électrique à partir des sources d'énergies renouvelables dédiées aux sites isolés Power control for decentralized energy production system based on the renewable energies — using battery to compensate the wind/load/PV power fluctuations Three level Neutral-Point-Clamped Inverter Control Strategy using SVPWM for Multi-Source System Applications Wind turbine and Batteries with Variable Speed Diesel Generator for Micro-grid Applications." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMLH28.
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Les travaux de thèse s’inscrivent dans les problématiques des travaux de recherche de l’équipe thématique : Maitrise des Energies Renouvelables et systèmes de Stockage (MERS) du laboratoire GREAH-EA3220. Ils englobent le dimensionnement des éléments constitutifs du système et la gestion optimale de l’énergie électrique pour un système hybride (Diesel à vitesse variable, Eolien, PV et Batteries) dédié aux sites isolés. Les sources de production d'énergie alimentent des charges par le biais de convertisseurs multi-niveaux d’électronique de puissance. Le groupe électrogène comportant un moteur diesel à vitesse variable est considéré comme la principale source d’énergie utilisée pour contrôler la tension continue du point de couplage. Ce type de groupe électrogène est choisi pour optimiser la consommation du carburant. Il est sollicité pour délivrer une puissance électrique compatible avec le régime du moteur qui supporte mal les variations fréquentes et rapides. Les sources d’énergie renouvelables dont on cherche à augmenter la part d’énergie pour satisfaire la demande sont pilotées de manière à extraire instantanément le maximum de puissances disponible par les ressources (ensoleillement, vent). Celles-ci imposent ainsi leurs dynamiques et leurs intermittences au point de couplage. Le pack des batteries sert à compenser les fluctuations rapides de l’énergie provenant des sources d’énergie renouvelables par rapport à une évolution plus lente prise en charge par le groupe électrogène. La gestion des interactions au sein du système électrique hybride résultant est assurée au moyen de convertisseurs statiques multi-niveaux (AC / DC, DC / DC et DC / AC). Une approche de gestion d’énergie électrique fondée sur la répartition fréquentielle des perturbations induites au point de couplage par les sources renouvelables. Une plateforme expérimentale à échelle réduite (1/22) a été développée pour valider expérimentalement les approches théoriques et les simulations. Les résultats de simulations obtenus dans l’environnement logiciel Matlab/Simulink/SimPowerSystems et ceux issus du dispositif expérimental réalisé et piloté par dSPACE-1104 prouvent l’adéquation des méthodes de contrôle proposéesThe thesis works are part of the research work of the thematic team: Mastery of Renewable Energies and Storage Systems (MERS) of the GREAH-EA3220 laboratory. They include the dimensioning of the constituent elements of the system and the optimal management of electrical energy for a hybrid system (Variable speed Diesel, Wind, PV and Batteries) dedicated to isolated sites. Power sources supply loads through multi-level converters of power electronics. The generator set with a variable speed diesel engine is considered to be the main source of energy used to control the DC voltage at the coupling point. This type of generator is chosen to optimize fuel consumption. It is used to deliver an electrical power compatible with the engine speed which does not tolerate frequent and rapid variations. Renewable energy sources whose share of energy is sought to meet demand are managed so as to instantly extract the maximum power available from resources (sunshine, wind). These thus impose their dynamics and their intermittences at the coupling point. The battery pack is used to compensate for rapid fluctuations in energy from renewable energy sources compared to a slower evolution supported by the generator. Interactions within the resulting hybrid electrical system are managed by means of multi-level static converters (AC / DC, DC / DC and DC / AC). An electrical energy management approach based on the frequency distribution of disturbances induced at the coupling point by renewable sources. An experimental platform on a reduced scale (1/22) has been developed to experimentally validate theoretical approaches and simulations. The results of simulations obtained in the Matlab / Simulink / SimPowerSystems software environment and those from the experimental device produced and piloted by dSPACE-1104 prove the adequacy of the proposed control methods
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Dai, Ning Yi. "A generalized 3D pulse width modulator for multi-level voltage source inverters in three-phase four-wire power systems." Thesis, University of Macau, 2007. http://umaclib3.umac.mo/record=b2151603.
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Cai, Xinbo [Verfasser]. "Optimum Control of Electrical Drives and Power Converters : Computational Efficient Optimum Control for Three-Level-Inverters with DC-link Capacitance Balancing / Xinbo Cai." Düren : Shaker, 2021. http://d-nb.info/1233548417/34.
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Yang, An-Li, and 楊安立. "Design and Implementation of Three phase Three level Inverter." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/79hauh.
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碩士國立臺灣科技大學
電子工程系
106
This thesis proposes the design and implementation of a digitally-controlled three phase three level inverter. The proposed three level circuit which is using T-type topology. The benefits of this topology are using fewer components, reducing the devices stress and the lower output voltage THD. A digital signal processor (DSP) chip is Texas Instruments TMS320F28335. It’s a high performance digital control chip and also has floating-point unit (FPU). Therefore, it’s suitable for three phase controlled application. The proposed modulation strategy is carrier-based pulsewidth modulation. This technique can be implemented with a very simple algorithm and, hence, can be processed very quickly. In addition, it can generate the maximum modulation index up to 1.154 that is attainable under linear modulation, such as space vector modulation. Finally a 6 kW three phase T-type inverter is implemented.
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Hsin-HungChen and 陳信宏. "A Novel Three-Phase Five-Level Inverter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87041337151570512045.
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碩士國立成功大學
電機工程學系碩博士班
101
In this thesis, a novel three-phase five-level inverter is proposed. The proposed topology constructed of twelve power switches and twelve diodes to achieve a three-phase five-level AC Y-connected output. The output line-to-line voltage is five levels and total harmonic distortion is lower. Compared to the traditional three-phase inverters, the proposed three-phase five-level inverter can achieve the five output voltage levels with fewer components. In this thesis, the details of the mode analyses and control methods are discussed. An experimental prototype with input voltage 500 V, output power 6 kW, THD 3.62%, and efficiency 98.40% is implemented to verify the theory and feasibility of the proposed topology.
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Du, Chang-Long, and 杜昌隆. "Design of a FPGA Based Three-Level Inverter." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/17695200979113309504.
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碩士國立交通大學
電機與控制工程系
87
The thesis presents a three-level inverter research based on the space vector pulse width modulation( SVPWM ) strategy .The SVPWM theorem was chosen owing to higher voltage utility，lower switching loss and lower harmonic distortion comparing to SPWM( Sinusoidal Pulse Width Modulation ) theorem. Three-level inverter is suitable for large capacity and high voltage AC drives, since the blocking voltage of each switching devices is clamped to half of Dc-link voltage and harmonic component of the output voltage is less then those of the conventional two-level inverter at the same switching frequency. We have made the three-level inverter modal based on PC and FPGA successfully. The PC software generates SVPWM duty and calculates the position of space voltage vector. FPGA is responsible for SVPWM waveform generation and delay-time compensation. The switching frequency and the delay-time compensation in this system are programmable In controlling three-level inverter system, four switching patterns have been studied in order to minimize the harmonic components of the output voltage. The problem of neutral-point DC voltage unbalance is considered carefully in this system. The influence of switching states on neural point DC voltage is discussed based on a simplified motor modal. The compensation method of neural point DC voltage proposed in this paper help to control the stability of neutral voltage. Simulation and experimental results are given to verify the realization of SVPWM three-level inverter.
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Lin, Shu-Yong, and 林書永. "Development of Digital Signal Processor Based Parallel Three–Phase Three-Level Power Inverter Systems." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/23735045695037221772.
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碩士國立臺灣科技大學
電機工程系
96
This thesis presents the development of parallel three-phase inverter systems. In the three-phase inverter system, the three-level switching is designed to reduce the output voltage harmonics. The first power inverter is operated at voltage-controlled mode which uses voltage closed-loop control to provide stable and low-harmonic ac voltage source to load, while the second parallel power inverter is operated under current-controlled mode which uses current closed-loop control to supply the power in accordance with the build-in power-distribution list, and thereby achieves paralleling control and load-sharing. In this thesis, the digitized mathematical models are built. The strategies of voltage and current closed-loop controls using the coordinate transformation are inferred. Then, a high-performance, low-cost digital signal processor (DSP, TMS320LF2812) and complex programmable logic device (CPLD, XC9536) is used to implement the system for reducing the circuit components and cost. Experimental result for single power inverter yields the full-load power of 750W with voltage harmonic distortion of . Whereas, with 1kW parallel controlled system, each power inverter loads half of the output load power by using the strategy of balanced current sharing. In order to increase the reliability, master-slave control technique is used.
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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.
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碩士國立高雄應用科技大學
電機工程系博碩士班
104
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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Yu-tin and 林育廷. "The manufacture and research of the three level inverter system on chip." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/45377799922055486347.
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碩士國立臺灣科技大學
機械工程系
91
System On Chip technique has been used expansively in motor control, and makes the motor drive more compact, more reliable and more powerful. To complete a motor control chip, not only the high performance digital controller, but also the analog input interface and the pulse width modulator are needed to form the basic motor control chip. The traditional motor control chip is made of high-speed microprocessor core, and motor control peripheral, and the user write program to control the behavior of the microprocessor. The software develop process is very tedious and often be a trouble when the control software is very enormous. The software calling subroutine process often spends a lot of time to save the program execute result temporarily, and waste CPU resource. If we use the option to optimize the software for speed, the software may cause more serious problem. Facing this problem, somebody has proposed the hardware implement to instead the software implement, and try to use enormous programmable elements to implement the specific motor control integrated circuit, and there’s no need to write program to control the motor, just need to configure and command the chip to control motor. The programmable element technique has progressed very well in recent years. More capacity, and faster programmable elements appear in every year, and function progresses from the programmable digital elements to the programmable analog-digital mixed elements, these progress makes the system on chip more convenient. A DSP micro controller and FPGA (Field Programmable Gate Array) mixed development tools will be used to implement the 3 phase 3 level inverter system on chip in this paper. We will use these tools to move the DSP controller into the FPGA gradually, and implement the 3 phases 3 level PWM controller in the FPGA.
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Li, Bing-Feng, and 李柄鋒. "Tolerant Control of Open-Circuit Fault for Three-Level T-type Inverter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/09610942677366275414.
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碩士國立中山大學
電機工程學系研究所
104
As there are more applications of T-type inverter, the concern of the inverter reliability has been increasing. This thesis investigates the operation modes of three-level T-type inverter circuit, proposed a new method to detect fault phase .The proposed method can locate fault switch by detecting the average value of phase current and the situation of unbalance voltage of capacitors. Carrier-based pulse width modulation is applying to achieve the tolerance control, and making the modulation scheme more easier to implement. A neutral-point voltage balance control for three-level T-type inverter is also applied. Finally, the availability and performance of the proposed of open-circuit fault tolerant control are verified with the laboratory prototype.
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Yang, Chih-Hung, and 楊芷妅. "Design of Integrated Circuit of Pulse-Width Modulation Control for Three-Level Inverter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/7t36hr.
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碩士國立臺北科技大學
電機工程系研究所
97
The purpose of this thesis is to design and implement the control technique for the three-level inverter of induction motor by Application Specific Integrated-Circuit in TSMC .18μm technology. The three-level inverter employed is diode-clamped and we have conquered the problem of the voltage of the neutral point in balance. In this thesis a pulse-width modulation technique is presented which provides voltage balance between two DC-link capacitors and reduces the total harmonic distortion of output waveforms. The presented method requires voltage sensor only and can be realized based upon space vector modulation. The simulation results are derived from Matlab®/Simulink®, and the experimental results are derived from an induction motor drive controlled by FPGA. The 12 signals of the inverter are controlled by a mechanism of Space Vector PWM, and feedback the voltage between the 2 capacitors to compensate the bias of the voltage of the neutral point. It will be shown that the simulation results and experimental results agree with other very well and confirming the performance of the presented control technique for three-level inverter. Finally we utilize EDA tools to design a cell-based integrated circuit system fulfilling the goals.
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Huang, Chi-Lin, and 黃麒霖. "Design and Implementation of a High Power Three-Level Neutral-Point-Clamped Inverter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/qsa7nx.
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碩士國立臺灣科技大學
電機工程系
104
This thesis presents the development of a 50-kilowatt three-level diode-clamp inverter. The implementation of this high power inverter includes a main power stage, modified gate-trig circuits, a DSP-based digital controller. Moreover, the thermal analysis of a forced-air-cooling sink is investigated for full-power operation. Multi-level inverters are superior to traditional two-level structures, such as less losses, lower harmonics and voltage stress, resulting in better performance. In this thesis, the inverter is designed to drive a high-power high-torque serve motor with 50-kW rated power by current control method. Thus, two current control strategies, linear current control and infinite state model predict control, are employed to achieve the control goal, in which 400Hz bandwidth and 100% over load capability are required. The two control strategies are implemented by two DSP controllers, TMS320F28069 and TMS320F28335, respectively. For dealing with the high power requirement, the layout of the main power stage is designed carefully. The inductance-free bus is used to reduce the voltage spike posed on the switches, and the modified gate-trig circuits are used to drive the high-current-rating IGBT devices properly. All these efforts prove the stability of the inverter which can operate at full power for more than two hour, even it is only a prototype. Taking the advantages of the 3-level structure, the inverter provides very high efficiency over the full operation range with the highest 98.6%. Finally, both simulation and experiment results demonstrate that the inverter not only meets the design requirement but also operates with well performance.
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Wu, Xuan-Ru, and 吳宣儒. "Application of abc Reference Frame SVPWM Algorithm to Three-Phase Three-Level T-Type Voltage Source Inverter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/46n79e.
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碩士國立交通大學
電控工程研究所
107
In this thesis the abc reference frame continuous SVPWM algorithm is adapted for a three-phase three-level T-Type voltage source inverter. The proposed algorithm has low computational complexity, hence no memory is required for recording the multilevel switching states and their corresponding duty ratios, making it of facile implementation in microcontrollers. The proposed algorithm consider both algorithm verification and closed-loop operation. The algorithm verification, uses one reference voltage vector in the alpha-beta plane to compute four multilevel switching vectors and their corresponding duty ratios. Then the multilevel switching vectors are mapped onto the three-phase three-level T-Type voltage source inverter to get twelve switch gate driver signals. In closed–loop operation, the output phase currents follow the current commands when the inverter operates in the linear region. The capacitor balance control is also added to balance both DC-link capacitors average voltage. The proposed algorithm will be verified through the simulation software PSIM and implemented using a FPGA to prove the feasibility of the proposed algorithm.
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Hsieh, Tsung-Yu, and 謝宗佑. "A Circuit-Level Decoupling Principle Based Discontinuous Pulse Width Modulation Strategy for Three Level Neutral-Point-Clamped Inverter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/zn2n5h.
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碩士國立中山大學
電機工程學系研究所
103
Multilevel inverter technology has emerged recently as a very important alternative in the area of medium-voltage (2.3, 3.3, 4.16, and 6.9 kv) energy control. The three level neutral-point-clamped (NPC) inverter is the most extensively applied multilevel inverter topology in this area. Based on the circuit-level decoupling principle, the implementation of modulation scheme can be significantly simplified in every defined operating section through deriving the zero-sequence voltage with assuming balanced neutral-point voltage. This thesis presents a carrier-based discontinuous pulse width modulation (DPWM) strategy with zero-sequence voltage injection and neutral-point voltage balancing control for the three level NPC inverter. The proposed DPWM strategy not only takes advantage of low voltage harmonic distortion, but also reduces the switching loss of the inverter. Finally, the viability and performance of the proposed DPWM strategy are verified in the laboratory prototype.
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Gopalakrishnan, K. S. "Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter." Thesis, 2013. http://etd.iisc.ernet.in/handle/2005/2628.
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Three-level diode-clamped inverter is being widely used these days. Extensive research has been carried out on pulse width modulation (PWM) strategies for a three-level inverter. The most widely used PWM strategies are sine-triangle pulse width modulation (SPWM) and centered space vector pulse width modulation (CSVPWM). The influence of these PWM strategies on the DC-link capacitor current and voltage ripple is studied in this thesis.
The sizing of the DC capacitor depends on value of the maximum RMS current flowing through it. In this work, an analytical expression for capacitor RMS current is derived as a function of operating conditions like modulation index, power factor angle of the load and peak load current. The worst case current stress on the capacitor is evaluated using the analytical expression. The capacitor RMS current is found to be the same in SPWM and CSVPWM schemes. The analytical expression is validated through simulations and experiments on a 3kVA MOSFET based three-level inverter.
Harmonic analysis of the capacitor current is helpful in better evaluation of capacitor power loss. Therefore, harmonic analysis of the capacitor current is carried out, using the techniques of geometric wall model and double Fourier integral for SPWM and CSVPWM schemes. The theoretical predictions are validated through experiments.
The capacitor RMS current is divided into low-frequency RMS current (where low frequency component is defined as a component whose frequency is less than half the switching frequency) and high-frequency RMS current. The capacitor voltage ripple is estimated analytically for SPWM and CSVPWM schemes, using the low-frequency and high-frequency capacitor RMS current. The voltage ripples due to SPWM and CSVPWM schemes are compared. It is found that the voltage ripple with SPWM is higher than that with CSVPWM. A simplified method to estimate the capacitor power loss, without the requirement of FFT analysis of capacitor current, is proposed. The results from this simplified method agree reasonably well with the results from the detailed method.
A space vector based modulation scheme is proposed, which reduces the capacitor RMS current at high power factor angles. However, the proposed method leads to higher total harmonic distortion (THD) than CSVPWM. Simulation and experimental results, comparing CSVPWM and the proposed PWM, are presented.
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SHEN, XWEI-TING, and 沈威廷. "Single-phase Three-wire Multi-level Inverter Developed by Wide Band-gap Power Devices." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/2awgda.
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碩士國立聯合大學
電機工程學系碩士班
105
This thesis develops a multi-level inverter using GaN power switch for the single-phase three-wire battery energy storage system (BESS). The GaN device is adopted to reduce the switching loss and conduction loss. The conventional inverter using IGBT and MOSFET devices usually sets the switching frequency to be around 20kHz. Switching frequency of the proposed inverter is increased to be 100kHz to reduce the circuit volume significantly. Hard switching PWM inverter with high switching frequency will cause high voltage spike. This thesis utilizes the three-level neutral-point diode-clamped inverter to reduce the voltage stress of the switch to be half of the DC-link voltage. The split-capacitor forms as the diode-clamp voltage source and associates with the two-arm switch to provide the three-wire output. As a part of the residential BESS, the inverter can be operated in stand-alone mode and grid-connected mode. This thesis derives the inverter model and designs the respective current and voltage controllers of each operation mode. A 2kW fully digital control inverter is designed and implemented. The effectiveness of the inverter circuit and controllers are demonstrated with some simulation and experimental results. Keywords: multi-level inverter, stand-alone mode, grid-connected mode, GaN power device, fully digital control
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(11198991), Harshita Singh. "Passive Mitigation of Common-Mode Current in Three-Phase Two-Level Inverter-Based Systems." Thesis, 2021.
Find full textAbstract:
Power electronic converters are being used in a variety of applications, from electric vehicles to the utility grid. These converters are designed to offer high efficiency, which is achieved by switching semiconductor devices between on or off states at a high frequency. Associated with this switching is a common-mode voltage. The high-frequency components in this voltage excite the parasitic capacitances in the system, resulting in the flow of common-mode current. Since this current completes its path through an unintended path, it can interfere with the functioning of other devices or equipment. One way to reduce the CM current in a system is through the use of passive components. These include strategically placed capacitors and common-mode inductors to limit the impact of the common-mode quantities.
While the design of common-mode inductors has been set forth in the literature, the effect of magnetic hysteresis in the core has been inappropriately ignored. This phenomenon becomes increasingly important when the allowable common-mode current is significantly smaller than the differential-mode current, such as in high-power converters.
In this work, passive mitigation of common-mode current in three-phase two-level voltage-source-inverter based systems is considered. A mitigation strategy is proposed and described. The components used in this strategy, namely a common-mode inductor and a proposed common-mode shorting network, are introduced. This is followed by a discussion on the time domain hysteresis modeling that facilitates the magnetic design of a common-mode inductor. The issue of self-capacitance of a common-mode inductor is then addressed. Then, a rigorous multi-objective optimization-based design methodology for a common-mode inductor which addresses magnetic hysteresis at a fundamental level is set forth.
This is followed by a discussion of a new tool in common-mode current mitigation, a proposed common-mode shorting network. A design strategy for this component is also set forth. The dissertation concludes with two experimental system demonstrations of the proposed strategy and components on laboratory test systems.
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Liu, Fang-Ta, and 劉枋達. "Modulating Strategy of Three-Level T-type Inverter Considering SOC of Series Battery Bank." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/739sq8.
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碩士國立中山大學
電機工程學系研究所
106
The three-level T-type inverter has received much interest in energy storage systems due to its high efficiency. The present thesis proposes a novel modulation for three-level T type inverter fed by two distinct battery banks in series connection as energy storages system. The proposed three-level modulation is able to control charge/discharge current of each battery banks to get SOC balancing. In addition, unbalanced condition of capacitors voltage should be considered in three-level modulation since the battery banks might be in different SOCs. Hereby, the inverter will be able to produce balanced output voltage without low order harmonics even under different voltage. Experimental results are provided to verify the proposed method.
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Yu, Ming-Hung, and 游明弘. "Two-Stage Three-Level Smart Inverter with Grid Support Functions Application for Photovoltaic System." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5ap5vm.
Full textAbstract:
博士國立交通大學
電控工程研究所
107
This dissertation developed a two-stage, three-level, 10 kW advanced inverter with multiple smart functions. The architecture that enabled switching between the two-stage and single-stage modes also facilitated wider voltage input conditions and higher conversion efficiency. For integrating smart control strategies into the inverter, this study developed a control strategy that enabled the determination of grid status and automatic adjustment of the inverter to maintain a maximum power output or volt–var control, frequency–watt control, and low-voltage ride-through modes, thereby sustaining grid stability and grid power quality. Moreover, this dissertation presents a skip control method for improving the efficiency under light load condition. The proposed control method assesses the operating mode of a system according to the energy of input voltage. When the energy is higher than a reference level, the system operates in a continual mode; otherwise, the system operates in a discontinue mode to improve the light load efficiency. Finally, a two-stage, three-level, 10 kW advanced inverter demonstrating a peak efficiency of 98.01% was constructed to verify the feasibility of the proposed system.
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Wu, Ting-Lien, and 吳定濂. "A Dipolar-Switched Three-Level T-Type Inverter to Suppress Neutral-Point Voltage Ripple." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/d38w4j.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
107
In recent years, three-level T-type inverter has been widely applied in solar power generation systems because of its advantages of high efficiency and low switching harmonics. In order to improve the efficiency of solar cell array, two solar cell strings with independent maximum power point tracking are respectively used as the power sources of three-level T-type inverter. However, the input DC voltages of three-level T-type inverter will be unbalanced and distort the output current. In addition, the traditional modulation method will result in the triple-fundamental-frequency oscillation at the neutral point of three-level T-type inverter. It will affect the maximum power point tracking of solar cell strings. Therefore, a hybrid modulation strategy combining dipolar modulation and zero-sequence voltage modulation is proposed in this thesis. The proposed hybrid modulation strategy can effectively suppress the triple- fundamental-frequency oscillation at the neutral point of three-level T-type inverter, and individually control the voltage of two current sources by controlling the neutral point voltage and total DC voltage. Moreover, it can control the output current of three-level T-type inverter with low distortion. A laboratory prototype is built to verify the performance of the proposed hybrid modulation strategy.
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XU, FU-QIANG, and 許富強. "Smart Fault-Tolerant Control and Locating Faults in a Three-Level T-Type Inverter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8bzf4e.
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碩士國立勤益科技大學
電機工程系
107
This thesis proposes a smart fault-tolerant control system based on chaos theory and extension theory for locating faults and executing tolerant control in a three-level T-type inverter. First, the system constantly monitors the fault states of the 12 power transistor switches of the three-level T-type inverter; if a power transistor fails, the corresponding output phase voltage waveform is converted by a Lorenz chaotic synchronization system. Chaos eye coordinates are then extracted from a scatter diagram of chaotic dynamic states and considered as fault characteristics. The system then executes fault diagnosis based on extension theory. The fault characteristic value is used as the input signal for correlation analysis; thus, the faulty power transistor can be located and fault diagnosis can be achieved for the inverter. The faulttolerant control system can maintain the three-phase balanced output of the three-level T-type inverter, thereby improving the reliability of the motor drive system. The feasibility of the proposed smart fault-tolerant control system was assessed by conducting simulations and experiments in this thesis, and the results verified its feasibility.
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Chen, Yan-ning, and 陳彥寧. "Implementation of a Three-Phase Multi-Level Current Source Inverter Based on Selective Harmonic Elimination." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/87114734188344256900.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
98
This thesis proposes a multi-level current source inverter based on selective harmonic elimination technique. The required notch angles are solved from a set of non-linear simultaneous equations which is established by quarter-waveform symmetric assumption. Newton- Raphson method is used to solve the non-linear simultaneous equations through off-line calculation in a personal computer . Then, the solved notch angles are stored in a digital controller which employs a digital signal processor (TMS320F2812) and a complex programmable logic device (ispMACH 4256V). The multi-level current source inverter is consist of two stages: the dc current source stage and the inverter stage. The digital controller provides switching pattern for the switches in the two stages. In addition to the digital controller, a three-phase five-level current source inverter with output filter is built for test and measurement. Moreover, a simulation program is built to confirm the correction of the notch angles solved by off-line calculation through the harmonic analysis. Both the simulation and experimental results shows the validity of the proposed multi-level current source inverter.
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Wu, Sheng-Feng, and 巫昇峰. "Implementation of a three-level inverter based on zig-zag connected transformer using selective harmonic elimination." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/689pvf.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
95
This thesis applies the zig-zag transformer and the selective harmonics elimination PWM (SHEPWM) scheme to control a three-level inverter system. The PWM is designed to a quarter symmetry wave due the transformer’s characteristics. The wave applies the Newton-Raphson method to solve the exact curves, and then used the least squares solutions to obtain curve fitting equations. Due to the advantage property of curve fitting, the digital signal processor is able to control the fundamental value and change systematic frequency. Finally, experimental results confirm the system.
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Chen, Chi-Chang, and 陳基漳. "A New Three-Level Switching Topology Application to DC/DC Converter and DC/AC Inverter Design." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/33338291198912288117.
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碩士國立交通大學
電機資訊學院碩士在職專班
94
A new 3 level auxiliary circuit applicable to converters and inverters is proposed. The auxiliary circuit includes resonant capacitor, resonant inductor and bi-direction switch. This circuit can provide the natural clamp to eliminate oscillation from the leakage inductance of transformer and the soft switching function to both half-bridge converters and inverters. At the same time the switch can operate with zero-voltage switching while turning on. Furthermore, this circuit also provides the function to reduce half of the voltage stress of switch on the inverter application. The proposed circuit was identified with 12V/10A, 120W DC to DC converter and inverter application.
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Beig, Abdul Rahiman. "Application Of Three Level Voltage Source Inverters To Voltage Fed And Current Fed High Power Induction Motor Drives." Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1163.
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Tian, Yi. "Analysis, simulation and DSP based implementation of asymmetric three-level single-phase inverter in solar power system." 2007. http://etd.lib.fsu.edu/theses/available/etd-06222007-133201/.
Full textAbstract:
Thesis (M.S.)--Florida State University, 2007.Advisor: Jie J. Chang, Florida State University, FAMU-FSU College of Engineering, Dept. of Electrical and Computer Engineering. Title and description from dissertation home page (viewed July 18, 2008). Document formatted into pages; contains xi, 86 pages. Includes bibliographical references.
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Hu, Jyun-Wei, and 胡峻瑋. "Design and Implementation of Novel Predictive Current Controllers for a Three-Phase Two-Level Voltage Source Inverter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/81365713523009274314.
Full textAbstract:
碩士國立臺灣海洋大學
電機工程學系
104
This thesis proposes a novel model-free predictive current control for a three-phase two-level voltage source inverter. Unlike the predictive current control using seven voltage vectors, the proposed method uses 19 resultant voltage vectors, each of the vectors consisted of two voltage vectors. Since the numbers of available voltage vectors are increased from eight to nineteen, the predictive error can be effectively reduced. In addition, the proposed method does not require load parameters, back electromotive force, and system models. To compare to the model-based predictive current control, the proposed one belongs to a model-free approach because it is based on loading current detection, implying that the method is in sensitive to parameter variations. Finally, a TMS320F28335 digital signal controller, made by Texas Instruments Company, is used to validate the feasibility of the proposed method. From simulation and experimental results, there are better current-tracking performance in steady-state and transient responses than the existed predictive current control.
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Kuo, Chin-Chang, and 郭金璋. "FPGA-Based Implementation of Digital Controller for a Three-Phase Three-Level Active T-Type NPC Grid-Connected Inverter with LCL Filter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/xcv24t.
Full textAbstract:
碩士國立交通大學
電控工程研究所
105
The purpose of this thesis is to develop an FPGA-based controller in application to a three-phase three-level active NPC grid-connected inverter with LCL filter. The active T-type NPC (AT-NPC) combines the advantages of two-level inverter such as low conduction losses, with positive aspects of conventional NPC inverter such as low switching losses, low common-mode voltage and superior output waveform. For grid filter, LCL filter is adopted since it provides better harmonic attenuation capability with smaller inductance compared with L filter. However, LCL filter may lead to system unstable if no proper damping method is applied. In this thesis multi-loop control structure is utilized to mitigate the LCL resonance. It involves the use of outer loop and inner loop, with the outer loop ensuring steady-state reference tracking performance and the inner loop providing fast dynamic response for system disturbance and sudden reference changes. In this thesis predictive algorithm is applied for inner current loop regulation. Predictive control has the characteristic of dead-beat response therefore it can achieve fast dynamic response with minimum distortion. However, predictive control suffers from its high sensitivity to the accuracy of feedback current. Due to the reduction of inductance in LCL filter, large current ripple will occur on inverter-side. Conventional sampling strategy may not able to retrieve average current under such condition, therefore multi-sampling strategy is applied in this thesis. By multi-sampling technique the noise rejection capability is enhanced and SNR is improved. In addition, predictive control is also sensitive to parameter variations. If magnetic saturation effect occurs the inductance will decrease, which may lead to oscillation or even unstable in predictive control. In this thesis an on-line inductance estimator is developed to identify the inductance and maintain the dynamic response of the system. The designed controllers are implemented on a mixed-signal FPGA device. Experimental verifications are carried out on a 9-kW grid-connected inverter. The results show that the grid current are under well-controlled and even a sudden reference change occurs the designed controllers can still maintain system stable. The total inductance of LCL filter has a 65.38% reduction compared with that of L filter but still remain low harmonic distortion.
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Tsai, Yueh-Ting, and 蔡岳廷. "Leakage Current Reduction and Neutral Point Voltage Balancing Control for MVPWM-Controlled Three-Level T-Type PV Inverter." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nmej3g.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
107
The three level T-type inverter has been widely used in photovoltaic generation. In photovoltaic system, leakage current is ensued from the common mode voltage variation between the photovoltaic module and the ground. The leakage current results in photovoltaic cell performance induced deterioration (PID). This paper reduces leakage current by the basis of medium voltage vector pulse width modulation (MVPWM). Although MVPWM can achieve zero leakage current, however, the neutral-point voltage of the inverter is not able to be balanced due to medium-voltage vectors used only. Thus, by the discontinuous modulation, not only the generated P-type or N-type small-voltage vectors are added but also the minimize leakage current is considered to achieve the balance of the neutral-point voltage. Experiment results validate that the leakage current can be inhibited 55.28% by the proposed method.
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Figarado, Sheron. "Multilevel Inverter Topologies With Reduced Power Circuit Complexity For Medium Voltage High Power Induction Motor Drives By Cascading Conventional Two-Level And Three-Level Inveters." Thesis, 2009. http://hdl.handle.net/2005/1061.
Full textAbstract:
Multilevel inverters have advantages over two-level inverters such as reduced THD, ability to operate at low switching frequencies, reduced switching losses etc. Moreover, higher voltage levels can be handled with devices of lower voltage rating. The main disadvantage with the multilevel configurations compared to the two-level inverter configuration is the increase in the number of power devices required and the circuit complexity, which necessitates complex control schemes that add to the cost. Also, the reliability of the converters comes down as the number of devices increases. Reduction in complexity and modularity are desirable characteristics for the multilevel inverters.
Open-end winding Induction Motor (IM) drive configurations are shown to have advantages over the motor drive schemes with isolated neutral. The DC-link requirement in case of open-end winding structures comes down to half the voltage rating of the conventional NPC inverters. The DC- link requirement in case of open-end winding structures comes down to half compared to that of the conventional NPC inverters. The number of switching states is higher in the case of open-end winding configuration compared to multiplicity of switching states of conventional NPC inverters, which gives a control flexibility that can be used for optimizing the hardware requirements. Taking advantage of the flexibility given by open-end winding configuration, this thesis proposes schemes which have reduced power circuit complexity.
Non-sinusoidal voltage fed IM drives suffer from the problems related to the common mode voltage (CMV) generated by the inverters. This CMV causes bearing currents and shaft voltages which in turn cause increased conducted EMI, ground loop currents and premature bearing failure. A three-level scheme was proposed for an open-end winding Induction machine in the literature, which completely eliminate the CMV variation from the pole voltages as well as the phase voltages. This configuration uses 24 controlled switches and two isolated DC-sources. In this thesis, three-level inverter schemes with CMV elimination and reduced power device count for an open-end winding IM drive are proposed. The first scheme gets the reduction in switch count by sharing the top inverter of the three-level scheme and the second scheme achieves the same by sharing the bottom inverter. This way, the number of controlled switches comes down to 18 from 24.
Another problem with multilevel inverters is the large number of isolated DC-sources required to achieve the multilevel inversion. Reducing the number of isolated supplies and using capacitors to split the voltage levels poses the problem of capacitor voltage balancing. A four-level inverter with both CMV elimination and capacitor voltage balancing for an open-end winding IM drive is proposed in this thesis. The motor is fed by two four-level inverters from both the sides. A closed loop capacitor voltage balancing scheme is implemented and the redundancies in the switching states are used for achieving the capacitor voltage balancing and thereby reducing the total number of DC-link to two. The control scheme is independent of the load power factor and maintains the balance in the entire modulation range.
A five-level inverter scheme is proposed for an open-end winding IM drive in this thesis. It requires only two isolated DC-sources to achieve the five-level inversion. The motor is fed by one NPC three-level inverter from one side and a two-level inverter from the other. The inverters on either side share the DC-sources. Common mode voltage in the phases are made zero in an average sense using sine-triangle modulation in the proposed scheme so that the common mode currents through the phases are suppressed. The maximum fundamental voltage that can be obtained at the phase is limited to 0.5Vdc. DC-link requirement of the inverter scheme is half of that of conventional five-level inverter scheme because of the open-end winding structure. The two-level inverter, which should withstand half the DC-link voltage, is always in square wave operation and hence the switching losses are very less.
All the schemes are simulated extensively in MATLAB/Simulink and experimentally verified on laboratory prototypes under V/f control. TI Motor control DSP and Xilinx CPLD/FPGA are used for generation of the PWM signals for the schemes. The inverters are switched at around 1.25 kHz to keep the switching losses low. Due to laboratory constraints, the experimental verification is done on low power prototypes. Nonetheless, the generality of the schemes allow them to be used for medium voltage high power applications.
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Cherradi, Hassan. "Loss calculation in snubbers for three-level inverters." 1993. http://catalog.hathitrust.org/api/volumes/oclc/32538232.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 107-109).
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Chou, Yi-Kai, and 周逸凱. "Design and Implementation of Diode-Clamped Three-Level Inverters." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/8ppmt2.
Full textAbstract:
碩士國立臺北科技大學
機電整合研究所
94
The purpose of this thesis is to develop the control technique for three-level inverter. In this thesis a new pulse-width modulation technique is proposed which provides voltage balance between two DC-link capacitors while reducing the harmonic contents as compared to the existing method. The presented technique is to divide the reference voltage vector into six regions rather than four regions for conventional method. The presented method requires voltage sensor only and can be realized based upon space vector modulation. The presented technique is verified by both simulation and experimental results. The simulation results are derived from Matlab®/Simulink® software. And the experimental results are derived from an induction drive controlled by digital signal processor. It will be shown that the simulation results agree with experimental results very well and confirming the performance of the presented control technique for three-level inverter.