Dissertations / Theses: 'Three phase voltage source inverter'

1

Un, Emre. "Common Mode Voltage And Current Reduction In Voltage Source Inverter Driven Three Phase Ac Motors." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609062/index.pdf.

Full text

Abstract:

In this thesis various reduced common mode voltage (RCMV) pulse width modulation (PWM) techniques and active/passive common mode voltage (CMV) reduction methods for voltage source inverter driven three-phase AC motors are theoretically and practically investigated. A novel RCMV-PWM method, the near state PWM (NSPWM) method is proposed for operation at high modulation index. At low modulation index, a modified version of an existing RCMV-PWM method, AZSPWM1, termed as MAZSPWM, is proposed to mitigate the voltage reflection problem of the method. An optimum modulation algorithm combining NSPWM and MAZSPWM with seamless transition is proposed. The proposed RCMV-PWM methods significantly reduce CMV but they suppress common mode current (CMC) partially. Utilization of a common mode inductor together with RCMV-PWM methods is effective in suppressing the CMC. In the study, in addition to the CMV characteristics, various practical performance characteristics such as voltage linearity, inverter output current ripple, inverter DC-link current ripple, and output line-to-line voltage pulse pattern are also analyzed. The study involves analysis, computer simulations, and detailed laboratory experiments.

APA, Harvard, Vancouver, ISO, and other styles

2

Andrews, Darin M. "Direct torque control of a three-phase voltage source inverter-fed induction machine." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/38872.

Full text

Abstract:

Approved for public release; distribution is unlimited. The scope of this thesis involves various techniques to control the torque of a voltage source inverter-fed induction motor. The three methods investigated here are voltage by frequency, known as scalar control, field-oriented control with and without space vector modulation, and direct torque control. Although all three techniques have been proven effective, each technique possesses its own advantages and disadvantages. In todays engineering world, time and money are saved by utilizing software developed to accurately model a physical system and to compare with hardware previously implemented in a lab. Comparisons can be made to determine how each of these torque control methods perform under static and dynamic modes of operation. The United States military can benefit from this study by modifying or adding onto the software models developed here with little cost and use these models to do trade studies without the cost of lab demonstrations.

APA, Harvard, Vancouver, ISO, and other styles

3

Muhsen, Hani. "Three-Phase Voltage Source Inverter with Very High Efficiency Based on SiC Devices." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-199329.

Full text

Abstract:

This dissertation aims at designing a three-phase voltage source inverter based on the SiC devices and mainly the SiC-MOSFET. The designed inverter offers a possibility to drive the power inverter with a very high efficiency, which can reach up to 99% for 16 kW rated power. The design is dedicated to the electric vehicle application, and it aims at • Providing a comparative study on some of the current discrete SiC devices in terms of the total losses and the thermal conductivity. In addition, a behavioral study of the effective channel mobility with temperature variation in the SiC MOSFET will be investigated. • Designing a gate driver which fits with the driving requirements of the SiC-MOSFET and provides a trade-off between the switching losses and the EMI behavior. • Designing a three-phase voltage source inverter with 16 kW rated power; the design includes minimizing the inverter losses and extracts the EMI model of the power inverter by considering the effects of the parasitic parameters; moreover a short guideline for selecting the heat-sink based on the static network is introduced. • Proposing a new and simplified carried-based PWM, this will reduce the harmonics in the output waveforms and enhance the utilization of the DC-link voltage. • Proposing a new strategy for compensating the dead-time effect in carrier based-PWM and to find out the proper dead-time level in VSI based on SiC –MOSFET. • Designing faults diagnosis and protection circuits in order to protect the power inverter from the common faults; overcurrent, short-circuit, overvoltage, and overtemperature faults.

APA, Harvard, Vancouver, ISO, and other styles

4

Kumar, Rajiv. "Programmed harmonic reduction in single phase and three phase voltage-source inverters." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178302407.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Alskran, Faleh A. "Dynamic modeling and analysis of the three-phase voltage source inverter under stand-alone and grid-tied modes." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18220.

Full text

Abstract:

Master of Science Department of Electrical and Computer Engineering Behrooz Mirafzal Increasing energy demand, rising oil prices, and environmental concerns have forced attention to alternative energy sources that are environmentally friendly and independent of fossil fuels. Renewable energy sources (RES) have become an attractive alternative to the traditional energy sources for electric power generation. However, one of the main challenges of RES adaption arises when connecting RES to the electric grid. Voltage source inverters (VSIs), typically, connect RES to the electric grid. Similar to any engineering system, detailed dynamic models of the VSIs are needed for design and analysis purposes. However, due to the non-linearity of VSIs, development of dynamic models that can accurately describe their behavior is a complex task. In this thesis, a detailed averaged-state-space model of the two-level three-phase space vector pulse width modulation VSI and its companion LCL filter is derived. Because VSIs can operate under stand-alone and grid-tied modes, two models were derived for each case. In the derived models, the VSI modulation index m and phase angle ϕ are initially considered constant. In practice, however, these parameters are considered the main control parameters. To model these parameters as control inputs, small-signal models of the VSI under stand-alone and grid-tied modes were derived. To verify the accuracy of the developed large-signal and small-signal models, Matlab/Simulink simulations were carried out. The simulation results were compared against the models results. Moreover, the models were verified through lab experiments. The developed models can be used as design and analysis tools. In addition, the developed models can be used as fast and efficient simulation tools for system studies, when the modeling of switching transients is not needed. Nowadays, the number of VSIs connected to the electric grid is growing exponentially. The amount of time and computation needed to simulate VSIs using simulation software packages can be significantly decreased by the use of the developed models.

APA, Harvard, Vancouver, ISO, and other styles

6

Chai, Elaina T. "Design, implementation, and verification of a multipurpose, flexible, three-phase back-to-back voltage-source inverter." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91449.

Full text

Abstract:

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014. 16 Cataloged from PDF version of thesis. Includes bibliographical references (pages 87-88). In this thesis, I designed, implemented, and verified a multi-purpose,three-phase back-to- back voltage source inverter for grid connected applications. This inverter features extensive hardware protection, opto-isolation between the power stage and the controller, and reconfigurable I/O routing. The converter is designed for both research and teaching to enable rapid prototyping and verification of advanced control algorithms for grid-connected converters, motor drives etc. I also demonstrate the utility of the power electronics converter as a vector controlled PMSM motor drive. Finally, I use the inverter to perform frequency domain validation of a hardware-in-the-loop simulator. I then design and implement a virtual spectrum analyzer, whose implementation required the creation of a DFT algorithm in python based on the Goertzel algorithm. by Elaina T. Chai. M. Eng.

APA, Harvard, Vancouver, ISO, and other styles

7

Kitson, Joanne. "Shunt regulation of a three-phase voltage bus by means of a bi-directional voltage-fed quasi Z-source inverter." Thesis, University of Bristol, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.761205.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Zhang, Min. "Investigation of switching schemes for three-phase four-leg voltage source inverters." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2319.

Full text

Abstract:

Three-phase four-leg voltage source inverters (VSIs) are widely used in distributed power generation applications, three-phase UPS systems and fault-mode operation of a balanced three-phase system where the balanced three-phase voltage output is required when the loads are unbalanced. A three-dimensional space vector modulation (3-D SVM) switching scheme, which is proved to be compatible with modern DSP implementation for a four-leg VSI, has the advantage of higher DC link utilization, less harmonic contents and less switching losses compared with sinusoidal PWM. Therefore it is the first choice of switching schemes for a four-leg inverter. Electromagnetic interference (EMI) which is associated with common-mode switching for a high voltage level power system can degrade the equipment performance and cause communication problems. The conventional 3-D SVM switching scheme exhibits high common-mode voltage (CMV) characteristics which may result in problems in high power applications. The 3-D SVM has the drawback of being complex which could become a software burden in computationally intense real-time control applications. Attempts to reduce the complexity of the 3-D SVM have been made by many researchers and new switching schemes such as carrier-based PWM proved to have the same performance. This thesis presents a switching scheme called near-state 3-D SVM that can reduce the CMV voltage level of a four-leg inverter by avoiding the use of the two zero switching states of the inverter. A laboratory test bench has been built to validate the proposed switching scheme. An in-depth analysis has been carried out for a four-leg inverter in terms of total harmonic distortion (THD) factor, current harmonic distortion factor, conduction losses and switching losses. The proposed switching scheme is analyzed and compared with the conventional 3-D SVM using the analysis method. Additionally, a simplified switching scheme which is still based on space vector theory is proposed. This simplified switching scheme remains compatible with vector control. Experimental results show that the simplified switching scheme has the same performance as 3-D SVM, with reduced program execution time. Abstract iii An output voltage control loop with current feed-forward term in d-q-0 coordinate, which is designed in the discrete-time domain, proves to be most compatible with a DSP-based control system. Experimental results demonstrate the performance of the control loop in both steady state and transient operation.

APA, Harvard, Vancouver, ISO, and other styles

9

Titiz, Furkan Kaan [Verfasser], Doncker Rik W. [Akademischer Betreuer] De, and Sibylle [Akademischer Betreuer] Dieckerhoff. "A three-phase low-voltage grid-connected current source inverter / Furkan Kaan Titiz ; Rik W. de Doncker, Sibylle Dieckerhoff." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1216040907/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Titiz, Furkan Kaan Verfasser], Doncker Rik W. [Akademischer Betreuer] [De, and Sibylle [Akademischer Betreuer] Dieckerhoff. "A three-phase low-voltage grid-connected current source inverter / Furkan Kaan Titiz ; Rik W. de Doncker, Sibylle Dieckerhoff." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1216040907/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Lugo, Núñez David Rush. "High Power Density and Overcurrent Protection Challenges in the Design of a Three-Phase Voltage Source Inverter for Motor Drive Applications." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/30982.

Full text

Abstract:

The voltage source inverter (VSI) is certainly the most popular topology used in dc to ac power conversion. Virtually every commercial electric motor is driven by a VSI. There is a need for smaller and more efficient drives in high performance applications that is dictating unprecedented power density requirements on airborne motor drive systems. In reply to this need, higher switching frequencies are being sought and new switching devices like Silicon Carbide (SiC) JFETs have emerged. Although faster switching rates favor a reduction in the size of passive components and alleviate the current ripple in the inverter, a penalty is paid on switching losses. Owing to their low switching energy profile, SiC JFETs stand as promising candidates in high switching frequency environments. Their normally-on nature, however, raises a level of discomfort among designers due to the added complexities in the gate drive circuitry and the increased risk of dc bus shoot-through faults in voltage source inverters. Despite of these challenges the use of SiC JFETs continues proliferating in high power density applications. In an effort to study the new challenges introduced by this trend a 2 kW IGBT-based three-phase voltage source inverter operating at 65 kHz was designed, built, and tested. In addition a novel overcurrent protection residing in the inverter dc link is proposed in response to the concern of using normally-on devices in voltage source inverters. Successful hardware validation of both the VSI and the overcurrent protection circuit is supported with experimental results. Master of Science

APA, Harvard, Vancouver, ISO, and other styles

12

Cetin, Nebi Onur. "Design And Implementation Of Advanced Pulse Width Modulation Techniques And Passive Filters For Voltage Source Inverter Driven Three-phase Ac Motors." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612236/index.pdf.

Full text

Abstract:

Advanced pulse width modulation (PWM) techniques such as space vector PWM, active zero state PWM, discontinuous PWM, and near state PWM methods are used in three-phase AC motor drives for the purpose of obtaining low PWM current ripple, wide voltage linearity range, and reduced common mode voltage (CMV). In some applications, a filter is inserted between the inverter and the motor for the purpose of reducing the stresses in the motor. The motor current PWM ripple components, terminal voltage overshoots, shaft voltage, and bearing currents, etc. can all be reduced by means of PWM techniques and passive filters. Various PWM techniques and passive filter types exist. This thesis studies the combinations of PWM techniques and filters and evaluates the performance of the motor drive in terms of the discussed stresses in the motor. PWM techniques are reviewed, a generalized algorithm for the implementation of PWM techniques is developed, and implementation on a 4 kW rated drive is demonstrated. Filter types are studied, among them the common mode inductor and the pure sine filter (PSF) configurations are investigated in detail. Filters are designed and their laboratory performance is evaluated. In the final stage the advanced PWM techniques and filters are combined, the incompatibility problem of discontinuous PWM methods with the PSF is illustrated. A cure based on rate of change limiter is proposed and its feasibility proven in the laboratory experiments. With the use of the proposed PWM algorithm and PSF, a motor drive with ideal DC to AC conversion stage (DC to pure sine) is achieved and its performance is demonstrated in the laboratory.

APA, Harvard, Vancouver, ISO, and other styles

13

Muhsen, Hani [Verfasser], Josef [Akademischer Betreuer] Lutz, and Mario [Gutachter] Pacas. "Three-Phase Voltage Source Inverter with Very High Efficiency Based on SiC Devices / Hani Muhsen ; Gutachter: Mario Pacas ; Betreuer: Josef Lutz." Chemnitz : Universitätsbibliothek Chemnitz, 2016. http://d-nb.info/1213814960/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Tazay, Ahmad F. "Smart Inverter Control and Operation for Distributed Energy Resources." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7097.

Full text

Abstract:

The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. \indent In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1- Low-level control of a single smart Inverter. 2- High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of the microgrid as well as solve specific issues of connecting the microgrid to the system. A detailed procedure for controlling VSC and designing an optimal operation of the controller is also covered in the first part of the dissertation. This section provides an optimal operation for controlling motor drive and demonstrates issues when motor load exists at an autonomous microgrid. It also provides a solution for specific issues at operating a microgrid at autonomous mode as well as improving the structural design for the grid-tied microgrid. The solution for autonomous microgrid includes changing the operational state of the switching pattern of the smart inverter to solve the issue of a common mode voltage (CMV) that appears across the motor load. It also solves the issue of power supplying to large loads, such as induction motors. The last section of the low-level section involves an improvement of the performance and operation of the PV charging station for a plug-in hybrid electric vehicle (PHEV) at grid-tied mode. This section provides a novel structure and smart controller for PV charging station using three-phase hybrid boost converter topology. It also provides a form of applications of a multifunction smart inverter using PV charging station. The second part of the research is focusing on improving the performance of the microgrid by integrating several smart inverters to form a microgrid. It investigates the issue of connecting DER units with the microgrid at real applications. One of the common issues of the microgrid is the circulating current which is caused by poor reactive power sharing accuracy. When more than two DER units are connected in parallel, a microgrid is forming be generating required power for the load. When the microgrid is operated at autonomous mode, all DER units participate in generating voltage and frequency as well as share the load's power. This section provides a smart and novel controlling technique to solve the issue of unequal power sharing. The feature of the smart inverter is realized by the communication link between smart inverters and the main operator. The analysis and derivation of the problem are presented in this section. The dissertation has led to two accepted conference papers, one accepted transaction IEEE manuscript, and one submitted IET transaction manuscript. The future work aims to improve the current work by investigating the performance of the smart inverter at real applications.

APA, Harvard, Vancouver, ISO, and other styles

15

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.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Kwak, Sangshin. "Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2336.

Full text

Abstract:

Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured to stages toward compact realization, increased high-power handling capability, and improving utility interface. Modern ac/ac power converter topologies with various control strategies have been introduced for the further improvements, such as matrix converters, current-fed converters, PWM rectifiers, and active power filters. In this dissertation, several new converter topologies are proposed in conjunction with developed control schemes based on the modern ac/ac converters which enhance performance and solve the drawbacks of conventional converters. In this study, a new fault-tolerant PWM strategy is first proposed for matrix converters. The added fault-tolerant scheme would strengthen the matrix converter technology for aerospace and military applications. A modulation strategy is developed to reshape output currents for continuous operation, against fault occurrence in matrix converter drives. This study designs a hybrid, high-performance ac/ac power converter for high power applications, based on a high-power load commutated inverter and a mediumpower voltage source inverter. Natural commutation of the load commutated inverter is actively controlled by the voltage source inverter. In addition, the developed hybrid system ensures sinusoidal output current/voltage waveforms and fast dynamic response in high power areas. A new topology and control scheme for a six-step current source inverter is proposed. The proposed topology utilizes a small voltage source inverter, to turn off main thyristor switches, transfer reactive load energy, and limit peak voltages across loads. The proposed topology maximizes benefits of the constituent converters: highpower handling capability of large thyristor-based current source inverters as well as fast and easy control of small voltage source inverters. This study analyzes, compares, and evaluates two topologies for unity power factor and multiple ac/ac power conversions. Theoretical analyses and comparisons of the two topologies, grounded on mathematical approaches, are presented from the standpoint of converter kVA ratings, dc-link voltage requirements, switch ratings, semiconductor losses, and reactive component sizes. Analysis, simulation, and experimental results are detailed for each proposed topology.

APA, Harvard, Vancouver, ISO, and other styles

17

Bakkar, Mostafa. "Sag effects on protection system in distributed generation grids." Doctoral thesis, Universitat Politècnica de Catalunya, 2022. http://hdl.handle.net/10803/673721.

Full text

Abstract:

Distributed Generators (DGs) are sensible to voltage sags, so the protection devices must trip fast to disconnect the faulted part of the grid. The DG disconnection will not be desirable in the near future with a large penetration, so it will be necessary to lay down new requirements that should be based on avoiding unnecessary disconnections. Therefore, to prevent unnecessary tripping when inverter-based DGs are connected to the Medium Voltage (MV) grid, reliable and effective protection strategies need to be developed, considering the limited short-circuit current contribution of DG. The initial goal of this study is to employ different possible control strategies for a grid-connected inverter according to the Spanish grid code and to analyze the output voltage behavior during symmetrical and unsymmetrical voltage sags. The analytical development of the proposed strategies shows the impacts of the sag on currents, voltages, active and reactive powers. Another goal of this research is to propose a protection strategy based on Artificial Intelligence for a radial or ring distribution system with high DG penetration. The protection strategy is based on three different algorithms to develop a more secure, redundant, and reliable protection system to ensure supply continuity during disturbances in ring and radial grids without compromising system stability. In order to classify, locate and distinguish between permanent or transient faults, new protection algorithms based on artificial intelligence are proposed in this research, allowing network availability improvement disconnecting only the faulted part of the system. This research introduces the innovative use of directional relay based on a communication system and Artificial Neural Network (ANN). The first algorithm, Centralize algorithm (CE), collects the data from all the PDs in the grid in the centralized controller. This algorithm detects the power flow direction and calculates the positive-sequence current of all the PDs in the grid. Significant benefits of this system are that it consolidates the entire systems security into a single device, which can facilitate system security control. However, the CE will not pinpoint the exact location of the fault if there is any loss of information due to poor communication. Therefore, the systems redundancy can be improved by cooperating with a second algorithm, the Zone algorithm (ZO). ZO algorithm is based on zone control using peer-to-peer connectivity in the same line. The faulty line in that zone may be identified by combining the two PDs data on the same line. The most relevant advantage of this algorithm is its flexibility to adapt to any grid modification or disturbance, even if they are just temporary, unlike the CE, which is fixed to the existing grid configuration. The third protection algorithm, Local algorithm (LO), has been proposed without depending on the communication between the PDs; then, the protection system can work properly in case of a total loss of communication. Each PD should be able to detect if the fault is located in the protected line or another line by using only the local information of the PD. According to the type of fault and based on local measurements at each PD of abc voltages and currents, different algorithms will be applied depending on the calculation of the sequence components. The main advantage of this algorithm is the separate decision of each PD, and avoiding communication problems. In case of radial grids, both mechanical breakers and Solid State Relays (SSRs) are used to verify the protection strategies, and in the case of ring grids, mechanical breakers are used, due to the limitations in required voltage difference of SSR. The proposed protection algorithms are compared with conventional protections (Overcurrent and Differential) protections to validate the contribution of the proposed algorithms, especially in reconfigurable smart grids. El objetivo inicial de este estudio es emplear diferentes estrategias de control posibles para un inversor conectado a la red segun el código de red español y analizar el comportamiento de la tensión de salida durante caídas de tensión simétricas y asimétricas. El desarrollo analítico de las estrategias propuestas muestra los impactos de los huecos de tensión en las corrientes, tensiones, potencias activas y reactivas. Otro objetivo de esta investigación es proponer una estrategia de protecclón basada en lnteligencia Artificial para una red del Sistema de Distribución, radial o en anillo, con elevada penetración de Generación Distribuida. La estrategia de protección se basa en tres algoritmos diferentes para desarrollar un sistema de protección más seguro, redundante, y fiable, que asegure la continuidad de suministro durante perturbaciones en redes radiales o en anillo sin comprometer la estabilidad del sistema. Para clasificar, localizar y distinguir entre faltas permanentes o transitorias, se proponen en este trabajo nuevos algoritmos de protección basados en inteligencia artificial, permitiendo la mejora de la disponibilidad de la red, al desconectar sólo la parte del sistema en falta. Esta investigación introduce la innovación del uso del rele direccional basado en un sistema de comunicación y Redes Neuronales Artificiales (ANN). El primer algoritmo, Algoritmo Central (CE), recibe los datos de todos los PDs de la red en un control central. Este algoritmo detecta la dirección de flujo de cargas y calcula la corriente de secuencia positiva de todos los PDs de la red. El entrenamiento de ANNs incluye variaciones en la corriente de cortocircuito y la dirección del flujo de potencia en cada PD. Los beneficios mas significativos de este sistema son que concentra la seguridad total del sistema en un único dispositivo, lo que puede facilitar el control de la seguridad del sistema. Sin embargo, el CE no determinara con precisión la localización exacta de la falta si hay alguna perdida de información debida a una pobre comunicación. Por lo tanto, la redundancia del sistema se puede mejorar cooperando con un segundo algoritmo, el algoritmo de Zona (ZO). El algoritmo ZO se basa en un control de zona usando la conectividad entre dispositivos de protección de una misma línea. La línea en falta en esa zona puede identificarse combinando los datos de los dos PDs de la misma línea.. La ventaja mas relevante de este algoritmo es su flexibilidad para adaptarse a cualquier modificación de la red o perturbación, incluso si sólo son temporales, a diferencia del CE, que se ha adaptado para la configuración de la red existente. El tercer algoritmo de protección, algoritmo Local (LO), ha sido propuesto sin dependencia de la comunicación entre PDs; por lo tanto, el sistema de protección puede operar correctamente en el caso de una pérdida total de comunicación. Cada PD debe poder detectar si la falta esta ubicada en la línea protegida o en otra línea, utilizando sóIo la información local del PD. Según el tipo de falta, y en base a medidas locales en cada PD, de tensiones y corrientes abc, se aplican diferentes algoritmos en función del cálculo de las componentes simétricas. La principal ventaja de este algoritmo es la actuación por separado de cada PD, evitando los problemas de comunicación. En el caso de las redes radiales, se utilizan tanto interruptores mecánicos como réles de estado sóIido (SSR) para verificar las estrategias de protección, y en el caso de las redes en anillo se utilizan interruptores mecánicos, debido a las limitaciones de tensión para su conexión. Los algoritmos de protección propuestos se comparan con protecciones convencionales (Sobrecorriente y Diferencial) para validar la contribución de los algoritmos propuestos, especialmente en redes inteligentes reconfigurables. Enginyeria Elèctrica

APA, Harvard, Vancouver, ISO, and other styles

18

Garnica, López Miguel Andrés. "Control of grid-connected three-phase three-wire voltage-sourced inverters under voltage disturbances." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/664934.

Full text

Abstract:

The present doctoral thesis focuses on designing control schemes for three-phase three-wire voltage-sourced inverters connected to the grid under voltage disturbances. The research recognizes the large-scale integration of distributed power generation systems into the network and takes advantage of this circumstance to investigate and develop new control strategies in order to provide better support to the modern power grid. As a first contribution, a new algorithm to maximize power delivery capability of the inverter has been developed and experimentally tested under voltage imbalance conditions, i.e., during slight/shallow and deep asymmetrical sags. The algorithm of this control strategy meets grid code requirements, performs active power control, limits the maximum current injected by the inverter, and eliminates active power oscillations. As a result, six different cases of current injection were identified in this work, considering restrictions imposed by grid codes as well as different active-power production scenarios. The second contribution of this research work has provided an experimental analysis of a low-voltage ride-through strategy whose voltage support capability had not been tested when voltage sags occur. This study was performed considering a scenario of multiple grid-connected inverters, different profiles of active power injection, and the equivalent grid impedance seen from the output side of each converter. In the third contribution has been proposed a closed-loop controller for low-power distributed inverters that maximizes the current injection when voltage sag occurs. The control algorithm has been designed to meet grid code requirements and avoid overvoltage in non-faulty phases during grid faults. The controller is responsible for meeting coordinately several objectives and addressing the interactions that appear among them. In the last two chapters, the argument of this doctoral thesis is complemented, the obtained experimental results are globally analyzed, finally, the present research work is concluded. Esta tesis doctoral, presentada en la modalidad de compendio de publicaciones en cumplimiento parcial de los requisitos para optar al título de Doctor en Ingeniería Electrónica de la Universidad Politécnica de Cataluña, se centra en el diseño de esquemas de control para inversores trifásicos conectados a la red eléctrica durante perturbaciones de voltaje. La investigación reconoce la integración a gran escala de los sistemas de generación distribuida en la red y aprovecha esta circunstancia para estudiar y desarrollar nuevas estrategias de control con el propósito de brindar un mejor soporte a la red eléctrica moderna. Como primera contribución, se desarrolló un nuevo algoritmo para maximizar la capacidad de suministro de potencia del inversor en condiciones de desequilibrio de voltaje, es decir, durante caídas asimétricas de tensión leves, poco profundas y severas. El algoritmo de esta estrategia de control fue diseñado para cumplir los requerimientos de los vigentes códigos de red (grid codes), realizar control de la potencia activa, limitar la corriente máxima inyectada por el inversor y eliminar las oscilaciones de la potencia activa instantánea. Como resultado, en esta investigación se identificaron y validaron experimentalmente seis casos diferentes de inyección de corriente en la red, trabajo que tuvo en cuenta no solo las restricciones impuestas por los códigos de red, sino también los diferentes escenarios de producción de potencia activa. La segunda contribución de este trabajo de investigación ha proporcionado el análisis experimental de una estrategia de inyección de corriente cuya capacidad de soporte de voltaje no se había probado durante fallos de red. Este estudio se realizó sobre un escenario de múltiples inversores conectados a la red eléctrica, utilizando diferentes perfiles de inyección de potencia activa y considerando, como aspecto fundamental para el análisis experimental, la impedancia de red equivalente vista desde el lado de salida de cada convertidor. En la tercera contribución se diseñó un controlador en lazo cerrado para inversores distribuidos de baja potencia que maximiza la inyección de corriente cuando se produce una caída de tensión. Este algoritmo de control también satisface los requerimientos de los actuales códigos de red en cuanto a inyección de corriente reactiva durante fallos de red, pero cuenta con la capacidad adicional de evitar sobretensiones en las fases no defectuosas. De igual forma, este controlador es responsable de acometer coordinadamente varios objetivos y gestionar las interacciones que aparecen entre ellos. En los últimos dos capítulos se complementa la unidad temática de esta tesis doctoral, se analizan globalmente los resultados experimentales obtenidos y, finalmente, se concluye el presente trabajo de investigación agregando, también, futuros campos de estudio.

APA, Harvard, Vancouver, ISO, and other styles

19

Amadasu, Henry O. "Development of three-phase source inverter for research and laboratories." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5816.

Full text

Abstract:

Approved for public release; distribution is unlimited. s focused on in this thesis. The development of a three-phase VSI, the thermal and power loss analysis of a three-phase VSI and the hardware interface between the FPGA and the three-phase VSI used for research and laboratory procedures at NPS are particularly concentrated on.

APA, Harvard, Vancouver, ISO, and other styles

20

Jacobs, D. M. (Danver Maxwill). "Voltage control of medium to high power three-phase inverter supply systems." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52608.

Full text

Abstract:

Thesis (MScEng)--University of Stellenbosch, 2001. ENGLISH ABSTRACT: In this thesis a new voltage control method is developed for a three-phase inverter supply system. The inverter supply system consist of a Permanent Magnet Generator, a three-phase rectifier, a three-phase inverter plus LC-filter and a three-phase transformer in series. This system supplies power to a network or to a stand-alone load. The main focus of this thesis is on the control aspects of the inverter and the LC-filter. Different voltage control systems are investigated and compared to each other. From these methods the proposed voltage control method is developed where only the output voltages are measured to establish good voltage control. All these voltage control methods are also simulated with a software package. The proposed voltage control method compares very well with other voltage control methods. The results that are obtained in the simulations are satisfactory. The proposed voltage control method is also implemented in an 8 kW laboratory scale model and, again, very good practical results are obtained. A TMS320F240 nsp controller is used to implement the proposed voltage control method. The controller compensates well for load steps, and these results compare well to an alternative voltage control method, which was also evaluated practically. AFRIKAANSE OPSOMMING: In hierdie tesis IS 'n nuwe spanningsbeheermetode ontwikkel VIr 'n drie-fase wisselrigter kragtoevoerstelsel. Die wisselrigter kragtoevoerstelsel bestaan uit 'n Permanent Magneet Generator, 'n drie-fase gelykrigter, 'n drie-fase wisselrigter plus Le-filter, en 'n drie-fase transformator in serie. Hierdie stelsel voorsien krag aan 'n netwerk sowel as aan 'n alleenstaande las. Die hooffokus van hierdie tesis is op die beheeraspekte van die wisselrigter en Le-filter. Verskillende spanningsbeheermetodes is deeglik ondersoek en vergelyk met mekaar. Uit hierdie metodes is dan die voorgestelde beheermetode ontwikkel waar slegs die uittreespanning gemeet word om goeie spanningsbeheer te kan doen. Al hierdie spanningsbeheermetodes is dan gesimuleer met 'n sagteware pakket. Die voorgestelde spanningsbeheermetode vergelyk baie goed met die ander spanningsbeheermetodes. Die resultate verky in die simulasies is ook baie bevredigend. Die voorgestelde beheermetode is ook geïmplementeer op 'n 8 kW laboratorium skaalmodel en weereens is baie goeie praktiese resultate verky. 'n TMS320F240 DSP-beheerder is gebruik om die voorgestelde beheermetode mee te implementeer. Die beheerder kompenseer baie goed vir lastrappe en vergelyk ook goed met 'n ander spanningsbeheermetode wat prakties ge-evalueer is.

APA, Harvard, Vancouver, ISO, and other styles

21

Zhang, Di. "Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/27579.

Full text

Abstract:

Three-phase voltage source converters(VSCs) have become the converter of choice in many ac medium and high power applications due to their many advantages, including low harmonics, high power factor, and high efficiency. Modular VSCs have also been a popular choice as building blocks to achieve even higher power, primarily through converter paralleling. In addition to high power ratings, paralleling converters can also provide system redundancy through the so-called (N+1) configuration for improved availability, as well as allow easy implementation of converter power management. Interleaving can further improve the benefit of paralleling VSCs by reducing system harmonic currents, which potentially can increase system power density. There are many challenges to implement interleaving in paralleled VSCs system due to the complicated relationships in a three-phase power converter system. In addition, to maximize the benefit of interleaving, current knowledge of symmetric interleaving is not enough. More insightful understanding of this PWM technology is necessary before implement interleaving in a real paralleled VSCs system. In this dissertation, a systematic methodology to analyze and design a paralleled three-phase voltage source converters with interleaving is developed. All the analysis and proposed control methods are investigated with the goal of maximizing the benefit of interleaving based on system requirement. The dissertation is divided into five sections. Firstly, a complete analysis studying the impact of interleaving on harmonic currents in ac and dc side passive components for paralleled VSCs is presented. The analysis performed considers the effects of modulation index, pulse-width-modulation (PWM) schemes, interleaving angle and displacement angle. Based on the analysis the method to optimize interleaving angle is proposed. Secondly, the control methods for the common mode (CM) circulating current of paralleled three-phase VSCs with discontinuous space-vector modulation (DPWM) and interleaving are proposed. With the control methods, DPWM and interleaving, which is a desirable combination, but not considered possible, can be implemented together. In addition, the total flux of integrated inter-phase inductor to limit circulating current can be minimized. Thirdly, a 15 kW three phase ac-dc rectifier is built with SiC devices. With the technologies presented in this dissertation, the specific power density can be pushed more than 2kW/lb. Fourthly, the converter system with low switching frequency is studied. Special issues such as beat phenomenon and system unbalance due to non-triplen carrier ratio is explained and solved by control methods. Other than that, an improved asymmetric space vector modulation is proposed, which can significantly reduce output current total harmonic distortion (THD) for single and interleaved VSCs system. Finally, the method to protect a system with paralleled VSCs under the occurrence of internal faults is studied. After the internal fault is detected and isolated, the paralleled VSCs system can continue work. So system reliability can be increased. Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

22

Cuadros, O. Carlos E. "Modified Space Vector Modulation for a Zero-Voltage Transition Three-Phase to DC Bi-directional Converter." Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/36712.

Full text

Abstract:

A modified space vector modulation algorithm for a zero-voltage transition three-phase voltage source inverter/boost rectifier is presented. The converter is intended for high performance medium power applications requiring bi-directional power flow. The proposed modified space vector modulation allows the main switches to be operated with constant frequency and soft switching for any phase shift between the three-phase currents and voltages. The modulation algorithm also eliminates any low frequency distortion caused by the zero-voltage transition and can be extended to other soft-switching PWM three-phase converters. Experimental verification of the proposed algorithm is also presented as well as a comparison to the hard switched PWM converter. Master of Science

APA, Harvard, Vancouver, ISO, and other styles

23

Alves, rodrigues Luis Gabriel. "Design and characterization of a three-phase current source inverter using 1.7kV SiC power devices for photovoltaic applications." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT030.

Full text

Abstract:

Classiquement, la chaîne de conversion de l’énergie électrique des centrales photovoltaïques comporte un champ photovoltaïque (PV) délivrant une tension maximale de 1kV suivi d’un hacheur élévateur connecté à un onduleur de tension triphasé. Cette chaîne de conversion à deux étages (DC/DC + DC/AC) est ensuite raccordée sur le réseau moyenne tension au travers d’un transformateur BT/HTA. Dans l’objectif de simplifier les systèmes de conversion PV, ce travail de recherche s’intéresse à l’étude et la mise en œuvre d’une topologie DC/AC n’employant qu’un seul étage de conversion : l’Onduleur de Courant triphasé. Bien que relativement simple, l’Onduleur de Courant présente comme inconvénient majeur les pertes par conduction. Pour pallier ce problème, des interrupteurs à grand-gap au Carbure de Silicium (SiC) sont employés, ce qui permet de convertir de l’énergie de façon performante (η>98.5%) tout en gardant une fréquence de commutation élevée (plusieurs dizaines de kHz). Les modules à semi-conducteurs de puissance du marché n’étant pas compatibles avec ce type de convertisseur, des modules particuliers en SiC ont été développés dans le cadre de la thèse. La caractérisation dynamique de ces nouveaux modules est réalisée dans le but de servir de base à la conception d’un démonstrateur de l’Onduleur de Courant d’une puissance nominale de 60kW. Enfin, le rendement de la partie semi-conducteur de puissance est évalué par une méthode calorimétrique confirmant l’aptitude de la topologie à fonctionner à des fréquences de commutation supérieures. L’originalité de ces travaux réside principalement dans la conception, caractérisation et mise en œuvre de ce nouveau module de puissance adapté à cette topologie connue, mais peu étudiée à l’heure actuelle avec des interrupteurs au SiC Classically, the energy conversion architecture found in photovoltaic (PV) power plants comprises a multitude of solar arrays delivering a maximum voltage of 1kV followed by a step-up chopper connected to a three-phase voltage source inverter. This two-stage conversion system (DC/DC + DC/AC) is then connected to the MV grid through a LV/MV transformer. In order to simplify the PV systems, this research work focuses on the study and implementation of a DC/AC topology employing a single conversion stage: the three-phase current source inverter (CSI). Although relatively simple, the CSI presents as major drawback the conduction losses. To deal with this problem, wide-bandgap silicon carbide (SiC) semiconductors are used, which allows to efficiently convert energy (η> 98.5%) while keeping a relatively high switching frequency (several tens of kHz). Nonetheless, since the available power semiconductor modules on the market are not compatible with the CSI, a novel 1.7kV SiC-based module is developed in the context of the thesis. Thus, the dynamic characterization of the new SiC device is carried out and serves as a basis for the design of a 60kW Current Source Inverter prototype. Finally, the inverter’s semiconductor efficiency is evaluated through a calorimetric method, confirming the ability of the topology to operate at higher switching frequencies. At the present time, little research has been conducted on the CSI implementation with SiC devices. The originality of this work lies mainly in the design, characterization and implementation of the new SiC power module adapted to this well-known inverter topology

APA, Harvard, Vancouver, ISO, and other styles

24

Afiat, Milani Alireza. "Voltage regulation in a single-stage three-phase boost-inverter using modified phasor pulse width modulation method for stand-alone applications." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16219.

Full text

Abstract:

Master of Science Department of Electrical and Computer Engineering Behrooz Mirafzal In this thesis, a modified version of the phasor pulse width modulation (PPWM) switching method for use in a single-stage three-phase boost inverter is presented. Because of the required narrow pulses in the PPWM method and limitations in controller resolution, e.g. dSPACE, the desired switching pattern for a boost inverter requires a costly processor. A low resolution processor can cause pulse dropping which results in some asymmetric conditions in output waveforms of the boost inverter and therefore, an increase in the THD of the output waveform. In order to solve this problem, a new switching pattern is developed which guarantees symmetric conditions in the switching pattern by discretizing the switching pattern in every switching cycle. This switching pattern has been applied to a boost inverter model developed by SimPowerSystems toolbox of MATLAB/Simulink. The model has been simulated in a wide range of input DC voltage and load. Moreover, a laboratory-scaled three-phase boost inverter has been designed, built, and tested using an identical switching pattern in the same input voltage and load range. Both simulation and experimental results confirm the effectiveness of the new switching pattern.

APA, Harvard, Vancouver, ISO, and other styles

25

Demirkutlu, Eyyup. "Output Voltage Control Of A Four-leg Inverter Based Three-phase Ups By Means Of Stationary Frame Resonant Filter Banks." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608151/index.pdf.

Full text

Abstract:

A method for high performance output voltage control of a four-leg inverter based three-phase transformerless UPS is proposed. Voltage control loop is employed and the method employs stationary frame resonant filter controllers for the fundamental and harmonic frequency components. A capacitor current feedback loop provides active damping and enhances the output voltage dynamic performance. The controller design and implementation details are given. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steadystate and dynamic performance of the UPS are investigated in detail. A scalar PWM method with implementation simplicity and high performance is proposed and implemented. The control and PWM methods are proven by means of theory, simulations, and experiments.

APA, Harvard, Vancouver, ISO, and other styles

26

Pou, Félix Josep. "Modulation and control of three-phase PWM multilevel converters." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/6327.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

27

Cetinkaya, Suleyman. "Repetitive Control Of A Three-phase Uninterruptible Power Supply With Isolation Transformer." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608150/index.pdf.

Full text

Abstract:

A repetitive control method for output voltage control of a three phase uninterruptible power supply (UPS) with isolation transformer is investigated. In the method voltage control loop is employed in the stationary dq frame. The controller eliminates the periodic errors on the output voltages due to inverter voltage nonlinearity and load disturbances. The controller design and implementation details are given. The controller is implemented on a 5-kVA UPS prototype which is constructed in laboratory. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steady-state and dynamic performance of the control method are investigated in detail. The theory of the control strategy is verified by means of simulations and experiments.

APA, Harvard, Vancouver, ISO, and other styles

28

Macík, Tomáš. "Model trojfázové umělé sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413220.

Full text

Abstract:

The Diploma thesis deals with control of three-phase active rectifier and a three-phase DC/AC converter. It also explains phase-locked loop principle. The theoretical part including first three chapters lists several control approaches to three phase active rectifier and three phase DC/AC converter. Described control approaches to the active rectifier are control in dq frame and control in dq UVW frame. Listed control approaches to the DC/AC converter include cascaded control structure and a full state feedback control. The practical part is divided into last three chapters and includes mathematical description of phase-locked loop principle, model of active rectifier controlled in dq frame and a model of DC/AC converter controlled both by a cascaded control and a full¬ state feedback. The models are created in Matlab Simulink.

APA, Harvard, Vancouver, ISO, and other styles

29

Aboelhassan, Mustafa Osman Elrayah. "Robustní řízení synchronního stroje s permanentními magnety a spínaným tokem." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-233605.

Full text

Abstract:

Je jasné, že nejúspěšnější konstrukce zahrnuje postup vícefázového řízení, ve kterém každá fáze může být považována za samostatný modul. Provoz kterékoliv z jednotek musí mít minimální vliv na ostatní, a to tak, že v případě selhání jedné jednotky ostatní mohou být v provozu neovlivněny. Modulární řešení vyžaduje minimální elektrické, magnetické a tepelné ovlivnění mezi fázemi řízení (měniče). Synchronní stroje s pulzním tokem a permanentními magnety se jeví jako atraktivní typ stroje, jejíž přednostmi jsou vysoký kroutící moment, jednoduchá a robustní konstrukce rotoru a skutečnost, že permanentní magnety i cívky jsou umístěny společně na statoru. FS-PMSM jsou poměrně nové typy střídavého stroje stator-permanentní magnet, které představují významné přednosti na rozdíl od konvenčních rotorů - velký kroutící moment, vysoký točivý moment, v podstatě sinusové zpětné EMF křivky, zároveň kompaktní a robustní konstrukce díky umístění magnetů a vinutí kotvy na statoru. Srovnání výsledků mezi FS-PMSM a klasickými motory na povrchu upevněnými PM (SPM) se stejnými parametry ukazuje, že FS-PMSM vykazuje větší vzduchové mezery hustoty toku, vyšší točivý moment na ztráty v mědi, ale také vyšší pulzaci díky reluktančnímu momentu. Pro stroje buzené permanentními magnety se jedná o tradiční rozpor mezi požadavkem na vysoký kroutící moment pod základní rychlostí (oblast konstantního momentu) a provozem nad základní rychlostí (oblast konstantního výkonu), zejména pro aplikace v hybridních vozidlech. Je předložena nová topologie synchronního stroje s permanentními magnety a spínaným tokem odolného proti poruchám, která je schopná provozu během vinutí naprázdno a zkratovaného vinutí i poruchách měniče. Schéma je založeno na dvojitě vinutém motoru napájeném ze dvou oddělených vektorově řízených napěťových zdrojů. Vinutí jsou uspořádána takovým způsobem, aby tvořila dvě nezávislé a oddělené sady. Simulace a experimentální výzkum zpřesní výkon během obou scénářů jak za normálního provozu, tak za poruch včetně zkratových závad a ukáží robustnost pohonu za těchto podmínek. Tato práce byla publikována v deseti konferenčních příspěvcích, dvou časopisech a knižní kapitole, kde byly představeny jak topologie pohonu a aplikovaná řídící schémata, tak analýzy jeho schopnosti odolávat poruchám.

APA, Harvard, Vancouver, ISO, and other styles

30

Qi, Feng. "Peripheral Circuits Study for High Temperature Inverters Using SiC MOSFETs." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460991531.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Ivan, Todorović. "Управљање претварачем којим се остварује подршка дистрибутивној мрежи током поремећаја". Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107815&source=NDLTD&language=en.

Full text

Abstract:

Предложен контролни алгоритам за инвертор повезан на мрежуомогућава реализацију сваког профила контролисаних електричнихвеличина који је у домену физичких могућности дистрибуираног извора.Другим речима, управљачки програм не обезбеђује остваривањедискретног спектра режима, као што је то до сада био случај сарешењима предложеним у научној литератури, већ омогућава сигурнупроизводњу произвољног профила фазних струја и напона. Показано једа предложено решење задовољава најстроже релевантне законскерегулативе. У раду је анализиран већи број функционалности и испитанје њихов утицај на процес производње електричне енергије с акцентом нахаваријске режиме. Разматрана је интеракција дистрибуираних изво-ра идистрибутивне мреже у режимима са поремећајима и приложен је већиброј експерименталних резултата прикупљених употребом HIL окружења. Predložen kontrolni algoritam za invertor povezan na mrežuomogućava realizaciju svakog profila kontrolisanih električnihveličina koji je u domenu fizičkih mogućnosti distribuiranog izvora.Drugim rečima, upravljački program ne obezbeđuje ostvarivanjediskretnog spektra režima, kao što je to do sada bio slučaj sarešenjima predloženim u naučnoj literaturi, već omogućava sigurnuproizvodnju proizvoljnog profila faznih struja i napona. Pokazano jeda predloženo rešenje zadovoljava najstrože relevantne zakonskeregulative. U radu je analiziran veći broj funkcionalnosti i ispitanje njihov uticaj na proces proizvodnje električne energije s akcentom nahavarijske režime. Razmatrana je interakcija distribuiranih izvo-ra idistributivne mreže u režimima sa poremećajima i priložen je većibroj eksperimentalnih rezultata prikupljenih upotrebom HIL okruženja. Proposed grid-connected inverter control algorithm enables production of anycontrolled variables’ profile that is in the domain of converter’s physicalcapabilities. In other words, the control program does not allow only for anarrow spectrum of different working regimes to be realized, as it was the casepreviously with the solutions proposed in the literature, but can result in a safeproduction of arbitrary meaningful phase currents and voltages profiles. It wasdemonstrated that the proposed solution satisfies the most stringent of the GridCodes. Furthermore, advanced functionalities not addressed in the Grid Codeswere also analysed and the influence of those functionalities’ application onthe process of the energy production during the grid faults was evaluated inthe dissertation. Interaction between the distributed generation units and thedistribution network was studied and a number of HIL experimental results areprovided.

APA, Harvard, Vancouver, ISO, and other styles

32

Lobato, Salatiel de Castro. "Fonte de corrente para aplicação em magnetos de aceleradores de partículas." Universidade Federal de Juiz de Fora (UFJF), 2016. https://repositorio.ufjf.br/jspui/handle/ufjf/3646.

Full text

Abstract:

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-13T15:20:14Z No. of bitstreams: 1 salatieldecastrolobato.pdf: 51678452 bytes, checksum: 022776c88833a1e47901180ebd1f826b (MD5) Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-13T19:33:17Z (GMT) No. of bitstreams: 1 salatieldecastrolobato.pdf: 51678452 bytes, checksum: 022776c88833a1e47901180ebd1f826b (MD5) Made available in DSpace on 2017-03-13T19:33:17Z (GMT). No. of bitstreams: 1 salatieldecastrolobato.pdf: 51678452 bytes, checksum: 022776c88833a1e47901180ebd1f826b (MD5) Previous issue date: 2016-11-07 O objetivo geral desta dissertação é o aperfeiçoamento do projeto de uma nova fonte de corrente em desenvolvimento para o acelerador de partículas Sirius. A corrente da fonte é aplicada em magnetos de elevada indutância e são programadas para apresentar forma de onda com signiﬁcativa componente senoidal em corrente contínua e em baixa frequência, de acordo com as características operacionais necessárias do Sirius. Para efeitos de estudo, a metodologia empregada consiste essencialmente em desacoplar a análise e o projeto do controle em um estágio regulador de tensão seguido de um estágio de síntese da corrente. Foram realizados ensaios em uma fonte em construção no Laboratório Nacional de Luz Síncroton e em um protótipo desenvolvido na UFJF. As principais contribuições descritas nesta dissertação são: i) atenuação da propagação de distúrbios de baixa frequência para a rede elétrica; ii) emprego de retiﬁcador de tensão controlado para regulação da tensão do barramento CC, melhoria do fator de potência e redução de componentes harmônicas. Os resultados experimentais evidenciam que as alterações de projeto propostas nesta dissertação apresentam grande potencial para melhorar o desempenho da fonte de corrente em termos da qualidade de energia elétrica e da sintetização de corrente senoidal no magneto do acelerador de partículas. This work consists in the evaluation and improvement of a current source for a particle accelerator. The output current presents a DC sinusoidal waveform in low frequecy which ﬂows through the windings of high inductance electromagnets. The methodology consists in separating the analysis and project of the control into two parts: a voltage regulator stage,followedbyacurrentsynthesisstage. Testswereperformedonacurrentsourceunder construction at the Brazilian Synchrotron Light Laboratory (LNLS) and on a prototype developed at UFJF. The work main contributions are: i) Attenuation of the low frequency disturbances on the electrical grid; ii) Use of a controlled rectiﬁer to regulate the voltage of the DC bus, improvement in power factor and reduction of harmonic components. The experimental results show that the proposed changes have potential in improving the performace of the current source in terms of its electric power quality and synthesis of sinusoidal current in the particule accelerator.

APA, Harvard, Vancouver, ISO, and other styles

33

Jung, Jin Woo. "Modeling and control of fuel cell based distributed generation systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1116451881.

Full text

Abstract:

Thesis (Ph. D.)--Ohio State University, 2005. Title from first page of PDF file. Document formatted into pages; contains xvi, 209 p.; also includes graphics. Includes bibliographical references (p. 202-209). Available online via OhioLINK's ETD Center

APA, Harvard, Vancouver, ISO, and other styles

34

Zare, Firuz. "Multilevel converter structure and control." Thesis, Queensland University of Technology, 2001. https://eprints.qut.edu.au/36142/7/36142_Digitsed%20Thesis.pdf.

Full text

Abstract:

In recent years, multilevel converters are becoming more popular and attractive than traditional converters in high voltage and high power applications. Multilevel converters are particularly suitable for harmonic reduction in high power applications where semiconductor devices are not able to operate at high switching frequencies or in high voltage applications where multilevel converters reduce the need to connect devices in series to achieve high switch voltage ratings. This thesis investigated two aspects of multilevel converters: structure and control. The first part of this thesis focuses on inductance between a DC supply and inverter components in order to minimise loop inductance, which causes overvoltages and stored energy losses during switching. Three dimensional finite element simulations and experimental tests have been carried out for all sections to verify theoretical developments. The major contributions of this section of the thesis are as follows: The use of a large area thin conductor sheet with a rectangular cross section separated by dielectric sheets (planar busbar) instead of circular cross section wires, contributes to a reduction of the stray inductance. A number of approximate equations exist for calculating the inductance of a rectangular conductor but an assumption was made that the current density was uniform throughout the conductors. This assumption is not valid for an inverter with a point injection of current. A mathematical analysis of a planar bus bar has been performed at low and high frequencies and the inductance and the resistance values between the two points of the planar busbar have been determined. A new physical structure for a voltage source inverter with symmetrical planar bus bar structure called Reduced Layer Planar Bus bar, is proposed in this thesis based on the current point injection theory. This new type of planar busbar minimises the variation in stray inductance for different switching states. The reduced layer planar busbar is a new innovation in planar busbars for high power inverters with minimum separation between busbars, optimum stray inductance and improved thermal performances. This type of the planar busbar is suitable for high power inverters, where the voltage source is supported by several capacitors in parallel in order to provide a low ripple DC voltage during operation. A two layer planar busbar with different materials has been analysed theoretically in order to determine the resistance of bus bars during switching. Increasing the resistance of the planar busbar can gain a damping ratio between stray inductance and capacitance and affects the performance of current loop during switching. The aim of this section is to increase the resistance of the planar bus bar at high frequencies (during switching) and without significantly increasing the planar busbar resistance at low frequency (50 Hz) using the skin effect. This contribution shows a novel structure of busbar suitable for high power applications where high resistance is required at switching times. In multilevel converters there are different loop inductances between busbars and power switches associated with different switching states. The aim of this research is to consider all combinations of the switching states for each multilevel converter topology and identify the loop inductance for each switching state. Results show that the physical layout of the busbars is very important for minimisation of the loop inductance at each switch state. Novel symmetrical busbar structures are proposed for multilevel converters with diode-clamp and flying-capacitor topologies which minimise the worst case in stray inductance for different switching states. Overshoot voltages and thermal problems are considered for each topology to optimise the planar busbar structure. In the second part of the thesis, closed loop current techniques have been investigated for single and three phase multilevel converters. The aims of this section are to investigate and propose suitable current controllers such as hysteresis and predictive techniques for multilevel converters with low harmonic distortion and switching losses. This section of the thesis can be classified into three parts as follows: An optimum space vector modulation technique for a three-phase voltage source inverter based on a minimum-loss strategy is proposed. One of the degrees of freedom for optimisation of the space vector modulation is the selection of the zero vectors in the switching sequence. This new method improves switching transitions per cycle for a given level of distortion as the zero vector does not alternate between each sector. The harmonic spectrum and weighted total harmonic distortion for these strategies are compared and results show up to 7% weighted total harmonic distortion improvement over the previous minimum-loss strategy. The concept of SVM technique is a very convenient representation of a set of three-phase voltages or currents used for current control techniques. A new hysteresis current control technique for a single-phase multilevel converter with flying-capacitor topology is developed. This technique is based on magnitude and time errors to optimise the level change of converter output voltage. This method also considers how to improve unbalanced voltages of capacitors using voltage vectors in order to minimise switching losses. Logic controls require handling a large number of switches and a Programmable Logic Device (PLD) is a natural implementation for state transition description. The simulation and experimental results describe and verify the current control technique for the converter. A novel predictive current control technique is proposed for a three-phase multilevel converter, which controls the capacitors' voltage and load current with minimum current ripple and switching losses. The advantage of this contribution is that the technique can be applied to more voltage levels without significantly changing the control circuit. The three-phase five-level inverter with a pure inductive load has been implemented to track three-phase reference currents using analogue circuits and a programmable logic device.

APA, Harvard, Vancouver, ISO, and other styles

35

KUMAR, HEMANT. "MITIGATION OF T.H.D OF MICRO CONTROLLER BASED THREE PHASE VOLTAGE SOURCE INVERTER." Thesis, 2019. http://dspace.dtu.ac.in:8080/jspui/handle/repository/17054.

Full text

Abstract:

The use of power electronic devices plays a crucial role in control and transformation of electrical power.These devices are non-linear which takes enough space in all the regions of Power electronic converters. Inverter plays important role in industrial and domestic- applications for converting the direct current(DC) power into an alternating current(AC) power. Use of these controlled switches in inverters is gives a smooth and precise control for the transformation of electric power. But on the other hand, usage of these controlled switches results in the high level of Total Harmonic Distortion (THD) which has poor effects on the converter’s performance. This thesis aims at the mitigation of THD for three-phase voltage source inverter using low pass filter. This method is analyzed using fourier spectrum of the output phase voltages and the total harmonic distortion (THD). With addition to this, this thesis also discusses three phase inverter with 180 and 120 degrees conduction mode. RLC low pass filter is designed to reduce the lower order dominating harmonics and to lowers the total harmonic distortion (THD). The models for boost converter, gate driver circuit three phase inverter with 180 and 120 degrees conduction mode (with and without filter) have been simulated using proteus (simulator) and 8051 microcontroller is programmed using uKeil (programming software) to control the switching pattern of MOSFET’s.

APA, Harvard, Vancouver, ISO, and other styles

36

Muhsen, Hani. "Three-Phase Voltage Source Inverter with Very High Efficiency Based on SiC Devices." Doctoral thesis, 2015. https://monarch.qucosa.de/id/qucosa%3A20425.

Full text

Abstract:

This dissertation aims at designing a three-phase voltage source inverter based on the SiC devices and mainly the SiC-MOSFET. The designed inverter offers a possibility to drive the power inverter with a very high efficiency, which can reach up to 99% for 16 kW rated power. The design is dedicated to the electric vehicle application, and it aims at • Providing a comparative study on some of the current discrete SiC devices in terms of the total losses and the thermal conductivity. In addition, a behavioral study of the effective channel mobility with temperature variation in the SiC MOSFET will be investigated. • Designing a gate driver which fits with the driving requirements of the SiC-MOSFET and provides a trade-off between the switching losses and the EMI behavior. • Designing a three-phase voltage source inverter with 16 kW rated power; the design includes minimizing the inverter losses and extracts the EMI model of the power inverter by considering the effects of the parasitic parameters; moreover a short guideline for selecting the heat-sink based on the static network is introduced. • Proposing a new and simplified carried-based PWM, this will reduce the harmonics in the output waveforms and enhance the utilization of the DC-link voltage. • Proposing a new strategy for compensating the dead-time effect in carrier based-PWM and to find out the proper dead-time level in VSI based on SiC –MOSFET. • Designing faults diagnosis and protection circuits in order to protect the power inverter from the common faults; overcurrent, short-circuit, overvoltage, and overtemperature faults.

APA, Harvard, Vancouver, ISO, and other styles

37

"Modeling and Control of a Three Phase Voltage Source Inverter with an LCL Filter." Master's thesis, 2015. http://hdl.handle.net/2286/R.I.29981.

Full text

Abstract:

abstract: This thesis addresses the design and control of three phase inverters. Such inverters are used to produce three-phase sinusoidal voltages and currents from a DC source. They are critical for injecting power from renewable energy sources into the grid. This is especially true since many of these sources of energy are DC sources (e.g. solar photovoltaic) or need to be stored in DC batteries because they are intermittent (e.g. wind and solar). Two classes of inverters are examined in this thesis. A control-centric design procedure is presented for each class. The first class of inverters is simple in that they consist of three decoupled subsystems. Such inverters are characterized by no mutual inductance between the three phases. As such, no multivariable coupling is present and decentralized single-input single-output (SISO) control theory suffices to generate acceptable control designs. For this class of inverters several families of controllers are addressed in order to examine command following as well as input disturbance and noise attenuation specifications. The goal here is to illuminate fundamental tradeoffs. Such tradeoffs include an improvement in the in-band command following and output disturbance attenuation versus a deterioration in out-of-band noise attenuation. A fundamental deficiency associated with such inverters is their large size. This can be remedied by designing a smaller core. This naturally leads to the second class of inverters considered in this work. These inverters are characterized by significant mutual inductances and multivariable coupling. As such, SISO control theory is generally not adequate and multiple-input multiple-output (MIMO) theory becomes essential for controlling these inverters. Dissertation/Thesis Masters Thesis Electrical Engineering 2015

APA, Harvard, Vancouver, ISO, and other styles

38

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

39

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 text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

40

Wu, Dong-Yue, and 吳東岳. "Design and Implementation of Two-Vector-Based Predictive Current Controllers for a Voltage Source Inverter with a Three Phase Passive Filter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/33122464866377213803.

Full text

Abstract:

碩士 國立臺灣海洋大學 電機工程學系 104 This thesis proposes a two-vector-based model-free predictive current control for a six-switch three-phase voltage source inverter with a three-phase passive filter. Generally, the existing predictive current control only consider the operations of eight switching modes, whereas the proposed method simulates the operations of fourteen ones, each of which is based on a combination of two voltage vectors. This implies that the accuracy of current prediction can be effectively improved by using the proposed strategy. In additional, the proposed method is based on the load current measurements and the current difference calculations together with the addition operation to predict the future load currents. Therefore, the proposed method does not depend on any system parameters, such as resistance, inductance, and back-EMF. Simulations are completed using MATLAB® software, whereas experiments are implemented via a 32-bit digital signal processor, TMS320F28335, made by Texas Instruments Company. Both simulation and experimental results show that the current-tracking performance of the proposed method is superior to that of the existing ones.

APA, Harvard, Vancouver, ISO, and other styles

41

Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3386.

Full text

Abstract:

The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks. In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies. Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.

APA, Harvard, Vancouver, ISO, and other styles

42

Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ernet.in/2005/3386.

Full text

Abstract:

The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks. In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies. Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.

APA, Harvard, Vancouver, ISO, and other styles

43

Gao, Yang. "A single phase static var compensator using a voltage source GTO inverter." 1993. http://hdl.handle.net/1993/29384.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Wang, Jung, and 王榮. "Design and Implementation of Six-Switch Inverter Fed Single-Phase Voltage Source." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/63c5k3.

Full text

Abstract:

碩士 國立交通大學 電控工程研究所 103 This thesis implements six-switch inverter fed single-phase voltage source. The purpose of this thesis is to maximize the switch utilization ratio under the limit of input voltage and rated values. In first, the linear and nonlinear loads under ideal source are studied. Then, the output inductor and capacitor of full-bridge inverter are designed. From the results, phase difference between both parts of the single-phase voltage source is helpful to maximize the switch utilization ratio. All the control algorithms are implemented in TI DSP chip. The provided results show that the proposed converter has acceptable performance and maximum switch utilization ratio.

APA, Harvard, Vancouver, ISO, and other styles

45

Eren, Suzan Zeynep. "Control of a Single-Phase Grid-Connected Voltage Source Inverter with LCL Filter." Thesis, 2013. http://hdl.handle.net/1974/8380.

Full text

Abstract:

This thesis presents new control approaches for improving the performance, stability, and efficiency of a single-phase grid-connected voltage source inverter (VSI) with an LCL filter that is used in renewable energy power conditioning applications. There are two main controllers that need to be designed: an external DC-bus voltage controller to balance the power flow coming into the VSI, and an internal current controller to control the current injected by the VSI into the utility grid. This thesis aims to find well-tailored control approaches for the aforementioned control loops. First, the stability and behavioral characteristics of the open-loop VSI with an LCL filter are explored using a Poincaré map, and the open-loop system is found to have marginal stability. A current control method is proposed, called composite nonlinear feedback (CNF), which offers significantly improved overall performance compared to the state-of-the-art proportional resonant (PR) controller with state feedback. To reduce the overall number of sensors in the system, two different observers are implemented to estimate the VSI state variables: (1) the Luenberger observer (LO), and (2) the sliding mode observer (SMO). To balance the system power flow, a new DC-bus voltage droop control method is proposed, that provides fast performance during transients. This control approach includes a novel discrete DC-bus voltage sensing technique, which effectively removes the double frequency ripple from the DC-bus voltage signal and prevents it from propagating into the current control loop. A variant on the DC-bus voltage droop control method, called adaptive droop control is proposed, which adaptively changes the droop gains in order to regulate the DC-bus voltage to a constant value. Finally, another variant on the DC-bus voltage droop control method is proposed, called optimized adaptive droop control, which adaptively changes the gains of the controller in order to minimize the overall system power losses. A stability analysis is conducted using the singular perturbation control theory, which allows a nonlinear dynamical system to be broken down into subsystems with different time scales. The results of the stability analysis confirm that the proposed closed-loop grid-connected VSI with an LCL filter is locally stable. Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-09-30 13:47:56.337

APA, Harvard, Vancouver, ISO, and other styles

46

Chen, Yao-Ting, and 陳要廷. "Three-Phase Grid-Connected Inverter with Power Control and Low-Voltage Ride Through." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49319098281739395508.

Full text

Abstract:

碩士 國立臺灣大學 電機工程學研究所 101 A three-phase grid-connected inverter, which is capable of controlling real/reactive power via internet and achieving low-voltage ride through (LVRT) function, is proposed in this thesis. By adopting the strategy of direct quadrature transformation to control the three-phase current injected into the utility line, active/reactive power control can be achieved successfully by using the three-phase three-wire voltage source inverter. An EIA-485 communication interface is also developed for users to give the active/reactive power commend via internet. Besides, in order to achieve the LVRT function, a new method is proposed to calculate the accurate grid voltage without using the conventional phase-locked loop (PLL) so that the three-phase inverter can remain connecting to the utility line during the most severe voltage drop scenario. The proposed strategy also allows the three-phase inverter to maintain grid-connected operation during the voltage recovery period. Finally, experimental results measured from a prototype circuit are presented to verify the performances of the proposed three-phase grid-connected inverter with real/reactive power and LVRT capability. Keywords：Communication through internet、Reactive power、LVRT(Low-Voltage Ride through)、Grid-connected、Three-phase inverter、EIA-485、Grid voltage calculation

APA, Harvard, Vancouver, ISO, and other styles

47

CHAN, HSIAO-YEN, and 詹曉炎. "Burn-in Test with Voltage-Controlled Regulator for Three-Phase Inverter Drives System." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/70899318902090602320.

Full text

Abstract:

碩士 南台科技大學 電機工程系 92 In order to increase three-phase induction motor drives stability, the traditional methods use R,RL or motor loads for the burn-in test about 24-48 hours, but test process to be bound to consumption energy, and use hot form loose, not only production costs increase,but also occupy equipment space. In order to save energy and reduce test costs, In this paper bring up use circulate electric current mode self-load bank burn-in test system employ inverter parallel connection technology. In this method, voltage-controlled regulator use parallel connect with system, Regulator controll that three-phase induction motor drives output power, change load characteristic . And power flow guide to the input terminal of tested unit, that's what main power energy circulate tested unit, main test electric current circuit without connect to utility grid directly, tested unit have more stability and safe. The operation frequency of tested united and unility can be different. Paper use capacity 1500W/220V three-phase induction motor drive as tested unit. According to experiment result , the saved energy in the burn-in test is approximately 80% of that lost by the conventional method,using a direct load.

APA, Harvard, Vancouver, ISO, and other styles

48

Xiu-HuaGuo and 郭修華. "Automatic Voltage Compensation Technique for Three-Phase Stand-Alone Inverter with Unbalanced / Nonlinear Load." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/88587974821323491727.

Full text

Abstract:

碩士 國立成功大學 電機工程學系 103 In this thesis, a three-phase inverter providing automatic voltage compensation for unbalanced or nonlinear load under stand-alone operation is presented. An ideal load-side inverter should provide constant amplitude, frequency, and sinusoidal voltage at point of common coupling (PCC). Without the stiff sinusoidal voltage support by grid, voltage quality at PCC is heavily affected by the type of loads. The nonlinear loads could produce voltage harmonics that degrade voltage quality. To maintain voltage quality at certain level, a proportional-resonant (PR) controller embedded with automatic harmonic compensation scheme is proposed. Harmonic components of voltage can be neutralized by resonant controllers that are tuned at harmonic frequencies. This method requires that the voltage harmonics need to be identified before resonant controllers are applied. Using the fast Fourier transform (FFT), dominant harmonic components could be identified for the PR controller to compensate harmonics at some resonant frequencies. The effectiveness of proposed voltage compensation strategy is verified through experiments on a testbed of the three-phase stand-alone system.

APA, Harvard, Vancouver, ISO, and other styles

49

Kuo, Wei-Ting, and 郭威廷. "Low Voltage Ride Through Capability Implementation of the Three-Phase Grid-Connected PV Inverter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/65556084594034654829.

Full text

Abstract:

碩士 國立臺灣大學 電機工程學研究所 101 When the grid experiences unbalanced voltages sag, the output power of the grid-connected inverter will have second harmonics. The objective of this thesis is to propose a new control scheme based on Lagrange multiplier method to calculate the current commands for the Photovoltaic (PV) inverter with the low-voltage ride-through (LVRT) capability. The current commands can control the second harmonics in the output power of the grid-connected inverter. The proposed method can combine with the maximum current amplitude control (MCAC) strategy. Computer simulations are shown to verify the performance of the proposed control scheme.

APA, Harvard, Vancouver, ISO, and other styles

50

Lin, Kuen-Shian, and 林坤賢. "Investigation of Different Modulation Methods for Three-Phase Z-Source Inverter and FPGA Realization." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/02679182034983502403.

Full text

Abstract:

碩士 國立高雄應用科技大學 電機工程系博碩士班 101 This thesis analyzes and discusses the modulation methods for three phase z-source inverter. The z-source inverter employs a unique impedance network and shoot-through state to boost the DC voltage and improve the drawback of traditional inverter. In this thesis, the modulation methods for sinusoidal pulse width modulation and space vector modulation are discussed, in both modulation techniques using three control methods,which are respectively simple boost control, maximum boost control, and maximum constant boost control, to achieve the boost effect. The simulation results of MATLAB/Simulink/SimPowerSystems are used to compare the boost effect and differences of each modulation method. The control module is made in Xilinx ISE software, and downloaded to FPGA developer board for verifing its feasibility.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Three phase voltage source inverter'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles