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Analysis and synthesis of an inductive storage millisecond pulse forming networkVan der Merwe, Julian Barend 12 1900 (has links)
Dissertation (PhD) -- Stellenbosch University, 2001 / ENGLISH ABSTRACT: Millisecond pulse forming networks (PFNs) as applicable to electro-thermal chemical
(ETC) loads fall into the <1 MJ energy bracket. The energy requirements of these
loads require specialised power sources involving staged energy conversion. For the
<1MJ energy bracket, capacitive storage systems are usually employed. However,
these systems exhibit low volume energy density and for volume sensitive
applications; alternatives need to be considered.
Inductive storage supplies form a sub-group of the static supplies that have
theoretically superior volume energy density characteristics.
This thesis documents the execution of a project concerned with the volumeoptimisation
of an inductive storage supply. The system is composed of a three stage
energy conversion chain. A prime power source (low power) charges an intermediate
storage (IS) which is characterised by its medium power delivery capabilities. Energy
is then transferred from the IS to the storage inductor which is characterised by its
high power delivery capabilities. When sufficiently charged, the energy is then
transferred to the load. Where pulse forming is required, the inductor storage must
necessarily be modular. Switching elements to control the energy flow are also
required.
Work performed at Soreq, Israel, is used as the starting point. A topology
variation of the XRAM topology presented by Soreq, original to this thesis, is
presented and all its functioning modes are analysed. An existing volume model is
analysed and expanded to incorporate heretofore unmodelled yet non-negligible
considerations. The volume model generalises the effect of system modularity, subsystem
technologies and allows for the incorporation of practical construction issues
into the design process. The aim is to develop a 500 kJ, 80 kA, 20 kV system with a
volume not exceeding lm3. This volume must include the IS, storage inductor and full
switch volume.
The optimisation algorithm and system topology developed in this thesis is
validated through the construction and testing of a 1.2 kA, 2.5 kV 4 module prototype.
A potential full ratings system, composed of contemporary device
technologies and exhibiting a volume of just over 0.8m3, is proposed. / AFRIKAANSE OPSOMMING: Millisekonde pulsvormingsnetwerke, soos toegepas op elektrotermies-chemiese laste,
val in die <1 MJ energievlak. Die energievereistes van hierdie tipe las vereis
gespesialiseerde kragbronne wat die gestoorde energie in verskillende stadiums aan
die las beskikbaar stel. Tans word kapasitiewe stelsels gewoonlik vir toepassings wat
minder as 1 MJ energie benodig gebruik. ‘n Nadeel van hierdie stelsels is egter hulle
relatiewe lae energiedigtheid. Vir toepassings waar lae volume van belang is, moet
altematiewe metodes ondersoek word.
Pulskragbronne wat van ‘n induktiewe energiestoor gebruik maak vorm ‘n
deel van die klas van statiese kragbronne met hoe energiedigtheid.
Hierdie tesis handel oor die optimering, in terme van volume, van ‘n
induktiewe pulskragbron. Die stelsel bestaan uit drie stadiums, wat die energie van
een vorm na ‘n ander omskakel en sodoende die vorm van die puls wat aan die las
gelewer word, beheer. A lae-drywing primere kragbron laai ‘n medium-dry wing
intermediere energiestoor. Energie word dan van die intermediere energiestoor na ‘n
hoe-drywing stoorinduktor oorgedra. Nadat die induktor volgelaai is, word die energie
aan die las oorgedra. Indien pulsvorming benodig word, kan van ‘n modulere induktor
gebruik gemaak word. Vaste-toestand skakelelemente word gebruik om die
energievloei te beheer.
Navorsing wat by Soreq, in Israel, uitgevoer is, word as die vertrekpunt vir die
studie gebruik. ‘n Verandering aan die XRAM topologie word voorgestel en die
werking daarvan word in detail geanaliseer. ‘n Bestaande volume model word
ondersoek en uitgebrei om ‘n aantal nie-weglaatbare verskynsels in aanmerking te
neem. Die nuwe volume model maak voorsiening vir modulariteit, die effek van
substelseltegnologie en ‘n aantal praktiese oorwegings wat in die ontwerp van die
stelsel ‘n rol speel. Die finale doel is om ‘n 500 kJ, 80 kA, 20 kV stelsel in ‘n volume
van 1 m3 in te pas. Hierdie volume van 1 m3 moet die intermediere energiestoor, die
stoorinduktor, asook die skakelaars, bevat.
Die optimeringsalgoritme en stelseltopologie wat ontwikkel is, word
eksperimenteel deur middel van ‘n 1.2 kA, 2.5 kV, 4 module prototipe geverifieer.
Laastens word aangetoon hoe ‘n finale stelsel, gebaseer op huidige
skakelaartegnologie, met ‘n totale volume van 0.8 m3 moontlik in die toekoms
ontwikkel kan word.
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Electromagnetic Railgun Launchers: Practical and Theoretical PerspectivesSung, Victor W. 25 October 2022 (has links)
Doctor of Philosophy / Railguns are highly complex multi-disciplinary engineering systems that use electricity to launch projectiles at very high speeds. This dissertation investigates new technologies, models, and theories necessary for the development of practical systems to bring the railgun out of the lab and into the field. The research focuses on improvements to the size, weight, performance, and efficiency of components of the railgun's power supply as well as improvements to its control. Extensive theories useful for the design and modeling of the system were developed with emphasis on scaling, efficiency, and physics. These technologies were experimentally demonstrated on a reduced scale railgun system.
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Sistema de alimentação chaveado para modulador de pulsos com linha de retardo aplicado em sistema radar = Switching mode system to supply pulse modulators based in pulse forming network applied to radar / Switching mode system to supply pulse modulators based in pulse forming network applied to radarDias, Agnaldo Vieira 21 August 2018 (has links)
Orientador: Ernesto Ruppert Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-21T00:56:13Z (GMT). No. of bitstreams: 1
Dias_AgnaldoVieira_M.pdf: 2229736 bytes, checksum: 725a7fa267bc30780c457689e4356336 (MD5)
Previous issue date: 2012 / Resumo: O estudo da utilização de conversores CC/CC isolados e elevadores de tensão para a alimentação de moduladores de pulsos é apresentado neste trabalho. Foi selecionada a topologia em ponte completa, dando-se enfoque ao problema das capacitâncias parasitas envolvidas no circuito, que aparecem de forma acentuada em transformadores elevadores de tensão e filtros indutivos de saída e são altamente indesejáveis quando se opera em regime chaveado. Essas capacitâncias são tratadas através de uma forma de amortecimento, onde a energia armazenada nas mesmas é devolvida à fonte primária ao final de cada semiciclo de chaveamento, tentando obter-se menor volume, maior rendimento e menor dissipação de calor no conversor. Além disso, um circuito de regulação de carga é utilizado para garantir uma maior estabilidade de pulso e contornar problemas típicos de moduladores de pulsos utilizados em radares, como o efeito de backswing. O modulador de pulsos utilizado como carga para esse sistema opera com uma tensão de alimentação de 1kV, frequência de repetição de pulsos (PRF) de 585Hz e consome uma potência da ordem de 2,1kW. O conversor CC/CC é alimentado por um barramento CC não regulado de 280V / Abstract: The study of high-voltage isolated DC/DC converters used to supply pulse modulators is presented on this dissertation. The Full Bridge topology was selected, focusing in problems caused by parasitic capacitances in the circuit. This characteristic, which appears sharply in high voltage transformers and in inductors of output filter, is highly undesirable when the circuit is operated in switching mode. These capacitances are handled using a soft commutation technique, where their stored energy are returned to the primary source in the end of each switching cycle, trying to get a low size, high efficiency and low heat dissipation in the converter. Moreover, a charging regulator circuit is used to ensure good pulse stability and avoid typical problems in the pulse modulators use, such as the backswing effect. The pulse modulator used as load for this converter operates with a supply voltage of 1kV, pulse repetition frequency (PRF) of 585Hz and consumes 2.1 kW. The converter input is supplied by a 280V unregulated DC bus / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica
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