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1

Gokgoz, Sinan. "A Stand-alone Induction Powered Current And Current Harmonics Measurement System For Distribution Lines." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614967/index.pdf.

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The presence of information and communication technologies in the field of energy is increasing every day. Smart grid subject which aims to increase the percentage of energy generation through renewable resources and to make consumers to be involved in grid actively, is gaining importance day by day. In order to provide an effcient and reliable operation of smart grid network, it is necessary to collect relevant parameters from network components via communication infrastructure and to evaluate collected information. Also, with the inclusion of distributed energy sources in the power lines, collection of relevant data becomes important in order to ensure the quality of power. In the scope of this study, to measure current parameters, two DSP based electronic circuits and necessary embedded software have been developed. Data acquisition card is a fixed device which is to be installed to a point on the power line to gather current value samples. By means of being fed through magnetic induction from the line, this part of the system could stay on-line permanently and this allows taking measurements on demand. Sampling of line current is performed through principle of magnetic induction from the line on current sensing instrument which is connected to data-acquisition part. Also by utilization of clamp-on instruments, cutting of energy lines is not needed. Samples received by control card over radio frequency or infrared communication, are evaluated with the help of Discrete Fourier Transform (DFT). Control card can show information about Root mean square (RMS) value and harmonic components of line current and total harmonics distortion (THD) on graphic LCD. Present state of the system was tested in LV and MV environments and shown to be used on distribution lines. The system presented in this study is open to improvements and suggestions to make the system to be able to work on high voltage lines are made.
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2

Tedesco, Lawrence A. Jr. "A Unified Measure of Audio System Fidelity." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/598.

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A new technique to qualitatively measure distortion in dynamically controlled audio systems using non-stationary noise sequences is explored and compared to traditional methods based upon stationary test signals. This technique can easily be adapted to give a qualitative measure of distortion as a function of the perceived Sound Pressure Level (SPL).
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3

Duggan, E. "Measurement, analysis and mathematical modelling of harmonic distortion in power systems." Thesis, Staffordshire University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232907.

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4

Tella, Pranavi Chowdari Islam Naz E. "The study of single phase diode rectifiers with high power factor and low total harmonic distortion." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/5677.

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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 6, 2009). Thesis advisor: Dr. Naz E. Islam. Includes bibliographical references.
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5

Ferrar, Anthony Maurice. "Measurement and Uncertainty Analysis of Transonic Fan Response to Total Pressure Inlet Distortion." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51747.

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Distortion tolerant fans represent the enabling technology for the successful implementation of highly integrated airframe propulsion system vehicles. This investigation extends the study of fan-distortion interactions to an actual turbofan engine with a total pressure distortion profile representative of a boundary-layer ingesting (BLI) embedded engine. The goal was to make a series of flow measurements that contribute to the overall physical understanding of this complex flow situation. Proper uncertainty analysis is critical to extracting meaning from the data measured in this study. The important information in the measurements is contained in small differences that lead to large impacts on the fan performance. In some cases, these differences were measured to a useful degree of accuracy, while in others they were not. One important application of the uncertainty analysis techniques developed in this work is the identification of the dominant error sources that resulted in unacceptable uncertainties. This dissertation presents an experimental study of transonic fan response to inlet total pressure distortion. A Pratt and Whitney JT15D-1 turbofan engine was subjected to a total pressure distortion representative of a boundary layer ingesting serpentine inlet. A 5-hole probe measured the aerodynamic response of the fan rotor in terms of flow angles, total pressure, and static pressure. A thermocouple embedded in the probe measured the rotor outlet total temperature. These measurements enabled the full characterization of the flow condition at each measurement point. The results indicate that a trailing edge separation and reattachment cycle experienced by the blades caused variations in the work input to the flow and resulted in a non-uniform rotor outlet flow profile. The details of the aerodynamic process and several means for improving distortion response are presented in this context. As a second theme, the modern measurement and uncertainty analysis techniques required to obtain useful information in this situation are developed and explored. Uncertainty analysis is often treated as a less glamorous afterthought in experimental research. However, as technology develops along lines of ever increasing system-level integration, simply suggesting the solution to a single flow situation does not repre- sent closure to the larger problem. In addition to frameworks for developing distortion tolerant fans, frameworks for developing frameworks are required. Uncertainty-drivenexperimental techniques represent the enabling methodology for the discovery and un- derstanding of the subtle phenomena associated with such coupled performance. These considerations are required to extend the usefulness of the results to the overarching issue of integrating the complex performance of individual components into an overall superior system. The experimental methods and uncertainty analysis developed in this study are presented in this context.<br>Ph. D.
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6

Thunberg, Erik. "On the Benefit of Harmonic Measurements in Power Systems." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3219.

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7

Dey, Sourav. "Large-Signal Analysis of Buck and Interleaved Buck DC-AC Converters." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1409578634.

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8

Kirchmann, Carl Christian. "Automatic acoustic tests of conference phones." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326253.

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This master thesis was completed at Limes Audio in Umeå. Limes Audio are specialized in speech enhancement software which is mostly used in conference phones. Their software is used to reduce noise, echo cancellation as well as reduction of distortion. When a conference phone is malfunctioning it can be troublesome to find the cause of the problem. Common issues that lead to perceived poor audio quality are rattling plastics, loose parts and an environment with demanding acoustics. There is a need for automatic tests to run on conference phone which can diagnose audio quality and the acoustics of the environment where the conference phone is located in. A previous master thesis by Wilhelmsson called "Estimating Loudspeaker Distortion and Room Reverberation Time Using a Speakerphone" focused on evaluating several tests run in MATLAB for analyzing acoustic characteristics of a room. The goal of this thesis was to continue the work of the master thesis by Wilhelmsson. Previous tests served as a basis for this thesis. The tests where modified and rewritten in C and run on a Linux computer connected to a specific conference phone model. In the extended test made in this thesis using sine sweep signals, the reverberation time as well as the distortion for the conference phone setup was determined. The calculated reverberation time was compared to the results using Room EQ Wizard and gave almost identical results. Total harmonic distortion was not easy to relate to the perceived audio quality. There is a need to further develop methods to take into account other types of distortion than the total harmonic distortion. Rub &amp; buzz is one kind of distortion that could be of interest. To investigate pass or fail thresholds for reverberation time as well as distortion is central for further development of this test software.
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9

Grossman, Hy. "A NEXT GENERATION AIRCRAFT POWER MONITORING SYSTEM." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604535.

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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada<br>Historically, aircraft power monitoring has required the use of multiple signal conditioning functions to measure various parameters including voltage, current, frequency and phase. This information was then post processed to determine the characteristics of the 3-phase power quality on the aircraft. Recent developments in embedded DSP processors within signalconditioning systems provide the instrumentation engineer with expanded capabilities for realtime on-board power quality monitoring. Advantages include reduced space and bandwidth requirements and minimal wiring intrusion. For each phase, output data may include peak positive and negative voltages and currents, peak-to-peak, average and RMS voltages and currents, phase power (real and apparent), phase power factor, phase period (frequency), phase shift measurement from phase 1 (the reference phase) to phase 2, and from phase 1 to phase 3. In addition, a Fast Fourier Transform (FFT) is performed on each phase voltage to provide Total Harmonic Distortion measurements. This paper describes the methods employed in the implementation of these functions on a single signal-conditioning card in order to provide detailed information about the power quality of a three-phase aircraft power source.
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10

Al, Abed Isrà. "Measurement System at Large Bandwidth for Quality Evaluation of Electric Energy up to 150 kHz." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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Nowadays, Power Quality monitoring is an essential service many utilities perform for their industrial and other key commercial customers. Monitoring power quality has become specifically more effective in recent years due to the advent of the technology and software. Not only can a monitoring system provide information such as quality of the power and the causes of power system disturbances, but it is also able to identify problem conditions throughout the system prior they cause widespread customer complaints, equipment malfunctions, and even equipment failures. Power Quality problems are not necessarily limited to the utility power system. Many surveys have shown that most problems are localized within customer facilities. Essential requirements for a successful monitoring system include extensive data processing capabilities, easily understood reporting, and universal sharing of information.
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11

Häger, Emil. "Performance Evaluation of Medium-Power Voltage Inverters." Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-118568.

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Power inverters, used to convert DC power to AC, are often used in e.g. solar power applications. However, they tend to be impractically large and expensive; as such, power miniaturization is an active research area. In this thesis, several classes of modern power inverters are evaluated and compared with regards to size, efficiency and output quality in order to identify areas of potential improvement. Methods for estimation of THD, power losses and input ripple are created and verified against a simulation of a five-level neutral-point-clamped inverter with SPWM control. Finally, this design is implemented physically and is found to achieve 94.5% efficiency and 7% THD under low voltage laboratory conditions, while remaining smaller than an average textbook.
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12

Souza, Wesley Angelino de [UNESP]. "Desenvolvimento de sistema de aquisição e processamento para aplicações em qualidade de energia." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87201.

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Made available in DSpace on 2014-06-11T19:22:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-19Bitstream added on 2014-06-13T20:49:15Z : No. of bitstreams: 1 souza_wa_me_bauru.pdf: 3309362 bytes, checksum: a37e3a04f60e9ebbd2f490264d198dbf (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Este trabalho teve como o desenvolvimento de um sistema de aquisição e processamento de dados para aplicações em Qualidade de Energia Elétrica (QEE). Do ponto de vista dos circuitos de hardware desenvolvidos, buscou-se utilizar componentes de precisão elevada para o sensoriamento e condicionamento dos sinais de tensão e corrente. Além disso, foi implementado um algoritmo de auto calibração das medidas, em função da temperatura no medidor implementado. O processamento dos dados foi realizado através de um processador digital de sinais (DSP, Digital Sinal Processor) de 32 bits, com aritmética de ponto flutuante. Também foi agregado ao sistema um módulo de comunicação sem fio, de forma que os dados medidos pudessem ser enviados a outros dispositivos para armazenamento ou análise remota. Do ponto de vista da aplicação em Qualidade de Energia, foram implementados diversos algoritmos de indicadores de QEE, tais como o de Distorção Harmônica Total (DHT), para a validação preliminar do sistema desenvolvido. Entretanto, do ponto de vista dos estudos e pesquisas realizadas pelo Grupo de Automação e Sistemas Integráveis (GAS/UNESP), no que diz respeito à análise de circuitos elétricos sob condições de formas de onda não sensoriais e/ou desequilibradas, o sistema desenvolvido foi também utilizado para avaliar o comportamento e desempenho da Teoria de Potência Conservativa, proposta recentemente por Tenti et al. e de novos fatores de conformidade (ou desempenho) para a avaliação da QEE em sistemas polifásicos com cargas não lineares. Diversos resultados de simulação e experimentais foram apresentados e constrastados a fim de validar os algoritmos utilizados no DSP utilizado, bem como para permitir a avaliação da Teoria de Potência Conservativa para interpretação de diferentes circuitos e condições de operações<br>This study aimed to develop a data acquisition and processing system for Power Quality applications. From the hardware point of view, high precision components have been used for the vallage and current sensing and signal conditioning. In addition, a self-calivration algorithm has been implemented in order to adjust the measured values in terms of the estimated temperature. The data processing was performed by means of 32-bit floating point digital signal processor (DSP). A wirelless communication module has also been added, so that the measured data could be sent to other storage devices or remote analyzers. From the perspective of power quality applications, several algorithms have implemented, such as the Total Harmonic Distortion (THD) for the preliminary validation of the developed system. However, considering the studies and surveys carried out by the studies and survey carried out by the Group of Automation and Integrated Systems (GASI/UNESP), especially those related to the analysis of electrical circuits under non-sinusoidal and/or unbalanced waveform conditions, the implemented system has been applied to the evaluation of the Conservative Power Theory (CPT), recently proposed by Tenti et al. Several simulation and experimental results have been depicted and compared in order to validate the practical DSP implementation of the required algorithms, as well as, for the purpose of analyzing different circuit's interpretation by means of the CPT
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13

Joca, Davi Rabelo. "TÃcnica de ModulaÃÃo para ReduÃÃo de DHT em Inversor MultinÃvel com Capacitor Flutuante de TrÃs NÃveis." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11222.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior<br>Diante da necessidade em aperfeiÃoar as tecnologias existentes para a conversÃo de energia elÃtrica em sistemas de alta potÃncia, este trabalho tem por finalidade projetar, analisar e implementar experimentalmente uma tÃcnica de modulaÃÃo com o intuito de reduzir o conteÃdo harmÃnico da tensÃo de saÃda em um inversor multinÃvel com capacitor flutuante de trÃs nÃveis. Algumas das diversas tÃcnicas de modulaÃÃo (PSPWM, LSPWM, HE-PWM e CSV-PWM) foram analisadas e implementadas no controlador digital FPGA a fim de comparar suas caracterÃsticas de desempenho com a tÃcnica de modulaÃÃo proposta. AlÃm disso, foi realizado o estudo de perdas da topologia de inversor multinÃvel com capacitor flutuante de trÃs nÃveis e a anÃlise teÃrica da distorÃÃo harmÃnica total da modulaÃÃo proposta. Finalmente, o desenvolvimento digital das tÃcnicas mostrou resultados coerentes, com formas de onda obtidas experimentalmente com alta qualidade de resoluÃÃo. A comparaÃÃo entre as estratÃgias de modulaÃÃo em termos de DHT resultou positivamente à modulaÃÃo proposta, cujos resultados experimentais de DHT nas tensÃes de linha na saÃda apresentaram o melhor desempenho para toda a faixa de Ãndices de modulaÃÃo comparadas Ãs tÃcnicas PSPWM, LSPWM-POD e CSV-PWM e uma reduÃÃo de atà 4,5% em relaÃÃo à HE-PWM. Isto comprova o estudo teÃrico realizado e sua aplicaÃÃo no inversor multinÃvel com capacitor flutuante de trÃs nÃveis.<br>Given the need to improve the existing technologies for electrical energy conversion into high power systems, this works purpose to design, analyze and implement a modulation technique that aims to reduce the output voltage harmonic content on the three-level flying capacitor multilevel inverter. Some of the various conventional modulation techniques (PSPWM, LSPWM, HE-PWM e CSV-PWM) have been analyzed and implemented in FPGA controller in order to compare their performance features with the proposed modulation technique. Furthermore, the losses study of the three-level flying capacitor multilevel inverter topology and the total harmonic distortion theoretical analysis of the proposed modulation technique have been made. Finally, the digital implementation of the techniques showed consistent results with experimentally obtained waveforms with high quality resolution. The comparison between the modulation strategies in the THD rates resulted positively for the proposed modulation, which THD experimental results in the line output voltage showed the best performance for all range of modulation indexes compared to techniques PSPWM, LSPWM-POD and CSV-PWM and the reduction of up to 4.5% better than HE-PWM. This proved the theoretical study done and its application in three-level flying capacitor multilevel inverter.
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14

Souza, Wesley Angelino de. "Desenvolvimento de sistema de aquisição e processamento para aplicações em qualidade de energia /." Bauru : [s.n.], 2011. http://hdl.handle.net/11449/87201.

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Resumo: Este trabalho teve como o desenvolvimento de um sistema de aquisição e processamento de dados para aplicações em Qualidade de Energia Elétrica (QEE). Do ponto de vista dos circuitos de hardware desenvolvidos, buscou-se utilizar componentes de precisão elevada para o sensoriamento e condicionamento dos sinais de tensão e corrente. Além disso, foi implementado um algoritmo de auto calibração das medidas, em função da temperatura no medidor implementado. O processamento dos dados foi realizado através de um processador digital de sinais (DSP, Digital Sinal Processor) de 32 bits, com aritmética de ponto flutuante. Também foi agregado ao sistema um módulo de comunicação sem fio, de forma que os dados medidos pudessem ser enviados a outros dispositivos para armazenamento ou análise remota. Do ponto de vista da aplicação em Qualidade de Energia, foram implementados diversos algoritmos de indicadores de QEE, tais como o de Distorção Harmônica Total (DHT), para a validação preliminar do sistema desenvolvido. Entretanto, do ponto de vista dos estudos e pesquisas realizadas pelo Grupo de Automação e Sistemas Integráveis (GAS/UNESP), no que diz respeito à análise de circuitos elétricos sob condições de formas de onda não sensoriais e/ou desequilibradas, o sistema desenvolvido foi também utilizado para avaliar o comportamento e desempenho da Teoria de Potência Conservativa, proposta recentemente por Tenti et al. e de novos fatores de conformidade (ou desempenho) para a avaliação da QEE em sistemas polifásicos com cargas não lineares. Diversos resultados de simulação e experimentais foram apresentados e constrastados a fim de validar os algoritmos utilizados no DSP utilizado, bem como para permitir a avaliação da Teoria de Potência Conservativa para interpretação de diferentes circuitos e condições de operações<br>Abstract: This study aimed to develop a data acquisition and processing system for Power Quality applications. From the hardware point of view, high precision components have been used for the vallage and current sensing and signal conditioning. In addition, a self-calivration algorithm has been implemented in order to adjust the measured values in terms of the estimated temperature. The data processing was performed by means of 32-bit floating point digital signal processor (DSP). A wirelless communication module has also been added, so that the measured data could be sent to other storage devices or remote analyzers. From the perspective of power quality applications, several algorithms have implemented, such as the Total Harmonic Distortion (THD) for the preliminary validation of the developed system. However, considering the studies and surveys carried out by the studies and survey carried out by the Group of Automation and Integrated Systems (GASI/UNESP), especially those related to the analysis of electrical circuits under non-sinusoidal and/or unbalanced waveform conditions, the implemented system has been applied to the evaluation of the Conservative Power Theory (CPT), recently proposed by Tenti et al. Several simulation and experimental results have been depicted and compared in order to validate the practical DSP implementation of the required algorithms, as well as, for the purpose of analyzing different circuit's interpretation by means of the CPT<br>Orientador: Fernando Pinhabel Marafão<br>Coorientador: Ivando Severino Diniz<br>Banca: Lourenço Matakas Junior<br>Banca: Marcelo Nicoletti Franchin<br>Mestre
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15

Earick, Weston R. "DESIGN OF A HIGH-POWER, HIGH-EFFICIENCY, LOW-DISTORTION DIRECT FROM DIGITAL AMPLIFIER." Wright State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=wright1155008919.

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16

Pignatti, Alex Almeida. "O impacto da topologia de conexão de transdutores na obtenção de indicadores de qualidade de energia." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-15072013-154428/.

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A Agência Nacional de Energia Elétrica (ANEEL) deverá estabelecer a regulamentação para distúrbios de qualidade de energia em um futuro próximo. Há ainda questões em aberto sobre os procedimentos de medição e limites máximos para os indicadores de qualidade de energia. Este trabalho aborda uma dessas questões, que é a conexão de transdutores e os impactos nos índices de qualidade de energia associados. Simulações em ATPDraw e campanhas de medição foram realizadas de modo a identificar o comportamento dos indicadores de distorção harmónica sob as duas configurações possíveis de conexão de transdutores: dois equipamentos com ligação entre fases ou três com ligação fase-neutro. Os resultados das simulações e os valores medidos mostram grandes discrepâncias entre ambas as configurações, e as diferenças tornam-se ainda mais significativas com o incremento do desequilíbrio do sistema elétrico. As causas subjacentes deste fenômeno são investigadas e discutidas<br>The Brazilian electricity regulatory agency (ANEEL) is expected to establish a legal framework for quality disturbances in the near future. There are still some open questions regarding metering procedures and maximum limits for Power Quality indicators. This work addresses one of such issues, namely the connection of the associated transducers and its impact on PQ indexes. Simulations in ATPDraw and on-field measurement campaigns were carried out so as to identify the behavior of harmonic distortion indicators under the two possible transducer configurations: two phase-to-phase or three phase-to-neutral transducers. Simulation results and measured values show large discrepancies between both configurations, and the differences become more significant as the electrical systems unbalance increases. The underlying causes of this phenomenon are investigated and discussed.
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Bernáth, František. "SW nadstavba analyzátoru sítí pro automatický návrh nn kompenzační jednotky na základě měření." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218704.

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Thesis is devoted to a problem of Power Factor Correction on the low voltage level. It has still its own difficulties despite the fact that topic moved through long development. The main goal of this work is to offer reader variable procedure considering design process. It is based on use of measured data of network analyzer Meg30. The design algorithm has to share a maximum of eventual influencing factors. Therefore the body of master thesis goes through detailed analysis of Power Factor Correction.
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Vývoda, Marek. "Kompenzace účiníku a posouzení zpětných vlivů indučního ohřevu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219077.

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This Diploma thesis deals with design of for power factor correction device for mid-frequency-range induction heating and also with assessment of correction device influence in harmonically distorted environment from the distribution net point of view. Research chapters contain of main characteristics of electrical power quality and theoretical background of reactive power, which is in our case caused by driven non-linear elements. Further, the heating power supply block is explained and simulations of power consumption in Matlab - Simulink is done, within the prove of corrective tools design. After the build of corrective tool assemblies, measurements are matched with the simulation results.
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Pelicer, Junior João Carlos. "Emprego de topologia boost semicontrolada para mitigação do conteúdo harmônico de corrente em conversores de 12 pulsos /." Ilha Solteira, 2019. http://hdl.handle.net/11449/180812.

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Orientador: Falcondes José Mendes de Seixas<br>Resumo: Os conversores multipulsos têm sido muito utilizados para a melhoria da qualidade de energia elétrica em sistemas de retificação trifásicos. O principal motivo para tal afirmação é a robustez apresentada por esses conversores, aliada às características intrínsecas da estrutura, que resulta no cancelamento natural de certas componentes de corrente na rede, devido ao defasamento angular provocado pela ação do transformador ou autotransformador utilizado. O que se propõe nesse trabalho é a substituição de cada ponte retificadora a diodos, presente no conversor de 12 pulsos, por uma topologia retificadora trifásica semicontrolada, baseada no conversor boost operando no modo de condução descontínuo (MCD), de modo que, seja possível reduzir de maneira significativa a DHTi (Distorção Harmônica Total de corrente), bem como, incorporar os volumosos transformadores de interfase (IPTs) aos indutores boost de alta frequência, resultando na redução de peso e volume. Foram confeccionadas duas versões do conversor de 12 pulsos com retificadores semicontrolados, uma utilizando transformador isolador e a outra um autotransformador. O que se verificou para ambas as configurações é que a estrutura apresenta um reduzido conteúdo harmônico de corrente se comparado ao conversor tradicional e que, ao se operar no modo de condução descontínuo, faz-se possível o emprego de uma lógica de controle simples, possibilitando assim empregar somente uma malha de tensão, e reduzir significativamente a DHTi do... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Multipulse converters have been widely employed for electrical power quality improvement in three-phase rectifiers systems. The main reason for this statement is the robustness shown by these structures, allied to their natural characteristics, resulting in harmonic canceling at the mains, due to the phase displacement provided by the transformer/autotransformer. In this work, it is proposed the replacement of each rectifier bridge, present in the 12-pulse converter, by a three-phase half-controlled rectifier topology, based on DCM (Discontinuous Conduction Mode) boost converter, thus making it possible to significative reduce the THDi (Total Harmonic Distortion) of the current injected on the mains by the structure. It also incorporates the voluminous IPT's (Interphase Transformer) in the boost high-frequency inductor, resulting in a reduction of weight and size. Two versions of the 12-pulse converter with semicontrolled rectifiers were made, one using an isolating transformer and other using an autotransformer. It was verified that both configurations present a reduced THDi when compared to the traditional converter. So, by electing DCM, it is possible to employ a simpler control logic, employing only one voltage loop and significantly reducing the THDi.<br>Doutor
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Al, Shammeri Bashar Mohammed Flayyih. "A novel induction heating system using multilevel neutral point clamped inverter." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/8305.

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This thesis investigates a novel DC/AC resonant inverter of Induction Heating (IH) system presenting a Multilevel Neutral Point Clamped (MNPCI) topology, as a new part of power supply design. The main function of the prototype is to provide a maximum and steady state power transfer from converter to the resonant load tank, by achieving zero current switching (ZCS) with selecting the best design of load tank topology, and utilizing the advantage aspects of both the Voltage Fed Inverter (VFI) and Current Fed Inverter (CFI) kinds, therefore it can considered as a hybrid-inverter (HVCFI) category . The new design benefits from series resonant inverter design through using two bulk voltage source capacitors to feed a constant voltage delivery to the MNPCI inverter with half the DC rail voltage to decrease the switching losses and mitigate the over voltage surge occurred in inverter switches during operation which may cause damage when dealing with high power systems. Besides, the design profits from the resonant load topology of parallel resonant inverter, through using the LLC resonant load tank. The design gives the advantage of having an output current gain value of about Quality Factor (Q) times the inverter current and absorbs the parasitic components. On the contrary, decreasing inverter current means decreasing the switching frequency and thus, decreasing the switching losses of the system. This aspect increases the output power, which increases the heating efficiency. In order for the proposed system to be more reliable and matches the characteristics of IH process , the prototype is modelled with a variable LLC topology instead of fixed load parameters with achieving soft switching mode of ZCS and zero voltage switching (ZVS) at all load conditions and a tiny phase shift angle between output current and voltage, which might be neglected. To achieve the goal of reducing harmonic distortion, a new harmonic control modulation is introduced, by controlling the ON switching time to obtain minimum Total Harmonic Distortion (THD) content accompanied with optimum power for heating energy.
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21

Tan, Benjamin H. "A Novel Arc Welding Power Supply with Improved Power Factor Correction." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2199.

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This paper presents the design and development of a novel Arc Welding Power Supply utilizing a modified two-switch forward converter topology. The proposed design improves the power quality by improving power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. Hardware implementation of the proposed design was built on a scaled-down prototype for a proof-of-concept of the new topology. The prototype specifications were created for a 5A, 20V output with a 20-24V, 60Hz input. This project demonstrated that the proposed new topology was successful in obtaining a near unity power factor and a total harmonic distortion of less than 2%. Additionally, the prototype followed the simulation and calculations of a boost-buck function while varying duty cycle, and the final measurements aligned well with waveforms from the simulation.
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Fernández, Palomeque Efrén Esteban. "Optimization of a CSI inverter and DC/DC elevator with silicon carbide devices, for applications in electric traction systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/666485.

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The applications of electric traction systems currently focus on developing technologies with greater energy efficiency and lower environmental impact. Manufacturers of hybrid and electric vehicles are looking for ways to improve and optimize the efficiency of their models. Manufacturers are looking for more efficient and more compact converter topologies. The use of new band gap materials in the construction of these topologies has generated many debates and new lines of research especially in the optimization of these topologies. The silicon carbide (SiC) based switching devices provide significant performance improvements in many aspects, including lower power dissipation, higher operating temperatures, and faster switching, compared with conventional Si devices, all these features make that these devices generate interest in applications for electric traction systems. This work presents a method for improving total harmonic distortion (THD) in the currents of output and efficiency in SiC current source inverter for future application in an electric traction system. The method proposed consists in improving the coupling of a bidirectional converter topology V-I and CSI. The V-I converter serves as a current regulator for the CSI and allows the recovery of energy. The method involves an effective selection of the switching frequencies and phase angles for the carriers signals present in each converter topology. With this method, it is expected to have a reduction of the total harmonic distortion THD in the output currents. In addition, an analysis of the losses in the motor and topologies of power converters is developed considering the optimization method previously analyzed. The weighted average efficiency of the whole system (power converters + motor) in differents conditions of operations is presented.<br>Las aplicaciones de los sistemas de tracción eléctrica actualmente se centran en el desarrollo de tecnologías con mayor eficiencia energética y menor impacto ambiental. Los fabricantes de vehículos híbridos y eléctricos están buscando formas de mejorar y optimizar la eficiencia de sus modelos. Los fabricantes buscan topologías de convertidores más eficientes y más compactas. El uso de nuevos materiales de banda prohibida en la construcción de estas topologías ha generado muchos debates y nuevas líneas de investigación, especialmente en la optimización energética de las mismas. Los dispositivos de conmutación basados en carburo de silicio (SiC) proporcionan mejoras significativas en la eficiencia en muchos aspectos, incluida una menor disipación de potencia, temperaturas de funcionamiento más altas y una conmutación más rápida, en comparación con los dispositivos de Si convencionales. Todas estas características hacen que estos dispositivos generen interés en las aplicaciones de sistemas tracción eléctrica. Este trabajo presenta un método para mejorar la distorsión armónica total (THD) en las corrientes de salida y eficiencia en el inversor de fuente de corriente SiC para aplicaciones futuras en un sistema de tracción eléctrica. El método propuesto consiste en mejorar el acoplamiento de una topología de convertidor bidireccional V-I y CSI. El convertidor V-I sirve como un regulador de corriente para el CSI y permite la recuperación de energía. El método implica una selección efectiva de las frecuencias de conmutación y los ángulos de fase para las señales portadoras presentes en cada topología del convertidor. Con este método, se espera una reducción de la distorsión armónica total THD en las corrientes de salida. Además, se desarrolla un análisis de las pérdidas en el motor y las topologías de los convertidores de potencia considerando el método de optimización analizado previamente. Se presenta la eficiencia promedio ponderada de todo el sistema (convertidores de potencia + motor) en diferentes condiciones de operación
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SILVA, Elson Natanael Moreira. "ESTIMAÇÃO PROBABILÍSTICA DO NÍVEL DE DISTORÇÃO HARMÔNICA TOTAL DE TENSÃO EM REDES DE DISTRIBUIÇÃO SECUNDÁRIAS COM GERAÇÃO DISTRIBUÍDA FOTOVOLTAICA." Universidade Federal do Maranhão, 2017. http://tedebc.ufma.br:8080/jspui/handle/tede/1296.

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Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-04-17T13:14:17Z No. of bitstreams: 1 Elson Moreira.pdf: 7883984 bytes, checksum: cf59b3b0b24a249a7fd9e2390b7f16de (MD5)<br>Made available in DSpace on 2017-04-17T13:14:17Z (GMT). No. of bitstreams: 1 Elson Moreira.pdf: 7883984 bytes, checksum: cf59b3b0b24a249a7fd9e2390b7f16de (MD5) Previous issue date: 2017-02-10<br>CNPQ<br>A problem of electric power quality that always affects the consumers of the distribution network are the harmonic distortions. Harmonic distortions arise from the presence of socalled harmonic sources, which are nonlinear equipment, i.e., equipment in which the voltage waveform differs from the current. Such equipment injects harmonic currents in the network generating distortions in the voltage waveform. Nowadays, the number of these equipment in the electrical network has increased considerably. However, the increasing use of such equipment over the network makes systems more vulnerable and prone to quality problems in the supply of electricity to consumers. In addition, it is important to note that in the current scenario, the generation of electricity from renewable sources, connected in the secondary distribution network, is increasing rapidly. This is mainly due to shortage and high costs of fossil fuels. In this context, the Photovoltaic Distributed Generation (PVDG), that uses the sun as a primary source for electric energy generation, is the main technology of renewable generation installed in distribution network. However, the PVDG is a potential source of harmonics, because the interface of the PVDG with the CA network is carried out by a CC/CA inverter, that is a highly nonlinear equipment. Thus, the electrical power quality problems associated with harmonic distortion in distribution networks tend to increase and be very frequent. One of the main indicators of harmonic distortion is the total harmonic distortion of voltage ( ) used by distribution utilities to limit the levels of harmonic distortion present in the electrical network. In the literature there are several deterministic techniques to estimate . These techniques have the disadvantage of not considering the uncertainties present in the electric network, such as: change in the network configuration, load variation, intermittence of the power injected by renewable distributed generation. Therefore, in order to provide a more accurate assessment of the harmonic distortions, this dissertation has as main objective to develop a probabilistic methodology to estimate the level of in secondary distribution networks considering the uncertainties present in the network and PVDG connected along the network. The methodology proposed in this dissertation is based on the combination of the following techniques: three-phase harmonic power flow in phase coordinate via method sum of admittance, point estimate method and series expansion of Gram-Charlier. The validation of the methodology was performed using the Monte Carlo Simulation. The methodology was tested in European secondary distribution network with 906 nodes of 416 V. The results were obtained by performing two case studies: without the presence of PVDG and with the PVDG connection. For the case studies, the following statistics for nodal were estimated: mean value, standard deviation and the 95% percentile. The results showed that the probabilistic estimation of is more complete, since it shows the variation of due to the uncertainties associated with harmonic sources and electric network. In addition, they show that the connection of PV-DG in the electric network significantly affects the levels of of the electric network.<br>Um problema de qualidade de energia elétrica que afeta os consumidores da rede de distribuição secundária são as distorções harmônicas. As distorções harmônicas são provenientes da presença das chamadas fontes de harmônicas que são equipamentos de características não-lineares, ou seja, equipamentos em que a forma de onda da tensão difere da de corrente. Tais equipamentos injetam correntes harmônicas na rede produzindo, portanto distorções na forma de onda da tensão. Nos dias atuais, a quantidade desses equipamentos na rede elétrica tem aumentado consideravelmente. Porém, o uso crescente desse tipo de equipamento ao longo da rede torna os sistemas mais vulneráveis e propensos a apresentarem problemas de qualidade no fornecimento de energia elétrica aos consumidores. Além disso, é importante destacar que no cenário atual, a geração de energia elétrica a partir de fontes renováveis, conectada na rede de distribuição secundária, está aumentando rapidamente. Isso se deve principalmente devido a escassez e altos custos dos combustíveis fosseis. Neste contexto, a Geração Distribuída Fotovoltaica (GDFV), que utiliza o sol como fonte primária para geração de energia elétrica, é a principal tecnologia de geração renovável instalada na rede de distribuição no Brasil. Contudo, a GDFV é uma potencial fonte de harmônica, pois a interface da GDFV com a rede CA é realizada por um inversor CC/CA, que é um equipamento altamente não-linear. Desde modo, os problemas de qualidade de energia elétrica associados à distorção harmônica nas redes de distribuição tendem a aumentar e a serem bem frequentes nos consumidores da rede de distribuição secundárias. Um dos principais indicadores de distorção harmônica é a distorção harmônica total de tensão ( do inglês “Total Harmonic Distortion of Voltage”) utilizada pelas concessionárias de energia elétrica para quantificar os níveis de distorção harmônica presentes na rede elétrica. Na literatura técnica existem várias técnicas determinísticas para estimar a . Essas técnicas possuem a desvantagem de não considerar as incertezas presentes na rede elétrica, tais como: mudança na configuração da rede, variação de carga e intermitência da potência injetada pela geração distribuída renovável. Portanto, a fim de fornecer uma avaliação mais precisa das distorções harmônicas, este trabalho tem como principal objetivo desenvolver uma metodologia probabilística para estimar o nível de em redes de distribuição secundária considerando as incertezas presentes na rede e na GDFV conectada ao longo da rede. A metodologia proposta nesta dissertação se baseia na combinação das seguintes técnicas: fluxo de potência harmônico trifásico em coordenadas de fase via método de soma de admitância, método de estimação por pontos e expansão em série de Gram-Charlier. Além disso, a validação da metodologia foi realizada utilizando a Simulação Monte Carlo. A metodologia desenvolvida foi testada na rede de distribuição secundária europeia com 906 nós de 416 V. Os resultados foram obtidos realizando dois casos de estudos: sem a presença de GDFV e com a conexão de GDFV. Para ambos os casos de estudo as seguintes estatísticas do nodal foram estimadas: valor médio, desvio padrão e o percentil de 95%. Os resultados demonstraram que a estimação probabilística da é mais completa, pois mostra a variação da devido às incertezas associadas com as fontes de harmônicas e as da rede elétrica. Os resultados também mostram que a conexão da GDFV afeta significativamente os níveis de da rede elétrica
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24

Dušek, Samuel. "Techniky slučování kanálů za účelem zvýšení dynamického rozsahu kanálu s rozsahem ±10 V." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413045.

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Cílem této diplomové práce je změřit a vyhodnotit parametry techniky slučování kanálů, která je momentálně implementována v součástce AD7606C firmy Analog Devices. Poté, na základě výsledků z měření, navrhnout a odsimulovat několik možností, pomocí kterých by tato technika mohla dosahovat vyšších hodnot dynamického rozsahu a celkového harmonického zkreslení. V průběhů práce bylo zjištěno, že pomocí zvýšení zesílení kanálu s nižším rozsahem společně se snížením mezní frekvence celého signálového řetězce může tato technika dosahovat až 118.6 dB dynamického rozsahu, což je o 3.6 dB více, než bylo změřeno na AD7606C. Dále také bylo zjištěno, že pomocí jednoduchého algoritmu implementovaného v logickém bloku, je možné dosáhnout imunity vůči hodnotě externího rezistoru, který zákazníci používají jako součást anti-aliasingového filtru.
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25

Oliveira, Francisco Hércules de. "Estudo de técnica utilizando a modulação PWM baseada em portadora aplicada ao inversores monofásicos assimétricos com diodos de grampeamento." Universidade Federal da Paraíba, 2017. http://tede.biblioteca.ufpb.br:8080/handle/tede/9783.

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Submitted by Gilvanedja Silva (gilvanedja@biblioteca.ufpb.br) on 2018-03-22T20:42:08Z No. of bitstreams: 1 arquivototal.pdf: 11929036 bytes, checksum: e796f3e04cbf0cf6da3fa9648d4f9270 (MD5)<br>Made available in DSpace on 2018-03-22T20:42:09Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 11929036 bytes, checksum: e796f3e04cbf0cf6da3fa9648d4f9270 (MD5) Previous issue date: 2017-05-25<br>This work presents a technique using carrier-based pulse width modulation (PWM) applied to single-phase asymmetrical multilevel inverters with diodes clamped, aiming to increase the amount of output voltage levels to improve signal quality, reducing the total harmonic distortion rate (THD). The technique was used in inverters of three, four and five levels per arm, providing an output signal with seven, thirteen and nineteen levels respectively, presenting two, six and ten levels higher than the equivalent symmetrical multilevel inverters. The technique was described with a set of equations and procedures that can be generalized for inverters of any number of levels. To verify the operation, simulations were performed using the PSIM program and an experimental assembly of an asymmetrical multilevel inverter of three levels was performed, using a field programmable gate array device (FPGA) in the implementation of the PWM modulator. Finally, the simulation and experimental results that prove the effectiveness of the modulation strategy employed in this work are presented and compared<br>Este trabalho apresenta uma técnica utilizando a modulação por largura de pulso (PWM) baseada em portadora, aplicada aos inversores multiníveis monofásicos assimétricos com diodos de grampeamento, com o objetivo de elevar a quantidade de níveis na tensão de saída, para melhorar a qualidade do sinal, reduzindo a taxa de distorção harmônica total (THD). A técnica foi empregada em inversores de três, quatro e cinco níveis por braço, fornecendo um sinal de saída com sete, treze e dezenove níveis respectivamente, apresentando dois, seis e dez níveis a mais que os inversores multiníveis simétricos equivalentes. A técnica foi descrita com um conjunto de equações e procedimentos que pode ser generalizada para inversores de qualquer número de níveis. Para comprovar o funcionamento, foram realizadas simulações utilizando o programa PSIM e efetuada montagem experimental de uma inversor multinível assimétrico de três níveis, utilizando na implementação do modulador PWM um dispositivo em matriz de porta programável em campo (FPGA). Por fim, são apresentados e comparados os resultados de simulações e experimentais que comprovam a eficácia da estratégia de modulação empregada neste trabalho
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26

Moussa, Hassan. "Contribution to the Decentralized Energy Management of Autonomous AC-Microgrid." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0161/document.

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Cette thèse porte sur des micro-réseaux AC isolées qui permettent l’intégration des ressources énergétiques distribuées (DER) pouvant fournir leur énergie d'alimentation existante de manière contrôlée pour assurer le bon fonctionnement global du système. L'interconnexion d'un DER à une micro-réseau s'effectue habituellement en utilisant un convertisseur d'interface distribué (DIC) (i.e. un bloc d'interface d'électronique de puissance générale) qui est constitué d’un module de convertisseur à l'entrée de la source, un onduleur de tension (VSI), un module d'interfaçage de sortie, et le module de commande. Dans cette thèse on réalise plusieurs lois de commande basées sur des méthodes décentralisées. L'accent principal est mis sur les fonctions "Droop" qui ont la tâche de maintenir un équilibre de distribution d'énergie entre les différentes sources énergétiques connectées à la micro-réseau. L'objectif est d'assurer la stabilité du système et d’améliorer les performances dynamiques en partageant la puissance entre les différents générateurs d’électricité distribués (DGs) en fonction de leur puissance nominale. Le développement d'une analyse de stabilité en boucle fermée s’avère utile pour étudier la dynamique du système afin d'obtenir une réponse transitoire souhaitée qui permet d'identifier les paramètres de contrôle de boucle appropriés. L'amélioration de la qualité d’énergie des micro-réseaux est également un objectif de cette thèse. La réduction des distorsions harmoniques de la tension de sortie en présence de charges linéaires et non linéaires est prise en compte dans nos travaux. D'autres aspects seront étudiés sur la façon de traiter les charges constantes connectées au réseau et les grandes perturbations qu’ils produisent. Cela donne lieu à d'autres études de recherche portant sur la stabilité grand signal des micro-réseaux<br>This thesis deals with islanded AC microgrid that allows any integration of Distributed Energy Resources (DERs) that may provide their existing supply energy in a controlled manner to insure overall system functioning. The interconnection of a DER to a microgrid is done usually by using a Distributed Interface Converter (DIC), a general power electronics interface block, which consists of a source input converter module, a Voltage Source Inverter module (VSI), an output interface module, and the controller module. The thesis realizes several control laws based on decentralized methods. The major focus is on the Droop functions that are responsible for providing a power distribution balance between different Energy Resources connected to a microgrid. The aim is to insure system stability and better dynamic performance when sharing the power between different DGs as function to their nominal power. Developing a closed loop stability analysis is useful for studying system dynamics in order to obtain a desired transient response that allows identifying the proper loop control parameters. Power Quality enhancement in microgrids is also a purpose of this research. The reduction of harmonic distortions of the output voltage when supplying linear and non-linear loads are taken in consideration in this thesis. Further aspects will be studied about how to deal with constant power loads connected to the grid and the large perturbations exerted. This results to further research studies that deal with large-signal stability of microgrids
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Göker, Fuat, and Christoffer Hedberg. "Utvärdering av faskompenseringsmetoder för ett småskaligt vattenkraftverk : Genomgång av kondensatorbatteri, aktiv och passiv reglering, övermagnetiserad synkronmaskin, SVC och STATCOM på Fröslida kraftverk." Thesis, KTH, Hälsoinformatik och logistik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230165.

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Småskalig vattenkraft är en stor användare av reaktiv effekt då de ofta har asynkrongeneratorer. Det gör att det finns ett reellt behov för faskompensering, dels för att minska distorsion i nätet samt för att förbättra deras ekonomiska ställning, då elbolag ofta tar ut en avgift för överskridande användning av reaktiv effekt. Det ligger också i allmänhetens intresse att ha en god elkvalitet och hålla störningar och avbrott nere, vilket kan erhållas med faskompensering och filtrering av övertoner. Det finns olika tekniker för faskompensering med sina respektive för- och nackdelar som specificeras efter anläggningens krav och förhållanden. Dessa tekniker är ett kondensatorbatteri, passiv och aktiv reglering, övermagnetiserad synkronmaskin, static var compensator (SVC) och static synchronous compensator (STATCOM). Med hjälp av simuleringar och ekonomisk kalkylering har deras egenskaper och investeringspotential analyserats. Det har resulterat i att ett kondensatorbatteri är en ekonomiskt god investering men med nackdelen att det blir en stor transient vid inkoppling. Aktiv reglering bistår med en snabb, kontinuerlig faskompensering men har större driftkostnader och en kortare livslängd. Övermagnetiserad synkronmaskin har en god ekonomisk framtidsutsikt men med en något långsammare reaktionstid. SVC och STATCOM är mer applicerbar på större anläggningar, eller för nät som har en större nytta av dess flexibilitet.<br>Small scale hydropower is a big user of reactive power, mainly because of their use of asynchrounous generators. Power companies are charging their customers a fee for an extensive use of reactive power. Which gives rise to a need of correction of the power factor as well as reduction of distorsion in the network. It is also in the interest of the general public to acquire a good electric quality in terms of keeping distorsion and interruptions in the network to a minimum. This can be achieved by using different methods for power factor correction and filtration of harmonics. These methods have their own inherent advantages and disadvantages described after the facility’s specific needs and requirements. These methods are a capacitor bank, passive and active regulation, overexcited synchronous machine, static var compensator (SVC) and static synchronous compensator (STATCOM). Simulations and economical calculations have been used to determine these properties. A capacitor bank has been proven to be a good economical investment, but it has high transients during switching conditions. Active regulation also shows a good profitability and provides a fast, continuous regulation of the reactive power, though it has higher operating costs and low life expectancy. The overexcited synchronous generator has a positive outlook in economic terms, with the drawback of a slower response time. SVC and STATCOM are more applicable to larger facilities or weak networks.
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28

Neužil, Jan. "Uživatelské rozhraní pro HP89410A." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217775.

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The aim of this thesis was to develop user interface in LabVIEW to make typical measurements with spectral analyzer HP89410A There is introduced the theory of operation of an analogue heterodyne and a digital FFT spectral analyzer. It is explained the background of the Fast Fourier Transform. There are discussed the key settings in measuring with FTT analyzer, like window function, bandwidth, number of frequency points, or the averaging. Further is described the program, which was developed for measuring frequency characteristic by white noise and by stepped measurement. It was also made a module for measuring Signal to Noise Ratio and module for Total Harmonic Distortion. In the last part of this thesis are shown the results of processed exemplar measurements.
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29

Lakomý, Marek. "Analýza provozu trakční napájecí stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220948.

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The work analyzes the operation of hybrid substations. The first chapter provides an analysis of domestic traction systems and describes in detail specific station. The next chapter follows the first in a way in which obtained parameters are converted to parameters suitable for the simulation program and presents its results. The third chapter discusses the serial communication used in one switchgear and about voltage regulator that controls one high voltage field. The last chapter verifies the simulation results obtained from the second chapter with real measurement and direct comparison is also included.
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30

Bissey, Sebastien. "Optimisation du coût de la consommation d'électricité dans l'habitat individuel." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4029.

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Les travaux menés durant cette thèse ont consisté à proposer des solutions pour optimiser le coût de la consommation d’électricité dans l’habitat individuel. Les outils matériels et logiciels proposés ici permettent à la fois d’estimer la rentabilité d’un système de gestion de l’électricité et l’impact des bons et simples gestes du quotidien. Dans un premier temps, des solutions permettant de faire des économies dans l’habitat individuel ont été comparées et évaluées. Le système de stockage de l’énergie électrique a été introduit. Le stockage permet entre autre de décaler la consommation d’électricité des heures pleines aux heures creuses et ainsi, de faire des économies. Dans une deuxième partie, la prédiction de la consommation d’électricité à base de logique floue a été introduite afin d’utiliser plus efficacement le système de stockage. La rentabilité des systèmes de stockage et des prises « connectées » a été étudiée. Dans un troisième et dernier temps, un convertisseur statique d’énergie à haut rendement (supérieur à 95%) a été introduit. Ce dernier est nécessairement bidirectionnel car l’énergie doit pouvoir transiter du système de stockage vers le réseau électrique de distribution et vice versa. Les taux de distorsion harmonique des signaux doivent alors être les plus petits possibles (ici, inférieurs à 8%). L’originalité du convertisseur proposé réside aussi dans la simplicité des commandes numériques nécessaires. Les composants sur substrat en SiC ont été utilisés pour atteindre les rendements souhaités. Ces composants permettent aussi d’augmenter la fréquence de découpage et ainsi, de diminuer la taille des éléments de filtrage<br>The work carried out as part of this thesis con'sisted in proposing solutions to optimize the cost of electricity consumption in individual housing. The hardware and software tools proposed here make it possible to estimate both the profitability of an electricity management system and the impact of good and simple daily actions. First, some solutions to save money in the single-family home were compared and evaluated. The electrical energy storage system has been introduced. Storage makes it possible, among other things, to shift electricity consumption from peak to off-peak hours and thus save money. In a second part, the prediction of electricity consumption based on fuzzy logic was introduced in order to use the storage system more efficiently. The profitability of storage systems and smart plugs was studied. In a third and final part, a highly efficient energy converter (above 95%) was introduced. The latter is necessarily bidirectional because the energy must be able to pass from the storage system to the distribution network and vice versa. The harmonic distortion rates of the signals must then be as low as possible (here, less than 8%). The originality of the proposed converter also lies in the simplicity of the necessary digital control circuits. SiC power devices were used to achieve the desired energy efficiency values. These components also increase the switching frequency and thus reduce the size of the filter elements
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31

Pelteku, Altin E. "Adaptive Suppression of Interfering Signals in Communication Systems." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-dissertations/138.

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The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.
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32

Kerzerho, Vincent. ""Analogue Network of Converters": a DfT Technique to Test a Complete Set of ADCs and DACs Embedded in a Complex SiP or SoC." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2008. http://tel.archives-ouvertes.fr/tel-00364546.

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Une nouvelle méthode de test pour les convertisseurs ADC et DAC embarqués dans un système complexe a été développée en prenant en compte les nouvelles contraintes affectant le test. Ces contraintes, dues aux tendances de design de systèmes, sont un nombre réduit de point d'accès aux entrées/sorties des blocs analogiques du système et une augmentation galopante du nombre et des performances des convertisseurs intégrés. La méthode proposée consiste à connecter les convertisseurs DAC et ADC dans le domaine analogique pour n'avoir besoin que d'instruments de test numériques pour générer et capturer les signaux de test. Un algorithme de traitement du signal a été développé pour discriminer les erreurs des DACs et ADCs. Cet algorithme a été validé par simulation et par expérimentation sur des produits commercialisés par NXP. La dernière partie de la thèse a consisté à développer de nouvelles applications pour l'algorithme.
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33

Yan, Jun. "A Low Total Harmonic Distortion Sinusoidal Oscillator Based on Digital Harmonic Cancellation Technique." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11204.

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Sinusoidal oscillator is intensively used in many applications, such as built-in-self-testing and ADC characterization. An innovative medical application for skin cancer detection employed a technology named bio-impedance spectroscopy, which also requires highly linear sinusoidal-wave as the reference clock. Moreover, the generated sinusoidal signals should be tunable within the frequency range from 10kHz to 10MHz, and quadrature outputs are demanded for coherent demodulation within the system. A design methodology of sinusoidal oscillator named digital-harmonic-cancellation (DHC) technique is presented. DHC technique is realized by summing up a set of square-wave signals with different phase shifts and different summing coefficient to cancel unwanted harmonics. With a general survey of literature, some sinusoidal oscillators based on DHC technique are reviewed and categorized. Also, the mathematical algorithm behind the technique is explained, and non-ideality effect is analyzed based on mathematical calculation. The prototype is fabricated in OnSemi 0.5um CMOS technology. The experimental results of this work show that it can achieve HD2 is -59.74dB and HD3 is -60dB at 0.9MHz, and the frequency is tunable over 0.1MHz to 0.9MHz. The chip consumes area of 0.76mm2, and power consumption at 0.9MHz is 2.98mW. Another design in IBM 0.18um technology is still in the phase of design. The preliminary simulation results show that the 0.18um design can realize total harmonic distortion of -72dB at 10MHz with the power consumption of 0.4mW. The new design is very competitive with state-of-art, which will be finished with layout, submitted for fabrication and measured later.
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34

Luo, Shih-Chung, and 羅世崇. "Estimating Total-Harmonic-Distortion of Analog Signal in Time-Domain." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/54418096252022565708.

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碩士<br>國立雲林科技大學<br>電子與光電工程研究所碩士班<br>100<br>In this work, we propose a methodology to estimate Total-Harmonic-Distortion (THD) in time domain. Instead of using Fast-Fourier-Transform (FFT), we express the signal under test into Taylor expansion and derive the relationship between coefficients of Taylor series and composition of harmonic. Furthermore, through analyzing syndromes on signal under test with respect to coefficients of Taylor series and extracting effective information, we calculate these coefficients and translate into harmonic distortion by Parseval’s theorem. The required instrument of proposed method is oscilloscope which is more conventional than spectrum analyzer. Especially for those low speed voice or physiology analog signals, the required spectrum analyzer is particular and expensive. In addition, the stability of THD estimation by proposed method is better than FFT which its accuracy is proportional to quantity of samples.
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35

Weng, Kun-Yao, and 翁崐耀. "Improvement of Total Harmonic Distortion of Elliptical Microspeakers using Speaker Nonlinearities." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/90154499473935167658.

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碩士<br>逢甲大學<br>電聲碩士學位學程<br>98<br>Electrodynamic (moving-coil) transducer such as loudspeaker is subjected to distortion during performance mainly due to nonlinearities. Major nonlinearities are motor and suspension nonlinearities, Bl(x) and Km(x), respectively, which are displacement dependent. Force factor Bl(x) and mechanical suspension stiffness Km(x) nonlinearities are investigated in this thesis for elliptical loudspeaker with various magnetic circuits and track patterns. Analytical modeling and finite element method (FEM) are used to investigate these nonlinearities. For Bl(x) nonlinearities, the FEM commercial software COMSOL and Klippel measurement system in air and vacuum are performed. To validate the simulation by COMSOL and the measurement by Klippel, Tytron 250 micro tensile testing is employed to obtain force factor-displacement dependence. Sound pressure level (SPL) and total harmonic distortion (THD) measurements and simulations are consequently obtained. In order to reduce THD, simulation has been carried out for under-yoke size variations and it is confirmed by anechoic chamber measurements. Promising results are obtained for increase in size of under-yoke by 0.2 mm. Similar methodology is adopted for polar piece and magnet size variations keeping combined height of polar piece and magnet as a constant. Good results are obtained for decrease in size of polar piece by 0.1 mm and corresponding increase in size of magnet. For Km(x) nonlinearities the same approach is applied. Klippel measurement yielded discrepancy between air and vacuum measurements. Theoretical modeling of Km(x) is done and Km(x) effect on THD is investigated. Simultaneously, simulations are carried out using the other FEM commercial software ANSYS and corresponding THD is obtained. In order to reduce THD, various track patterns along with no track on diaphragm are explored. Results indicate that curved track pattern possesses lower THD than straight-full track pattern. Similarly, straight-partial track pattern shows lower THD than straight-full track pattern. It is concluded that the trend of Bl(x) and Km(x) could be used to choose the most appropriate suspension and magnetic circuit for microspeaker. Designing of a microspeaker with desired SPL and THD by using the distortion model developed in this work is emphasized. Last but not least, we have proposed certain design rules based on our findings to reduce the time and cost during product design and development.
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Chen, Yong-Han, and 陳泳翰. "Analysis of Power Factor and Total Harmonic Distortion of Single-Phase Full-Wave Rectifier." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/53778025064598490584.

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碩士<br>崑山科技大學<br>電機工程研究所<br>101<br>Most electronic circuits and devices need the supply of direct current source. However, generally, the energy transmitted by electric power companies to users is alternating current(as far as Taiwan region is concerned, that is AC 110V/ 60Hz). So, according to circuit demand, most users have to get suitable voltage supply through the step-down and boost of transformer.Through the transition of transformer, actually, alternating current has to pass two steps of rectifier and filter, then users can get direct current source. The thesis mainly uses analog circuit to finish the analysis of Power Factor and Total Harmonic Distortion of single-phase full-wave rectifier, using the advantages of full-wave rectifier, such as small ripple and less quantity of elements, to make AC/DC conversion. In addition, the thesis also analyzes the impact of different capacitance values on power factor and current harmonics. Finally, experiment results are used to verify the feasibility of system and theory suggested by the thesis. In the course of verification, comparison ismade between experiment data and IEEE/Std 519-1992 harmonic standards.
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37

Yang, Chih-Hsiang, and 楊智翔. "Comparing Total Harmonic Distortion for Cascade Multilevel Active front-end Converters with Low Carrier Ratio." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/he4c5x.

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碩士<br>中華大學<br>電機工程學系<br>104<br>Active Front End converter (AFE) having a controllable DC voltage, controllable power factor, bidirectional power flow control and low harmonic distortion of the phase current, it can achieve requirements of IEEE 519- 1992, IEC 6100-3-2 and other industry specifications to avoid voltage and current drops leaving the power quality when the power system contain non-linear loads. The architecture of multi-level inverter reduce the total harmonic distortion for achieve a higher quality of the power system effectively. So the architecture has gradually replace the traditional diode bridge rectifiers applied to the motor drive on. Because consideration of traditional inverters size and the design of filter tend to increase its switching frequency to reduce the size of its inductor, but in hard switching system, it’s also resulting in increased switching loss. This paper uses a cascade H-bridge multi-level active front-end converter architecture with different low carrier ratio (nine times, fifteen times, twenty times), to discuss the total harmonic distortion and harmonics component. The low-carrier ratio modulation method is proposed in this context, and it compare with the traditional Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM).
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38

Chang, Chun, and 張鈞. "Reduction of the Total Harmonic Distortion of a Moving-Coil Loudspeaker by Initially Repositioning its Voice Coil." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/78626355601104271775.

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碩士<br>逢甲大學<br>電聲碩士學位學程<br>100<br>The nonlinear effect of a moving-coil loudspeaker, originating from its magnetic coupling factor and the system’s stiffness, presents a significant impact on the sound quality. For improving the sound quality, this article proposes an approach to reduce the total harmonic distortion (THD) by adjusting the initial position of its voice-coil. First, a mathematical model involving the nonlinearities of force factor, mechanical stiffness, and inductance of voice coil is constructed and then solved using a novel algorithm called the parameter spline difference method (PSD). In the course of pursuing reduction of the corresponding THD of a typical moving-coil loudspeaker, the model was used to analyze the nonlinearity of the THD, revealing itself as a nonlinear function of force factor, the system’s stiffness and inductance of voice coil. For various initial positions of the voice-coil, the coupled nonlinear differential equations were solved using the PSD to yield corresponding sound pressure level and THD. To our satisfaction, the loudspeaker driver with its voice-coil optimally tuned for the initial position turns out to have a THD reduction of 10%, which is also consistent with our experimental observations.
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39

Zhou, Hua. "Harmonic current control in a high-power current source rectifier system." Master's thesis, 2011. http://hdl.handle.net/10048/1702.

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Line current distortion is an important issue to a high-power current source rectifier(CSR) system. There are two main challenges related to this issue. First, the CSR input LC resonance can be affected by the variation of the source inductance from the power system and the effects of the CSR DC side circuit, which may lead to a line current distortion higher than expected. Another challenge is that the traditional high-power CSR using Selective Harmonic Elimination (SHE) pulse-width modulation (PWM) technique attempts to eliminate certain harmonics in the PWM current, which limits its ability for line current harmonic control. To control the CSR line current harmonics, this thesis focuses on two aspects: 1) the analysis and design of CSR input filter to avoid unexpected input LC resonance, and 2) the development of a new PWM scheme that can compensate the effects of the grid voltage harmonics and DC link current ripples. The thesis work has been validated by simulations and on an experimental CSR prototype.<br>Power Engineering and Power Electronics
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40

Ni, Chia-Lung, and 倪嘉隆. "0.99 PF and 1.7% THD by Line Voltage Recovery and Total Harmonic Distortion Optimizer in Power Factor Correction Controller." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/54jh26.

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碩士<br>國立交通大學<br>電控工程研究所<br>101<br>As populations increase and countries industrialize, the world’s demand for energy increases. In recent years, the energy-shortage problem becomes more serious. Therefore, the issue of green power is respected gradually. Power factor correction (PFC) can shape the input current of off-line power supplies to be in-phase with the input AC voltage in order to maximize the available real power from the AC source to achieve high power factor (PF). The total harmonic distortion (THD) of input current is an important factor for PF. Considering high power factor (PF) and efficiency, the boundary conduction mode (BCM) control is more suitable for low-power applications such as the adapter and lighting. However, there are two major THD-deteriorated contributors in a conventional PFC boost converter with BCM control. One is the crossover distortion caused by the diode’s forward voltage in the bridge and parasitic capacitances. The other is the line frequency reflected distortion. Because the harmonic current can interfere with other electronic equipment seriously, there are many international standards to limit harmocin current. In order to conform the harmonic-current standards stricter and stricter, an improving THD technique is proposed in this thesis. The proposed line voltage recovery (LVR) and the total harmonic distortion optimizer (THDO) improve PF and THD over a wide line voltage range. The LVR detects the input line root-mean-square (rms) voltage to generate the digital equivalent code to the THDO for optimizing the THD by tuning the on-time value at different line voltages. Besides, the LVR and the THDO provide a feedforward path to reduce the ripple of the feedback voltage for further improving the THD. Therefore, the PFC controller can keep high PF and low THD over a wide line voltage. Experimental results demonstrate the PF is higher than 0.99 and the THD is 1.7% at VAC of 90 - 110V by the test circuit fabricated in TSMC 800V UHV process.
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41

蔡仁杰. "High Efficiency and Low Total Harmonic Distortion Power Factor Correction Controllers with Automatic Loading Detection and Perturbation On-time Techniques." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/89786690166223606347.

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博士<br>國立交通大學<br>電控工程研究所<br>100<br>The power factor correction (PFC) controller is more popular in today’s green power mainstream for improving power utilization efficiency. The power factor correction shapes the input current of off-line power supplies to increase the real power available from the AC source. First, the proposed perturbation on-time (POT) technique suppresses total harmonic distortion (THD) and thus improves the power factor (PF) in the power factor correction (PFC) controller. Besides, the adaptive controls of the minimum off-time by the proposed inhibit time (IT) control can improve efficiency even at low AC input voltage. Therefore, highly integrated PFC converter fabricated in the TSMC 800-V ultrahigh voltage process can achieve low THD of 6%, high power factor (PF) of 99%, and high efficiency of 95% at the output power of 90W. Second, the proposed automatic loading detection (ALD) technique keeps high efficiency in interleaving PFC over a wide load range. With the advantages of small input/output filter and output ripple in the interleaving mechanism, the improved efficiency by the ALD technique at light loads due to reduced switching loss can be widely used in the adapter of portable electronics. The ALD technique can calculate the power by the detection of peak input voltage to reduce the switching loss since the slave channel can be completely turned off for power saving at light loads. Therefore, the boundary control mode (BCM) control can simultaneously provide high power and keep high conversion efficiency both at light and heavy loads. The highly integrated PFC controller fabricated in TSMC 800V UHV process shows high efficiency of 92% over a wide output power of 180 W.
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42

Yang, Jen-Hua, and 楊仁華. "Design and Implementation of an Active LED Driver Scheme with High Power Factor and Extra-Low Total Harmonic Distortion of Input Current." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/yyh3a7.

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碩士<br>中原大學<br>電機工程研究所<br>102<br>In this thesis, a scheme with high power factor and extra-low total harmonic distortion of input current is implemented in AC-DC LED driver based on Primary Side Regulation (PSR). It achieves the performance of high Power Factor (PF) and extra-low Total Harmonic Distortion of Input current (THDi), and operates in Boundary Conduction Mode (BCM). We adopt the structure of the improved PSR converter scheme by using SD6800 to implement the design. How to improve PF and THDi will be described. The analysis and design of our SD6800 application circuit are explained here. Furthermore, it will show time-domain analysis of our proposed converter circuit to achieve high PF and extra-low THDi by operating in BCM. Finally, the performance comparison of PSR converter operated in Boundary Conduction Mode with Continuous Conduction Mode (CCM) will be discussed. Some contributions are presented here : 1. To get high power factor greater than 0.95; 2. To achieve extra-low total harmonic distortion of input current less than 10%; 3. Due to based on primary side regulation scheme, the cost is more cheaper than secondary side regulation scheme. The performances of high PF and extra-low THDi are more and more important in LED lighting market, especially for some precise-instruments and susceptible production-lines in the same power supply. To get the better energy utilization and to avoid the harmonic interferences, the LED driver with high PF and extra-low THDi is the major-trends in the lighting market now and future.
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43

Chien, Shih-Hai, and 錢世海. "A Study on Calculating the Optimal Turn-on Angle of Multilevel Cascade Inverter with Particle Swarm Optimization to Reduce Total Harmonic Distortion and the Verification of Hardware-in-the-loop." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/31463317801239457041.

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碩士<br>國立聯合大學<br>電機工程學系碩士班<br>102<br>The optimal switch conduction angle to solve the cascade multilevel inverter is regarded as the research subject in this study. The voltage on the power switches of a cascade multilevel inverter could be applied to high-power environments. Nevertheless, it is necessary to use the modulation strategy to have the output waveform approach sine waves, where the harmonic optimization staircase waveform strategy in step modulation could reduce the switching frequency. However, nonlinear equations need to be solved for calculating the optimal switch conduction angle. A rapid solving algorithm is required for the real-time application. To rapidly solve the optimal switch conduction angle for the harmonic optimization staircase waveform of a cascade multilevel inverter, a modified particle swarm optimization, which combines standard particle swarm optimization and complementary particle swarm optimization, is proposed in this study, where the objective function applies the sum of squares of KKT prerequisite for satisfying the harmonic optimization. The optimization is implemented with MATLAB and FPGA hardware-in-the-loop, and Simulink is used for constructing the cascade multilevel inverter model for the simulation and analysis efficacy. Since total harmonic distortion calculation and square root calculation are avoided in the objective function and the particle velocity update is improved, the proposed method appear faster speed of convergence than standard particle swarm optimization does.
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44

Παπανικολάου, Κωνσταντίνα. "Επίδραση κατανεμημένων παραγωγών στη λειτουργία συστήματος ηλεκτρικής ενέργειας". Thesis, 2014. http://hdl.handle.net/10889/8420.

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Στην παρούσα διπλωματική εργασία πραγματοποιείται μελέτη της επίδρασης ενός συστήματος διασύνδεσης ανεμογεννήτριας με το δίκτυο μέσης τάσης, όσον αφορά την έγχυση αρμονικών από την ανεμογεννήτρια προς το δίκτυο. Η μελέτη περιλαμβάνει τη μοντελοποίηση κάθε τμήματος ενός δικτύου μέσης τάσης με πραγματικά στοιχεία που πάρθηκαν από τη ΔΕΗ. Επιπλέον, μοντελοποιείται μια ανεμογεννήτρια τύπου σύγχρονης μόνιμων μαγνητών, καθώς και όλοι οι ηλεκτρονικοί μετατροπείς ισχύος που απαιτούνται για τη διασύνδεση αυτής με το δίκτυο μέσης τάσης. Όλα τα επιμέρους μοντέλα διασυνδέονται μεταξύ τους ώστε να αποτελέσουν το συνολικό μοντέλο που περιλαμβάνει το δίκτυο μέσης τάσης με τις γραμμές μεταφοράς, τους μετασχηματιστές, τα φορτία και τους πυκνωτές αντιστάθμισης που διαθέτει και την ανεμογεννήτρια μαζί με τους μετατροπείς συνδεδεμένη σε ένα ζυγό του δικτύου. Από το μοντέλο αυτό εξάγεται το αρμονικό περιεχόμενο τόσο στο ζυγό της ανεμογεννήτριας όσο και σε διπλανούς ζυγούς και συγκρίνεται κάθε φορά με το πρότυπο IEC 61000-3-6 που θέτει τα όρια για την έγχυση αρμονικών στο δίκτυο μέσης τάσης. Αρχικά, γίνεται μια αναφορά στα πλεονεκτήματα της αιολικής ενέργειας έναντι των άλλων συμβατικών μορφών ενέργειας. Επιπλέον, αναφέρονται τα προβλήματα που δημιουργούνται από την παρουσία ανώτερων αρμονικών στο δίκτυο. Έπειτα, πραγματοποιείται θεωρητική ανάλυση κάθε τμήματος του δικτύου μέσης τάσης. Για κάθε τμήμα δημιουργείται, επίσης, ένα μοντέλο στο Matlab/Simulink που βασίζεται σε στοιχεία από τη ΔΕΗ και εξισώσεις που αφορούν το εκάστοτε τμήμα. Στη συνέχεια, αναλύεται και μοντελοποιείται στο Matlab/Simulink και κάθε τμήμα του συστήματος διασύνδεσης της ανεμογεννήτριας με το δίκτυο μέσης τάσης που περιλαμβάνει την ανεμογεννήτρια τύπου σύγχρονης μόνιμων μαγνητών, ανορθωτική διάταξη, μετατροπέα συνεχούς τάσης σε συνεχή, τριφασικό αντιστροφέα, φίλτρο και μετασχηματιστή. Για κάθε μετατροπέα αναλύεται και μοντελοποιείται και έλεγχος κλειστού βρόχου. Τέλος, τα επιμέρους μοντέλα συγκροτούνται σε ένα συνολικό μοντέλο. Μεταβάλλοντας το συντελεστή φόρτισης των μετασχηματιστών του δικτύου, το συντελεστή ισχύος και το πλήθος των ανεμογεννητριών που συνδέονται στον ίδιο ζυγό, εξάγεται το αρμονικό περιεχόμενο για διάφορους ζυγούς και ελέγχεται αν αυτό συμφωνεί με το πρότυπο IEC 61000-3-6. Επιπλέον, εξετάζεται το αρμονικό περιεχόμενο της τάσης, όταν ο ζυγός διασύνδεσης αλλάζει θέση μέσα στο υπό μελέτη δίκτυο, καθώς και όταν αλλάζει η ταχύτητα του ανέμου.<br>In the present diploma thesis a study of the effect of a wind turbine system interconnection with medium voltage grid is conducted, in terms of harmonic injection of the turbine to the grid. The study includes the modeling of each part of a medium voltage grid with actual data taken from the Public Power Corporation of Greece. Furthermore, a synchronous wind turbine with permanent magnets is modeled along with all the electronic power converters that are required for the interconnection with the medium voltage grid. All the individual models are connected together to form the overall model, including the medium voltage transmission lines, transformers, loads and their compensation capacitors, along with the wind turbine and the power converters. The wind turbine is connected in a bus of the medium voltage grid. Then, the harmonic content in both the bus of the wind turbine and in other buses of the grid is extracted and compared with the standard IEC 61000-3-6 that sets the limits for harmonic injection in medium voltage grid. Initially, the advantages of use of wind energy are mentioned compared to other conventional forms of energy. Furthermore, the problems caused by the presence of harmonics in the grid are discussed. A theoretical analysis of each section of the medium voltage grid is conducted. For each section, a model in Matlab / Simulink is also created, based on data from the Public Power Corporation of Greece and on equations related to each section. Then, every part of the system connecting the wind turbine to the medium voltage grid is analyzed and modeled in Matlab/Simulink. This system consists of a synchronous wind turbine with permanent magnets, DC-to-DC converter, three-phase inverter, filter and transformer. A closed loop control for each converter is also analyzed and modeled. Finally, the aforementioned models are built up into one single model. By varying the load factor of the grid transformers, the power factor and the number of wind turbines connected to the same bus, the harmonic content of various buses is extracted and checked if it complies with the standard IEC 61000-3-6. Moreover, the harmonic content of the voltage is calculated, when the system of wind turbine changes position in the present medium voltage grid, as well as when the wind speed is changed.
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45

Pereira, Carlos Frederico Sousa. "Efeitos dos harmónicos nos contadores de energia." Master's thesis, 2013. http://hdl.handle.net/1822/41961.

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Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores<br>É cada vez mais importante nos dias de hoje utilizar a energia disponível da melhor forma possível. A maneira como se utiliza irá determinar a magnitude do impacto no meio ambiente. Por estas razões, a qualidade da energia elétrica tornou-se um tópico fundamental nestes últimos anos. Com o desenvolvimento da eletrónica de potência e com uma maior consciencialização em torno dos diferentes problemas de qualidade de energia, é imperativo investigar os efeitos da distorção harmónica nos medidores de energia. Torna-se, por isso, pertinente aprofundar e ampliar o conhecimento sobre harmónicos e sobre as suas consequências em todo o tipo de equipamentos eletrónicos. Este aspeto granjeou ainda mais importância com a difusão da utilização das cargas não lineares. O objetivo desta dissertação é descobrir os efeitos dos harmónicos nos contadores de energia elétrica de baixa tensão. Nos dois tipos de medidores de energia elétrica mais utilizados (eletromecânico e digital), os efeitos da distorção harmónica são bastante mais percetíveis nos contadores eletromecânicos, mesmo quando são submetidos ao mesmo tipo de cargas e condições semelhantes. Regra geral, os contadores digitais são bastante mais precisos e exatos do que os eletromecânicos [1]. A diferença entre eles poderá não ser muito relevante em baixa tensão, mas para média tensão deve ser considerada, principalmente para consumidores industriais. Esta diferença deve-se ao facto de serem calibrados para serem utilizados em condições sinusoidais, o que não acontece [2]. O disco que contêm no interior faz a medição através de duas bobinas, uma de corrente e outra de tensão. A bobina de tensão é constituída por muitas espiras e fio fino, sendo colocada em paralelo com a carga para ser submetida à mesma tensão. A bobina de corrente é composta por poucas espiras e fio grosso pois irá ter a mesma corrente que a carga. Os campos magnéticos gerados pela corrente alternada geram correntes parasitas, que por sua vez serão induzidas no disco fazendo-o girar. Em zonas puramente industriais onde este tipo de contadores ainda estão a ser utilizados, este valor deverá ser naturalmente superior, pois a distorção harmónica é mais visível perto da carga [3], dando uma importância acrescida a este tópico. O que deverá ser feito numa primeira fase, é uma comparação entre os dois aparelhos em baixa tensão, comparando os valores de energia obtidos em diferentes aparelhos habituais no setor residencial, bem com uma análise de custos para se poder verificar se a mudança de sistema de medição é ou não compensatória. Durante a realização dos testes experimentais, foi verificada uma diferença entre os aparelhos utilizados. O contador eletromecânico registou, quase sempre, valores superiores de potência ativa fundamental quando comparado com os registados pelo analisador de qualidade de energia. Depois, foi realizada uma montagem para elevar a distorção da tensão de alimentação, tendo como resultado erros negativos em praticamente todos os casos.<br>It is very important, nowadays, to use the available energy in the best possible way. The way we use it will determine the magnitude of our impact on the environment. Due to this, power quality has become a very important topic in the last few years. Adding this to the great developments in power electronics and an increase in awareness about all the issues relating to power quality, it is now imperative to investigate the effects of harmonic distortion on energy meters. Taking this into consideration, the knowledge about harmonics should be enhanced as well as the knowledge about their effects on electronic devices. This topic has gained extra importance with the widespread use of non-linear electronic equipment. The objective of this dissertation is to find out the differences between the two most widely used ways of measuring electrical energy in the low-voltage grid: electro-mechanical energy meters and digital energy meters. Usually digital meters are more accurate than the electro-mechanical ones. It's possible that the difference between them might not be relevant but at medium voltages it must be considered, especially for industrial consumers. The objective here is to find out how much more accurate digital meters are and also to find out the cases in which the replacement should be carried out or not. Different types of loads will be analyzed and a comparison between the two energy meters types will be performed. The measurement is carried out by a rotating disc which rotates under the influence of the induced eddy currents. These currents appear due to the oscillating magnetic field created by two coils, one for current and another for voltage. The voltage one is composed of many windings and thin wire, whilst the current coil only has a few windings and thick wire. A search to find the harmonics which are more prejudicial to the operation of the electro-mechanical devices will be performed as well. The economic impact of these measurements should be studied in order to ascertain who might or might not be interested in a replacement and how much the annual savings can be. The dfference between the digital and analog devices was verified, and in almost all situations there was an over registration of the fundamental active power by the analog device. After, a experimental setup was carried out in order to raise the voltage THD. The verified error was mostly negative under these conditions.
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46

Brolund, Andreas. "Evaluation of power quality and common design concept for AC-DC converters in aircraft." Thesis, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-337969.

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This master thesis has been carried out in collaboration with Saab, Avionics Systems in Jönköping, Sweden, during the spring of 2017. The thesis investigates unidirectional rectifier topologies in aircraft and the focus has been on evaluating the power quality requirements according to the aircraft standards, in the course of the More Electric Aircraft concept. Both passive and active power factor correction topologies are considered, discussed and compared. Simulation models are designed in MATLAB/Simulink and the procedures are presented. A modular concept regarding components is discussed where different power supplies and loads are considered. The simulations present both a passive 12-pulse auto-transformer rectifier unit and an active Delta-switch rectifier fulfilling requirements for aircraft such as the total harmonic distortion of the supply current. In addition, the input power factor is close to unity and an efficiency greater than 97% is obtained. Lastly, future aspects of each topology are discussed and necessary improvements to obtain realistic simulation models are presented.
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