Dissertations / Theses on the topic 'Snubber'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Snubber.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Lima, Luiz Ricardo. "Inversor monofásico NPC com snubber regenerativo." Universidade do Estado de Santa Catarina, 2011. http://tede.udesc.br/handle/handle/2089.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work presents a study about the NPC (Neutral Point Clamped) three-level inverter with a modified Undeland snubber and using a Buck-Boost converter to regenerate the energy processed by the snubber. Initially, qualitative and quantitative analysis of this inverter with the presence of the snubber are presented and a project methodology is proposed. The same analysis and project are presented for the Buck-Boost converter and it is shown that this converter can operate under ZVS (Zero Voltage Switching). Next, mathematical models of all circuitry necessary for the realization of the digital control of the inverter are presented and a controller is projected. Using data of the projected NPC inverter, Buck-Boost converter and digital controller, simulation results are presented. These simulations were done using software s Orcad Pspice and Simulink. Finally, implementation details and experimental results of a 1.5 kW, 800 V input voltage, 127 V output voltage and 200 kHz switching frequency prototype are presented.
Este trabalho apresenta um estudo do inversor NPC (Neutral Point Clamped) a três níveis com snubber de Undeland modificado, utilizando um conversor Buck-Boost para regeneração da energia processada pelo snubber. Inicialmente são feitas analises qualitativa e quantitativa desse inversor com a presença do snubber e é apresentada uma metodologia de projeto. As mesmas analises e projeto são feitos para o conversor Buck-Boost e é mostrado como ele pode operar com comutação ZVS (Zero Voltage Switching). A seguir são mostrados os modelos matemáticos de todos os circuitos necessários para se realizar o controle digital do inversor e é apresentado um projeto de controlador digital. Utilizando os dados de projeto do inversor NPC, do conversor Buck-Boost e do controle são apresentados os resultados de simulações feitas nos programas Orcad Pspice e Simulink. Por ultimo, são apresentados detalhes de implementação e resultados experimentais de um protótipo de 1,5 kW, 800 V de tensão de barramento, 127 V de tensão de saída e 200 kHz de freqüência de comutação.
Wei, Yu. "A Novel Auxiliary Resonant Snubber Inverter Using Wide Bandgap Devices." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83238.
Full textMaster of Science
Faraci, William Eric. "Design of a Resonant Snubber Inverter for Photovoltaic Inverter Systems." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47800.
Full textMaster of Science
Chen, Yen-Ming. "RC Snubber Design using Root-Loci Approach for Synchronous Buck SMPS." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/963.
Full text姚建明 and Jianming Yao. "Control schemes and performance improvement of resonant snubber soft-switching inverters." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31220198.
Full textYao, Jianming. "Control schemes and performance improvement of resonant snubber soft-switching inverters /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2051007X.
Full textTang, Yuqing. "High Power Inverter EMI Characterization and Improvement by Auxiliary Resonant Snubber Inverter." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/31022.
Full textIn this paper, the relation between the dv/dt di/dt and the EMI generation are discussed. The EMI sources of a hard-switching single-phase PWM inverter are identified and measured with separation of common-mode and differential-mode noises. The noise reduction in an auxiliary resonant snubber inverter (RSI) is presented. The observation of voltage ringing and current ringing and the methods to suppress these ringing in the implementation of RSI are also discussed. The test condition and circuit layout are described as the basis of the study. And the experimental EMI spectra of both hard- and soft-switching inverter are compared. The effectiveness and limitation of the EMI reduction of the ZVT-RSI are also discussed and concluded.
The control interface circuit and gate driver design are described in the appendix. The implementation of variable charging time control of the resonant inductor current is also explained in the appendix.
Master of Science
Combrink, Frederik Wilhelm. "Analysis and synthesis of an active resonant snubber for high-power IGBT converters." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52090.
Full textENGLISH ABSTRACT: This thesis describes the study of two soft-switching inverter topologies that are well suited to high-power applications. For the first topology, namely an active resonant turn-off snubber, the existing theory is expanded with a detailed study into operation strategies and topology protection. This is followed by an investigation into the second topology, which is a combined snubber that reduces both turn-off and turn-on losses. The investigation involves a detailed analysis of the losses in the snubber components and main devices, as well as a study into the effects of parasitic components and diode reverse recovery on the operation of the snubber. Based on this theory a snubber optimisation procedure is also developed. Possible operation strategies and protection techniques were also evaluated for this topology. Single-phase experimental inverters were used to verify the basic operation theory and switching loss prediction for both topologies. The thesis is concluded by the design and construction of a practical soft-switching threephase inverter. After implementation the experimental inverter is used for theory verification.
AFRIKAANSE OPSOMMING: Hierdie proefskrif beskryf die ondersoek na twee saggeskakelde omsetter topologieë wat veral geskik is vir hoë-drywing toepassings. Die bestaande teorie aangaande die eerste topologie, naamlik 'n aktiewe, resonante, afskakel gapser, word uitgebrei met 'n deeglike-studie oor bedryfstegnieke en beskermingsmetodes. Vervolgens word 'n gekombineerde gapser topologie, wat beide aanskakel- en afskakelverliese verminder, ondersoek. Die studie behels 'n volledige analise van die verliese in die omsetter en gapser komponente en die invloed van parasitêre komponente en diode tru-herstel. Hierdie teorie word ook gebruik om 'n optimale gapser ontwerp prosedure te ontwikkel. Die moontlikke bedryfstegnieke en beskermingsmetodes word ook vir hierdie topologie evalueer. In albei gevalle is eksperimentele, enkelfase omsetters gebruik om die teorie oor basiese werking en skakelverlies vermindering te verifieer. Die ondersoek word afgesluit deur die ontwerp en konstruksie van 'n praktiese, saggeskakelde, drie-fase omsetter te beskryf. Na implimentering van die omsetter word volledige eksperimentele verifikasie uitgevoer.
Novaes, Yales Rômulo de. "Estudo de um Snubber para o inversor de três níveis com netro grampeado." Florianópolis, SC, 2000. http://repositorio.ufsc.br/xmlui/handle/123456789/79250.
Full textMade available in DSpace on 2012-10-18T00:59:22Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-25T18:45:10Z : No. of bitstreams: 1 182239.pdf: 4426878 bytes, checksum: 85f08d8cd86db634a6d92cbdfba27250 (MD5)
Este trabalho apresenta o estudo do inversor Três Níveis, também conhecido como inversor com ponto neutro grampeado, da sigla inglesa N.P.C. Inicialmente, são explicados os princípios de funcionamento do inversor, através da utilização da estratégia de modulação por largura de pulso único. A seguir, são apresentadas e comparadas qualitativamente as demais técnicas de modulação existentes na literatura, para aplicação ao inversor Três Níveis. É apresentada a análise teórica, primeiramente demonstrando o equacionamento dos esforços de corrente nos interruptores do inversor, desconsiderando as comutações. Em seguida, a aplicação da técnica passiva de comutação suave, conhecida como Snubber de Undeland (modificado), é explorada detalhadamente. Ao final, tem-se os resultados da experimentação de um inversor de 10 kVA, comutando a uma freqüência de 20 kHz. Diante dos resultados apresentados, são mencionados os efeitos causados pelos componentes parasitas existentes em um circuito real. São, também, comentados os aspectos positivos e negativos da utilização do snubber ao inversor.
Ngatu, Grum T. "Development of a snubber type magnetorheological fluid elastomeric lag damper for helicopter stability augmentation." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9326.
Full textThesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Sperb, Jonathan Dômini. "Projeto de um inversor trifásico com snubber de undeland regenerativo e controle digital implementado no DSP TMS320F2812." Universidade do Estado de Santa Catarina, 2007. http://tede.udesc.br/handle/handle/1886.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work deals with the design and implementation of the digital instantaneous averaged values control for output voltages of the three-phase inverter with Underland s snubber, using the Buck-Boost converter for regeneration of the snubber s energy. The qualitative and quantitative analysis of the inverter power structure, snubber and auxiliary converter, as well as the project for a set of presented specifications is presented. All needed block models for the design of the control are shown, as well as the project methodology of frequency response control. Results of simulation complement the work and prove the presented methodology. For experimental validation, it s developed a three-phase inverter with snubber and auxiliary converter, with output power of 4.5kVA, switching frequency of 50kHz, and with capacity to operate with full power for output voltage from 127V up to 220V. Experimental results of the power circuits and control performance complement the study.
Este estudo trata do projeto e implementação do controle digital por valores médios instantâneos das tensões de saída do inversor trifásico com Snubber de Undeland, utilizando conversor auxiliar Buck-Boost para regeneração da energia processada pelo snubber. São apresentados os estudos qualitativo e quantitativo das estruturas do inversor, snubber e conversor auxiliar, bem como o projeto final para um conjunto de especificações apresentadas. Para a realização do controle são mostrados os modelos matemáticos de todos os blocos necessários para o projeto do controlador, assim como é apresentada uma metodologia de projeto de controle baseado na resposta em freqüência. Resultados de simulação complementam o estudo e comprovam a metodologia apresentada. Para validação experimental, é desenvolvido um protótipo do inversor com snubber e conversor auxiliar, com potência de saída de 4,5kVA, freqüência de operação de 50kHz, e com capacidade de operar com potência nominal para a faixa de tensão de saída de 127V a 220V. Resultados experimentais dos circuitos de potência e controle complementam a validação deste estudo.
Fant, Sebastian. "A design of a future 10 kW converter." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11438.
Full textThis master thesis aim to design and evaluate a high power 3-phase DC/AC and AC/AC converter. The purpose is to use it for an electric motor in an aircraft possibly driving electric actuators, a propeller in an UAV or a small vehicle. Factors such as power loss and weight are of importance and will be estimated using known models supplied by various manufacturers of components. Different topologies of semiconductors suitable for this purpose are examined and presented. Extensive resources have been put to properly select the most suitable switching device according to their power loss and weight.
The need for filters and protective circuits will be estimated according to regulations of common military avionic standards and will be included in the resulting estimation along with simulations to evaluate their need and importance. Snubber circuits will be presented and their specific ability to reduce voltage transients and switching losses will be examined along with some simulations to illustrate their performance. In the final part an estimation of efficiency and weight of higher and lower power models of the same inverter has been made using the same procedure as presented in this paper. Engineering rules have been formed from these estimations to simply be able to calculate the proportions of a future converter of arbitrary rated power.
Alnasseir, Jamal. "Theoretical and experimental investigations on snubber circuits for high voltage valves of FACTS-equipment for over-voltage protection." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=98477839X.
Full textBorra, Venkata Shesha Vamsi. "Design and Modeling of High Performance LED Dimming Driver with Reduced CurrentSpikes using Turn-On Snubber across Power MOSFET." Youngstown State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1402958388.
Full textBurgardt, Ismael. "Conversor SEPIC empregando um snubber regenerativo associado a um regulador linear de corrente para acionar e controlar LEDs de potência." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1467.
Full textEste trabalho apresenta um sistema eletrônico com entrada universal utilizando um retificador SEPIC não isolado para fornecer e controlar a corrente de LEDs de potência. Um Snubber regenerativo que reduz as perdas de comutação e melhora a eficiência do sistema é proposto. Para realizar a dimerização, bem como reduzir a ondulação da corrente nos LEDs, um regulador linear de corrente é conectado na saída do conversor SEPIC. A utilização do regulador linear também permite que o conversor opere com entrada universal sem a utilização de circuitos adicionais. Para evitar perdas excessivas, o regulador é configurado para operar na região limiar da regulação. O ponto de perda mínimo do regulador é ajustado através de um circuito detector de mínimo com o sistema operando em malha fechada. As etapas de operação, as formas de onda e as principais equações do snubber regenerativo aplicado ao SEPIC são descritas no trabalho. Para verificar e validar a análise teórica são apresentados dois protótipos com potências de saída de 42 W e 145 W, variando de 15% a 100%, para o conversor operando com tensão de entrada de 90 a 240 V e alimentado 35 LEDs conectados em série.
This paper presents a universal-input AC electronic lighting system using a non-isolated SEPIC PFC rectifier to drive and control power LEDs currents. One energy regenerative snubber for reducing the converter switching losses and improve the system efficiency is proposed. The dimmable flicker-free current in the LEDs array is obtained through a linear current regulator placed in the SEPIC’s output terminals. In order to reduce the efficiency impairment, the conditions for achieving minimum energy loss in the current regulator are also detailed. Point of minimum energy loss in the linear regulator is adjusted through valley detector circuit in closed loop system operation. The operation stages as well as the theoretical waveforms and main equations at steady state of the proposed SEPIC rectifier using the regenerative snubber are described. To verify the theoretical analysis carried out, experimental results of two prototypes (42 W and 145 W) operating from 90 to 240 V and output power from 15 to 100% for 35 LEDs are also presented.
Žamberský, Jan. "Zvyšující měnič napětí." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241973.
Full textMoozhikkal, Rahul. "Design of Resonant Converters using Silicon Carbide Power." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201662.
Full textUtformningen av serie-belastade resonansomvandlare med hjälp av toppmoderna SiC högeffekttransistorernaundersöks i denna avhandlingen. SiC-enheter väljs eftersom de erbjuderlägre switch-förluster jämfört med konventionella Si-baserade enheter.En mycket detaljeradstudie om funktionen och de olika operationella tillstånden hos resonansomvandlare utförs.Avhandlingen förklarar vidare hur förmågan till högfrekvent switchning hos SiC-enheterförblir ofullständigt utnyttjad på grund av förekomsten av ströinduktanser i switch-snubberlayouten.En jämförelse av alla kommersiellt tillgängliga SiC-enheter genomförs för att hittaden mest lämpliga switchen för resonansomvandlaren. Avhandlingen utförs också en mycketdetaljerad steg-för-steg-utformning av resonansomvandlaren kretsschema och kretskortlayout.Två olika layouter föreslås och jämförs därefter utifrån deras ströinduktanser ocheffektförluster. Slutligen, baserat på experimentella resultat bekräftar avhandlingen.Lämpligheten att använda diskreta SiC-effekttransistorer istället för effektmoduler medintegrerade drivarsteg för styrelektroderna.
Sehil, Khaled. "A super-capacitor based energy storage for quick variation in stand-alone PV systems." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16222.
Full textBenda, Dušan. "Soustava DC/DC měničů pro solární panely fotovoltaické elektrárny." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377104.
Full textDundáček, Martin. "Mikroprocesorový modul řízení SS motoru se zpětnou vazbou." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217259.
Full textChen, Zheng. "Electrical Integration of SiC Power Devices for High-Power-Density Applications." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23923.
Full textPh. D.
LI, QUAN, and q. li@cqu edu au. "HIGH FREQUENCY TRANSFORMER LINKED CONVERTERS FOR PHOTOVOLTAIC APPLICATIONS." Central Queensland University. N/A, 2006. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20060830.110106.
Full textLind, Pablo. "Snubbar med klass – en semiotisk analys av bilder från Instagramkontot Snubbarinreder." Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-21451.
Full textThudén, Johansson Marie, and Hagström Susanne Reimertz. "Snubbla inte i skoltrappan : En studie om ogiltig skolfrånvaro." Thesis, Högskolan Väst, Avd för socialpedagogik och sociologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-4377.
Full textThe aim of the study is to describe how school staff and social workers identify and prevent truancy in the Swedish compulsory school. The study explores the school workers professional experiances of the underlying causes of truancy and what measures are taken in collaboration with social authorities to prevent pupils´ absence from school. The study is based on current international and national research and takes into account policy documents, legal texts and general advice issued by the Swedish National Agency for Education and the National board of Health and Welfare. The theoretical perspective used in of the analyses are the terms inclusion and exclusion. Qualitative semi-structured lifeworld interviews with five professional categories (a school head master, a councelor, a teacher and two social workers) working in school were performed. The interviews focused on causes of truancy and collaborative work involving both school professionals and social workers. The interviews were recorded and subsequently transcribed and analysed. The analysis was performed thematically, causes of truancy and collaborative work to prevent truancy. The interpretation of the data was based on consensus and differences in the responses. As can be seen from the discussion, the primary cause of truancy is related to the pupil´s home situation. Research shows that school can be a protective factor to prevent exclusion. In cases where truancy is related to the school situation it is principally a result of group pressure from other pupils. All respondents in the interviews stated that they have an awareness of where pupils with extensive absenteeism are in relation to the school´s work model to prevent truancy. Collaborative work is a success factor to reduce truancy.
Sucu, Mehmet. "Parametric average value modeling of flyback converters in ccm and dcm including parasitics and snubbers." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/38157.
Full textAmini, Akbarabadi Soroush. "Circuit averaging and numerical average value modeling of flyback converter in CCM and DCM including parasitics and snubbers." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/47052.
Full textChotpitayasunondh, Varoth. "An investigation of the antecedents and consequences of "phubbing" : how being snubbed in favour of a mobile phone permeates and affects social life." Thesis, University of Kent, 2018. https://kar.kent.ac.uk/70881/.
Full textSeveri, Matteo. "Studio sui convertitori flyback multiuscita." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/6503/.
Full textAl-fadli, Azhar, and Berggren Sara Hofberg. "“Barn som snubblar utan snubbeltråd” : En studie om hur barn i grovmotoriska svårigheter kan stöttas,stimuleras och utmanas i förskolan." Thesis, Umeå universitet, Institutionen för tillämpad utbildningsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-143586.
Full textShah, Vatsal Sonikbhai. "Optimization and Up-Gradation of 3-Phase Half-Bridge Inverter Board." Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173664.
Full textWei, Hsiao-Chi, and 魏孝麒. "Research of passive lossless snubber for." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/11026402330081629151.
Full text國立臺灣海洋大學
電機工程學系
96
With the ongoing development of power electronics technology, the inverter of IGBT are widely applied to power converting applications. It is well known that output over-voltage and energy loss during switching of inverter are the main causes for the damage of power electronic devices. To solve this problem, we first characterize the general behavior of IGBT with research, then energy loss of IGBT in both hard switching and soft switching is empirically studied. Based on these simulation results, this thesis proposes a new kind of snubber using passive lossless IGBT half-bridge inverter. Extensive simulations are carried out, and results of which verify that the snubber can suppress over-voltage and the switching loss can be effectively reduced.
Sheu, Chang-Jyi, and 許昌吉. "A Passive Lossless Snubber for ZCS Design." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/40217542549633288540.
Full textLI, TIAN-YANG, and 李天陽. "The design and application of IGBT snubber circuit." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/38468338355799620102.
Full textCHIH, LIN KUN, and 林琨智. "An Efficient Active LC Snubber for Multi-Output Converters." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/37255646858927827851.
Full text義守大學
電機工程學系
91
An efficient active LC snubber for multi-output converters is proposed in this paper. The proposed active LC snubber can be used to reset transformer and suppress switching surges. Besides, by storing surge energy in the proposed active LC snubber and then releasing it to the flyback auxiliary output, the converter can achieve high efficiency. For a forward converter with flyback auxiliary output,91.02%,the maximum output efficiency, can be achieved. For the SR forward converter with active LC snubber, 93.72%, the maximum output efficiency, can be achieved. Experimental results also show that the output efficiency of this converter with the proposed active LC snubber is higher than that of converters with an active clamp snubber.
peng, Shin wei, and 彭信瑋. "A Soft Switching Motor Drive Using an Active Snubber." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/2fs76s.
Full text國立臺北科技大學
車輛工程系所
101
This thesis proposes a pulse-width-modulation (PWM) inverter with the soft switching for the brushless DC motor (BLDCM) of the electric scooter. This motor drive could reduce switching losses, increase driving and regenerative efficiency. Moreover, this system could obtain some advantages, such as low cost and high efficiency which the capacitance is easily designed in the switched capacitor snubber. In the switching control method of this motor driver, a bidirectional conduction of inverter is used to match the relationship of the three-phase voltage of BLDCM, besides, the each internal winding of the BLDCM could be operated in a inductor. Thus a boost circuit is made up of the inductors, the MOSFET power switches, the motor electromotive force (EMF) and the input DC source. By this switching control approach, a reverse torque could be resulted in the electric brake that transfers the braking kinetic into the electric energy to the battery, thus the driving range of EV could be increased by this approach. Finally, this thesis uses a hub motor with 48V/750W to build an experimental system and some experimental results are provided to verify the correctness and feasibility of the proposed schemes.
Cheng, Yu-nan, and 鄭玉南. "Study on the Snubber Circuits for a Flyback Converter." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/qtkztw.
Full text國立臺灣科技大學
電子工程系
94
This thesis aims at the analysis of an active-clamping flyback converter. The comparisons between the active-clamping flyback converter and the conventional flyback converters adopting passive snubbers are made. The resonant tank of the active-clamping flyback converter consists of the leakage inductance of the transformer and the parasitic capacitance of the switch. The zero-voltage swtiching can be achieved by adequately design the circuit parameters. The conversion efficiency can thus be raised and the voltage spike on the switch can be reduced. Also the loss distribution is derived. An active-clamping flyback converter with an output rating of 24V/8A/200W is implemented in the lab. The experimental results are closely conformed to the theoretical analysis and the simulations.
Liu, Wen-Yuan, and 劉文淵. "Study and Implementation of LCD Snubber for a Forward Converter." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/98190222133510502958.
Full text崑山科技大學
電機工程研究所
98
The circuit design, simulation, and implementation of a forward converter with LCD snubber are presented in this thesis. The LCD snubber is composed of an inductor, a capacitor and a diode, known as passive and non-dissipative flux reset mechanism for single-ended forward converter. The capacitor of the snubber also resets the energy stored in the leakage inductor and hence, minimizes the spike voltage and reduces the EMI/RFI during the OFF period. The operational principles of the LCD snubber are analyzed in detail during steady state. According to the energy balance at resting resonant mode, a set of non-linear equation is derived and solved using the Newton-Raphson method. The magnetizing current in each breaking point is evaluated and the transformer core excited in the first and the third quadrants of the B-H plane is confirmed. The IsSpice simulation is also applied to verify the accuracy of theoretical analysis. Finally, the prototypes of a forward converter with an input of 48 V, output of 5 V/ 6 A, and switching frequency of 100 kHz has been implemented in the laboratory. In general, good agreement is observed between the theoretical and experimental results.
Yang, Zhen-Yu, and 楊鎮宇. "Multi-objective Optimization for RCD Snubber of DC-DC Converter." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83877765414325253465.
Full text國立高雄第一科技大學
系統資訊與控制研究所
100
In this paper, we propose that Multi-objective algorithm and the Taguchi method be employed in the optimal design of a DC-DC converter with an RCD snubber. The RCD snubber is usually used in flyback converter to limit the voltage spikes which are caused by leakage inductance of the transformer. The design considerations of RCD snubber are commonly two objectives: (1) minimize power loss in the snubber ; (2) minimize the voltage spikes across the transistor. But the RCD design consideration for voltage spikes suppression is usually in contradiction with power loss. So we implement the circuit by using optimal trade-off parameters, which results from comparison of pareto solution set of Multi-objective Differential Evolution (MODE), Non-Dominated sort genetic algorithm-II (NSGA-II) and Multi-objective particle swarm optimization (MOPSO) methods. Finally, the comparison of the spike voltage and power loss showed the advantages of the optimal circuit design over a non-optimal design .
Lin, Chuan-Che, and 林傳哲. "A Novel High Gain Boost Converter with Active Snubber Circuit." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3y8n6j.
Full text輔仁大學
電機工程學系碩士在職專班
106
The thesis presents a method to achieve a high voltage gain by voltage stacking technology and increasing the number of secondary winding of the coupled inductor. Then, the active snubber circuit is added to absorb the spike energy of the transformer leakage inductance for reducing the surge in the source system. Experiments and simulation results are used to verify the performance of the proposed converter operated in continuous conduction mode (CCM), discontinuous conduction mode (DCM) and boundary condition mode (BCM).
Lin, Meng-Hung, and 林孟宏. "A Soft Switching PWM Boost Converter Using an Active Snubber." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/86675320030078492722.
Full text國立海洋大學
電機工程學系
91
It has been known that normal switching power supply utilize one or more switches to transform DC from one level to another. When the switch of circuit is turned on or turned off, it has switching power losses. In order to lower volume and weight of converter its frequency needs to be raised for power density. It makes switching power loss of circuit larger than before. The efficiency of system is also reduced when the switching frequency is increased. There is a method to solve this problem. It is a soft switching technique. The paper uses soft switching technique that improves performance of the boost converter by reducing switching power loss. The theoretical results of paper is proved by simulation. The loss is reduced by an active snubber which consists of a rectifier, an inductor, a capacitor, a main switch and an auxiliary switch. The reverse recovery related of the rectifier loss is also reduced by the active snubber.
Chien, Shih Chieh, and 簡士傑. "The Integration of Semiconductor Power Switch and Built-in Snubber Circuit." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/21655893864551675630.
Full text東海大學
電機工程學系
101
The power components in the transient state of switching will cause voltage overshoot on the circuit that is particularly serious to the system safty. In this thesis, we use the C++ language to design flyback circuits. It will be easier to design, make compareisons between different designs, and analyze flyback circuits with different specifications by using a computer program. In the analysis of snubber circuit, we simplify the complicated circuit to a equivalent circuit. Then, we use four work steps to derive the equations. Finally, we use Matlab language to perform numerical analyses on the snubber circuit, more understanding about how to control V_d (MAX) was obtained. At the last, we propose the idea of snubber built-in Power IC, and using T-suprem to simulate the device process. Then use Medice to load the devices for circuit simulation, and finally we get the results as expected.
Ai, Tsu-Hua, and 艾祖華. "Integrated AC/DC Converters with Power Factor Correction and Nondissipative Snubber." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/sgt3q6.
Full text國立成功大學
電機工程學系碩博士班
90
In this dissertation, various integrated AC/DC converters with power factor correction and nondissipative snubber are discussed. A novel integrated AC/DC converter with power factor correction and line-frequency ripple suppression is proposed. And a novel nondissipative snubber integrated with AC/DC converters is also proposed. The proposed topology combines an integrated flyback and forward circuits with a post regulator. The integrated flyback and forward circuits function as two sub-converters that share the total output power. To maintain a high power factor, the flyback circuit delivers the major output power. The post-regulator with fast response to suppress line-frequency ripple controls the output voltage in constant. Therefore the proposed circuit can result in a good performance with fast dynamic response. Without the use of high voltage bulk capacitor or current sensor, the circuit features high power factor and low output line-frequency ripple in discontinuous conduction mode. The input voltage can be varied over the standard testing range (0.8-1.2 p.u.), it is suitable for home or industrial applications. To improve the efficiency of AC/DC converters, especially operating in discontinuous conduction mode, an integrated nondissipative snubber is proposed. By the use of a multi-winding transformer, the novel nondissipative snubber can be integrated with flyback or proposed AC/DC converters. No additional magnetic core, active switching and driver are needed for the proposed integrated nondissipative snubber. Therefore the proposed topology improves the efficiency without over-dimensioning of parts and with very low cost. The theoretical analysis and experimental results are presented.
Yu-HauHuang and 黃昱豪. "Forward-Flyback Converter with Snubber-feedback Network for Contactless Power Supply Application." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/14100293074439214731.
Full text國立成功大學
電機工程學系碩博士班
98
This thesis presents a proposed forward-flyback converter with the snubber-feedback network for the contactless power supply applications. In order to reduce the component count and volume, the output inductor and transformer are integrated with the proposed magnetic integration technology. Since the contactless power supply has the low conversion efficiency and low load regulation, the snubber-feedback network is applied to overcome these drawbacks. In the snubber-feedback network, an auxiliary winding of the integrated transformer is utilized as both the magnetic-loop voltage feedback and the lossless snubber inductor. A prototype circuit of the 15W forward-flyback power converter is built to verify the performances, such as load regulation, voltage stress on the power switch and efficiency, comparing with conventional one. Keyword:contactless power supply,lossless snubber,integrated transformer,output-voltage sensing circuit,forward-flyback converter
Cheng-ShingShieh and 謝正勳. "Universal-Input Single-Stage PFC Flyback LED Driver with Lossless Snubber Circuit." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/22076203742961083464.
Full text國立成功大學
電機工程學系碩博士班
99
This thesis presents a proposed universal-input single-stage PFC flyback LED driver with the lossless snubber circuit. In order to provide high power factor and low total harmonic distortion, the single-stage PFC flyback converter is employed. Moreover, in order to reduce the voltage stress on the power switch, increase the power-conversion efficiency, regulate the output voltage, the concepts of the lossless-snubber network and the isolated output-voltage-sensing network are adopted. The two windings of the lossless-snubber network and the output-voltage-sensing network are integrated as one common winding to reduce the component count Finally, a prototype circuit of the 24W universal-input single-stage PFC flyback LED driver with the lossless snubber circuit is built to verify the performances, such as voltage stress on the power switch, power conversion efficiency, power factor, total harmonic distortion, and input current harmonics.
Mo, Sheng-Zhi, and 莫勝智. "Analysis and Design of a Bridgeless Isolated SEPIC Converter with Active-Clamp Snubber." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/96649146363749344830.
Full text國立雲林科技大學
電機工程系碩士班
100
A bridgeless isolated SEPIC converter with active-clamp snubber is presented. This converter uses the bridgeless topology to reduce the rectifier diodes and improve the efficiency. The proposed converter is operated on the fixed frequency, and its input current consists of CCM and DCM parts simultaneously. During some parts of the line frequency, the converter is operated in the DCM so it can achieve the high power factor and confirm to the requirement of IEC 61000-3-2 class D. Although the converter is partly operated in the CCM will decrease the power factor, the efficiency can be improved. In addition, the active-clamp topology can achieve the characteristic of zero voltage turn-on for all switches when the converter is in the CCM operation. The main switches in the DCM operation can also achieve the function of zero current turn-on. The proposed converter is verified to be functionally worked by the experimental and simulation results based on the 150W prototype circuit and it also conforms to the requirement of IEC 61000-3-2 class D. Finally, the improved efficiency for the proposed converter can be further verified once the input current consists of the part of the CCM operation.
Lee, Hung-chi, and 李鴻麒. "The Influence of Passive Snubber Circuits on Conducted Emission of Switching Power Converters." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/77450509956025119508.
Full text國立臺灣科技大學
電子工程系
95
In this thesis, three kinds of representative snubbers are discussed, including R-C, R-C-D and L-C-D snubbers, respectively. R-C snubber, a dissipative snubber, associating with circuit leakage inductance is to form a R-L-C circuit to eliminate overvoltage and ring wave around the power device so as to suppress ring wave EMI. R-C-D snubber, a dissipative and polarized snubber, acts as a capacitor to prolong the rise time of voltage waveform around the power switch so as to suppress EMI resulted from rise time changed by voltage variation in power regulation. The last L-C-D snubber, a lossless snubber, uses inductor and resonant circuit to prolong rise time of current waveform around the power device, in which the capacitor is used to prolong rise time of the voltage waveform. It is appropriate for suppressing EMI resulted from rise time changed by voltage and current variations in power regulation. The investigation for R-C snubber is appropriate for all kinds of converters about ring wave suppression. R-C-D snubber is appropriate for all kinds of converters about voltage rise time change. L-C-D snubber is appropriate for buck and boost converters about rise time changes of current and voltage. Three kinds of snubbers are respectively applied in PFC, forward and flyback converter topologies by way of mathematics analysis and simulation for achieving a unified relationship between the mentioned snubbers, including waveform comparison and spectrum distribution. In this thesis, experiments for the three kinds of snubber circuits applied in PFC, forward and flyback converters are examined. Their performances are quite close to the theoretical predictions.
Yu, Ching-Ho, and 游景賀. "Design of Buck Type Snubber Synchronous Rectification of Full-Bridge Phase-Shift Converter." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5xgj53.
Full text國立臺灣科技大學
電子工程系
107
In the applications of full bridge, phase shift is a most popular architecture. It has an excellent performance on efficiency thanks to soft-switching, especially in high power high voltage applications. However, whether the secondary side uses synchronous rectification or non-synchronous rectification, it will produce the voltage spike on secondary rectifier switches. The voltage spike increases the voltage stress of rectifier switches. This thesis proposes a new type of buck snubber circuit not only to clamp the voltage spike but also to replace the of clamping diode on the primary side because its temperature will be high in light load and increase the power loss. The buck snubber stores the energy of voltage spike into the capacitor and transfers the energy to output which makes the spike energy recovery. By the way, the voltage stress on rectifier switches was reduced, the rectifier switches can be changed as lower voltage stress with lower turn-on resistance. The efficiency of the system will also be increased. In addition, the thesis will compare the difference of clamping point between the rectifier switch and secondary transformer. Finally, the simulation waveform and measure waveform will be used to prove the feasibility of buck snubber and its improvement of efficiency.
Wen, Hsiu-tziu, and 溫修梓. "Applications of Interleaved Forward Converter with Single-Capacitor Turn-off Snubber for Stunning Poultry." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/19317426496178333427.
Full text逢甲大學
電機工程所
94
This thesis presents a design of the poultry electric stunner. An interleaving forward converter with a single-capacitor snubber to smooth out switch turn-off transient the drain-source voltage of metal-oxide-semiconductor field effect transistor(MOSFET) switch to reduce turn-off loss is proposed to improve the conversion efficiency. In addition, the converters are operated on the boundary of continuous and discontinuous conduction modes to reduce output current ripple, as compared with the counterparts of conventional converter under full load condition, about 3% higher. As compared with the counterparts of conventional converter topologies, the proposed converters have the merits of less components count, smaller size, and they are easier to implement. The outputs of converter are direct-voltage, and alternating voltage is necessary for the poultry electrical stunner, one full-bridge inverter is added to convert dc to ac. The converters have auto-stunning mechanism, which include over-voltage, over-current and over-temperature protection circuits.
Hsu, Tsen, and 許涔. "Design of Active Snubber for Synchronous Rectification MOSFET of Full-Bridge Phase-Shifted Converter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/51543643377230836274.
Full text國立臺灣科技大學
電子工程系
105
Full-bridge phase-shift converter has the merit of zero-voltage switching (ZVS) which can reduce the switching loss and the high frequency noise interference. However, there will be voltage spike induced on the secondary side synchronous rectification MOSEFTs. This thesis presents the study upon an active snubber circuit which is designed to reduce the spike. This active snubber is compared with the well-known RC and RCD passive snubbers. The stray energy on the secondary-side is restored to the snubber capacitors, then the snubber transfers the stored energy back to the primary-side. Due to the energy retrieval, the active snubber circuit surpasses the passive counterpart on energy efficiency. Besides, the voltage stress on the synchronous rectification MOSFETs is lowered benefited from the spike reduction; the MOSFET conduction resistance i.e. the conduction loss can also be reduced. That is, the power efficiency is further improved by the application of the active snubber.
Chen, Yao-Huan, and 陳堯煥. "Optimization for RCD Snubber of Nonisolated High Step-up Boost Converter Integrated With Sepic Converter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/15938243350271124962.
Full text國立高雄應用科技大學
電機工程系博碩士班
101
In this thesis, we apply genetic algorithm and Taguchi method to develop optimal design for combining SEPIC converter and non-isolated high step-up boost converter with RCD snubber. First, genetic algorithms is used to find the parameter values of RCD snubber circuit and then Taguchi method is applied to optimize circuit implementation. In order to alleviates the peak voltage (voltage spikes) caused by switching, therefore we add the RCD snubber circuit. But as an RCD snubber circuit is the cut-off snubber passive lossy, designing the RCD snubber circuit usually needs to consider the two objectives: (1) to reduce the peak voltage on the power switch; (2) minimize power loss in the RCD snubber. After analyzing RCD design, we can know that voltage spikes suppression is usually in contradiction with power loss. Hence, we use optimization algorithms to solve the conflict between the goals and objectives of the problem and make verification. Finally, circuit of optimized design and non-optimized design will be compared and see the effect of the improvement.