Twenty-First International Power Modulator Symposium, Conference最新文献

{"title":"A High Power Density, High Voltage Power Supply For A Pulsed Radar System","authors":"E. Bowles, S. Chapelle, G. Ferguson, D.S. Furuno, M. Marietta","doi":"10.1109/MODSYM.1994.597070","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597070","url":null,"abstract":"waveform oscillating at the L-C resonant frequency [ 11. Figure 1 shows an equivalent circuit of the resonant tank . A 37 kW, 30 kV DC-DC converter has been built and tested for a pulsed microwave radar tube application. The converter utilizes IGBT transistors in a series resonant DISCRETE DISCRETE LEAKAGE PARASITIC topology to achieve a power density of 4 kWkg pulsed, and 2.6 kWkg average. The converter operates from an input voltage of 30 kV. A resonant frequency of 70 kHz was selected to minimize transformer mass while maintaining a converter efficiency in excess of 92%. A voltage regulation of _. +0.25% has been achieved through the use of an offset comparator and a pulse modulation control system. The theory of operation, circuit topology and test results are given in this paper. TRANSFORMER TRANSFORMER","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125441775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A History Of Thyratron Lifetimes At The Stanford Linear Accelerator Center","authors":"D. Ficklin","doi":"10.1109/MODSYM.1994.597093","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597093","url":null,"abstract":"The Stanford Linear Accelerator Center (SLAC) has been in almost continuous operation since the middle 1960s, providing a remarkable opportunity to amass thyratron data. This paper reviews the history of this thyratron usage, focusing primarily on data collected during the last ten years of accelerator operation. There have been two distinct operating conditions during the history of operation at SLAC. Prior to 1985, the fundamental thyratron operating points were 46 kV anode voltage (Epy), 4.2 kA peak current, 3.8 {mu}s equivalent square pulse (esp), with a maximum repetition rate of 360 pulses per second (pps). The accelerator was upgraded during 1985, and the thyratron operating points are now 46 kV Epy, 6.3 kA, 5.4 {mu}s esp, with a maximum repetition rate of 120 pps. The SLAC high-energy physics research program requires that each of the available modulator klystron units provide a stable microwave energy source. Within these constraints, this paper explores historical thyratron lifetimes at SLAC, reviewing the available data to determine how long these thyratrons can be expected to operate before failure currently or recently used in the 243 accelerator modulators.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121168927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precision Inductance Modelling Is The Basis For Accurate PFN Simulation","authors":"L. Torok","doi":"10.1109/MODSYM.1994.597077","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597077","url":null,"abstract":"The results reported here form the basis of powerful new design tools for the modulator engineering community that enable rapid computation of the full inductance matrix of solenoidal structures with any form factor to absolute accuracy. Coaxial, single layer solenoids are modelled from the physical parameters of mean winding diameter, bare wire diameter, coil length, pitch and number of turns using the Round Wire Model (RWM). The RWM is based on Maxwell’s quasi-stationary equation for mutual inductance in elliptic integrals of the first and second kind, and Rayleigh-Niven’s formula for self-inductance. The RWM is assembled in the form of a Toeplitz matrix. This structure permits ready determination of the boundaries required to compute the mutual inductances for tapped and digitated coil sections. The RWM is a fast computing absolute formula supplanting the need for Rosa’s correction as well as the idealised Current Sheet Model (CSM) of Lorenz. The algorithms analytically define all elements of the inductance matrix. The Current Sheet Model The CSM assumes that, the solenoid is wound from an infinitely thin strip of conductor, the breadth of the conducting strip is equal to the winding pitch, the tums have infinitesimal separation between them, the diameter of the conducting strip equals the mean diameter of a similar winding made with real wire. S e e figure 1. Although the CSM seems to be somewhat idealized, it is sufficiently accurate in most practical applications. Lorenz’s Eauation in Elliptic Integrals The CSM inductance is evaluated using Lorenz’s formula: where r(k; I) and E(k; 3) are the complete elliptic integrals of the fiist and second‘ kind.’ variables are illustrated in figure 1. The parameter k and the other","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127700583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design Of Reliable High Voltage Avalanche Transistor Pulsers","authors":"E. Fulkerson, R. Booth","doi":"10.1109/MODSYM.1994.597053","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597053","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126851943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MOS-gated Thyristors (MCTs) For High Power Switching","authors":"S. Bayne, W. Portnoy, G.J. Rohwein, J. Hudgins","doi":"10.1109/MODSYM.1994.597046","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597046","url":null,"abstract":"Although power semiconductor switches have been used extensively in many power electronics applications, their utilization in pulse power circuitry has remained low. The principle reason has probably been the perception that short pulse operation, particularly under fast turn-on stress, either was not possible at all, or when possible, led to early failure. However, it has recently been shown (1, 2, 3, 4, 5, 6) that high peak currents and fast risetimes can be simultaneously obtained for short pulses in discrete semiconductor thyristors, and that the use of single elements in pulse power circuits is feasible for repetitive peak currents up to 10 KA and di/dt values in excess of 20 W p s (6). The advantage of thyristors over other semiconductor types of semiconductor switches is their high blocking voltage and very high steady-state current carrying capacity. There are, however, several types of thyristors, and both the gate turn-off thyristor (GTO) and the MOS-gated thyristor (MCT) are possible competitors; MCTs have, in fact, been proposed as a superior alternative to conventionally gated SCRs for pulsed power. Although some comparisons between conventional thyristors and GTOs have been made (5), there have been none with MCTs. This work was done to determine the behavior of MCTs as closing switches (capacitor discharge) under high current, short pulse, and repetitive operation for comparison with other types of thyristors.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121388105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-repetition Rate, High-voltage Pulser For Multi-atmosphere C0/sub 2/ Laser","authors":"J. J. Nel, D. Mulder, H. V. von Bergmann, P. Swart, H. Tromp","doi":"10.1109/MODSYM.1994.597043","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597043","url":null,"abstract":"A high-repetition rate, high-voltage excitation system has been built for a multi-atmosphere CO;! laser, employcd in the Molecular Laser Isotope Separation (MLIS) process. The system has been designed to the demanding industrial reliability standards required by the MLIS process and will be capable of driving the-high pressure CO;! laser at repetition rates of up to 2 kHz. The excitation system consists of a modular, microprocessor controlled pulse power supply and a thyratron switchcd LC inversion laser pulser eniploying a single stage of magnetic pulse compression. , The pulse power supply chargcs a single stage LC inversion pulser to energy levels of 60 J in 150 psec at 70 kV peak voltage. Each module can individually generate pulses at a repetition rate of 250 Hz and 8 modules are time multiplexed to achieve an overall repetition rate of 2 kHz. The pulser supplies voltage pulses of 120 kV with risc timcs of 120 ns to the laser. Application background Molecular laser isotope separation (MLIS) requires for its initial selective excitation step a continuously tuneable laser source with a wavelength in the 16 pm range'. High repetition rate, pulsed CO;! lasers emitting in the 10 pm range can be employed as primary laser sources for this step and the requircd 16 pm radiation is then crcated via a four-wave mixing process in a multipass Raman cell. Tuneability of a CO;! laser can be achieved by utilising the pressure broadening of the CO;! emission lines at high gas pressurcs. Continuous tuneability of the laser requires operating pressures of 8-10 bar. Furthermore, the MLIS process demands laser pulse repctition rates in excess of 1 kHz. Excitation system parameters There are several problcms associatcd with higlipressure, high-repetition rate opcration of CO2 lasers. High excitation voltagcs of 10-14 kVcnr'bar' and voltage rise times in the order of 100 ns are necessary for the creation of stable, arc-frce discharges. The generation of homogeneous glow discharges becomes generally more diflicult at pressures in excess of 1 bar, 63 demanding eficient pre-ionization techniques. Furthermore, specific discharge input energies required for the generation of suflicicnt laser gain, scale directly with the operating pressure and typically 100-150 J litre'bar' have to be supplied. At high repetition rates a fast transverse gas flow has to be provided to replace the gas in the discharge volume between successive laser excitations and performance of the lasers can be severely limited by acoustically initiated discharge instabilities. Optical performance and required excitation parameters of the laser were established on an experimental, low repetition rate device. In order to keep excitation parameters of the laser at a manageable level, a small electrode separation of 10 mm arid an active discharge volume of 50 cm3 were selected. Experiments indicated that an electrode breakdown voltage of 100 kV was necessary to generate stable discharges and an input ene","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127800175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface Modification Of Polymers Using Short Pulse Flashlamps","authors":"D. S. Dunn, A. Ouderkirk","doi":"10.1109/MODSYM.1994.597101","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597101","url":null,"abstract":"a The use of excimer lasers to produce surface modification of polymers has been known for some time. this area has been directed, however, toward the use of laser energy densities high enough to ablate material from the polymer surface for etching or texturing applications.2-6 These processes are generally quite costly to perform and usually do not find application where it is desired to modify large surface areas at high process speeds In this paper we describe our work using excimer lasers and short pulse flashlamps to disorder the surface region of oriented, semicrystalline polymers without material ablation from the polymer surface. This lower energy surface modification phenomenon is potentially much less costly than ablation and provides an industrially useh1 process for controlling the surface properties of polymers. Most of the work in","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133682316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Command Resonant Charging System For A 350 kW Average Power Line Type Modulator","authors":"R. Ness, B. L. Thomas, G. Schofield","doi":"10.1109/MODSYM.1994.597068","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597068","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134235124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fiber-optic Control Of Current Filaments In High Gain Photoconductive Semiconductor Switches","authors":"F. Zutavern, G. Loubriel, W. Helgeson, M. O’Malley, R. R. Gallegos, A. Baca, T. A. Plut, H. Hjalmarson","doi":"10.1109/MODSYM.1994.597057","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597057","url":null,"abstract":"The discovery of current filaments in GaAs photoconductive semiconductor switches (PCSS) raised concerns about the location and density of the current distribution during high gain switching. This paper describes experiments using fiber-optic coupled laser diode arrays (LDA) to control the location and number of current filaments in GaAs PCSS. Infrared (IR) images of the recombination radiation, that is emitted from the surface of the PCSS, show precisely where the current is concentrated. These were recorded as the fiber-optic configuration and switch test parameters were varied. Up to twenty individually-coupled laser diodes and fibers were used to initiate multiple, simultaneous filaments. Fibers were configured in a row both parallel and perpendicular to the direction of current. Two types of experiments were performed: high current and high voltage. System impedances of 0.25 {Omega} and 50 {Omega} were used with switch currents up to 5.2 kA and initial charging voltages up to 100 kV, respectively. Switch sizes were 1{times}5 mm{sup 2} and 15{times}38 mm{sup 2} (parallel {times} perpendicular to the current). With the 0.25 {Omega} system charged to 4 kV (40 kV/cm across the PCSS), individual filaments were triggered with 150 nJ of optical trigger energy. In this case, filaments were triggered atmore » both ends near the contacts with pairs of 250 {mu}m fibers, each of which delivered 75 nJ in 140 ps. The use of multiple fiber pairs to distribute the current more uniformly across the switch improved switch performance. It allowed higher total currents to be switched with narrower switches. With the 50 {Omega} system charged to 100 kV (67 kV/cm across the PCSS), individual filaments were triggered with as little as 90 nJ of optical trigger energy. The trigger pulse was delivered in 2 ns through one fiber which was 400 {mu}m in diameter.« less","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114185051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 350 kW Average Power Thyratron Switched Line Type Modulator","authors":"R. Ness, B. L. Thomas, G. Schofield","doi":"10.1109/MODSYM.1994.597035","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597035","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123889297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}