Use of Diode As a Crowbar for Electromagnetic Launcher
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Microwave Tube Fault-Current Model for Design of Crowbar Protection
Microwave Tube Fault-Current Model for Design of Crowbar Protection Subhash Joshi T.G. Vinod John Member, IEEE Senior Member, IEEE Power Electronics Group Department of Electrical Engineering Centre for Development of Advanced Computing Indian Institute of Science Thiruvananthapuram-695033, India Bangalore-560012, India Email:[email protected] Email:[email protected] Abstract—Many applications that use high energy plasma are realized using Microwave tubes (MWT) that operate at peak power in the range of hundreds of MW and frequency in GHz. One failure mode of the MWT is due to the excess energy in the tube during internal arcing events. Crowbar is used to protect the MWT by diverting the energy during fault. To compute the energy released into the MWT, the dc fault current model and the MWT model are essential. An equivalent fuse wire model is utilized for the MWT for the crowbar applications. The paper proposes a model for the dc fault current, the analysis for (a) (b) which is based on Joules Integral energy concept. The model Fig. 1. Circuit network used for crowbar analysis (a) HV power supply with provides flexibility to choose a range of practically observed MWT and crowbar (b) MWT is replaced with fuse wire for wire survivability reactance to resistance ratio (X=R) of transformer and also test. allows the use of a range of dc current limiting resistances that are utilized in the High Voltage (HV) power supply circuits in Microwave applications. The non-linearity of the system due to is decided by the speed of operation of crowbar. -
Pulsed Power Engineering Materials, Components, & Devices
Pulsed Power Engineering Switching Devices June 13-17, 2011 Craig Burkhart & Mark Kemp Power Conversion Department SLAC National Accelerator Laboratory Ideal Switch • V = ∞ • I = ∞ • Closing/opening time = 0 • L = C = R = 0 • Simple to control • No delay or jitter • Lasts forever • Never fails June 13 - 17, 2011 USPAS Pulsed Power Engineering Burkhart & Kemp 2 Switches • Electromechanical • Vacuum • Gas – Spark gap – Thyratron – Ignitron – Plasma Opening • Solid state – Diodes • Diode opening switch – Thyrsitors • Electrically triggered • Optically triggered • dV/dt triggered – Transistors • IGBT • MOSFET June 13 - 17, 2011 USPAS Pulsed Power Engineering Burkhart & Kemp 3 Switches • Electromechanical – Open relay • To very high voltages, set by size of device • Commercial devices to ~0.5 MV, ~50 kA – Ross Engineering Corp. • Closing time ~10’s of ms typical – Large jitter, ~ms typical • Closure usually completed by arcing – Poor opening switch • Commonly used as engineered ground – Vacuum relay • Models that can open under load are available • Commercial devices – Maximum voltage ~0.1 MV – Maximum current ~0.1 kA – Tyco-kilovac – Gigavac June 13 - 17, 2011 USPAS Pulsed Power Engineering Burkhart & Kemp 4 Gas/Vacuum Switch Performance vs. Pressure June 13 - 17, 2011 USPAS Pulsed Power Engineering Burkhart & Kemp 5 Vacuum Tube (Switch Tube) • Space-charge limited current flow 1.5 – VON α V – High power tubes have high dissipation • Similar opening/closing characteristics • Maximum voltage ~0.15 MV • Maximum current ~0.5 kA, more typically << 100 A • HV grid drive • Decreasing availability • High Cost June 13 - 17, 2011 USPAS Pulsed Power Engineering Burkhart & Kemp 6 Spark Gaps • Closing switch • Generally inexpensive - in simplest form: two electrodes with a gap • Can operated from vacuum to high pressure (both sides of Paschen Curve) • Can use almost any gas or gas mixture as a dielectric. -
Pulsed Power Engineering Switching Devices
Pulsed Power Engineering Switching Devices January 12-16, 2009 Craig Burkhart, PhD Power Conversion Department SLAC National Accelerator Laboratory Ideal Switch •V = ∞ •I = ∞ • Closing/opening time = 0 • L = C = R = 0 • Simple to control • No delay or jitter •Lasts forever • Never fails January 12-16, 2009 USPAS Pulsed Power Engineering C Burkhart 2 Switches • Electromechanical • Vacuum •Gas – Spark gap – Thyratron – Ignitron – Plasma Opening • Solid state – Diodes • Diode opening switch – Thyrsitors • Electrically triggered • Optically triggered • dV/dt triggered – Transistors •IGBT • MOSFET January 12-16, 2009 USPAS Pulsed Power Engineering C Burkhart 3 Switches • Electromechanical – Open relay • To very high voltages, set by size of device • Commercial devices to ~0.5 MV, ~50 kA – Ross Engineering Corp. • Closing time ~10’s of ms typical – Large jitter, ~ms typical • Closure usually completed by arcing – Poor opening switch • Commonly used as engineered ground – Vacuum relay • Models that can open under load are available • Commercial devices – Maximum voltage ~0.1 MV – Maximum current ~0.1 kA – Tyco-kilovac –Gigavac January 12-16, 2009 USPAS Pulsed Power Engineering C Burkhart 4 Gas/Vacuum Switch Performance vs. Pressure January 12-16, 2009 USPAS Pulsed Power Engineering E Cook 5 Vacuum Tube (Switch Tube) • Space-charge limited current flow 1.5 –VON α V – High power tubes have high dissipation • Similar opening/closing characteristics • Maximum voltage ~0.15 MV • Maximum current ~0.5 kA, more typically << 100 A • HV grid drive • Decreasing availability • High Cost January 12-16, 2009 USPAS Pulsed Power Engineering C Burkhart 6 Spark Gaps • Closing switch • Generally inexpensive - in simplest form: two electrodes with a gap • Can operated from vacuum to high pressure (both sides of Paschen Curve) • Can use almost any gas or gas mixture as a dielectric. -
Proof-Of-Concept Experiments on a Gallium- Based Ignitron for Pulsed Power Applications
National Aeronautics and NASA/TM—2015–218202 Space Administration IS20 George C. Marshall Space Flight Center Huntsville, Alabama 35812 Proof-of-Concept Experiments on a Gallium- Based Ignitron for Pulsed Power Applications H.K. Ali, V.S. Hanson, K.A. Polzin, and J.B. Pearson Marshall Space Flight Center, Huntsville, Alabama February 2015 The NASA STI Program…in Profile Since its founding, NASA has been dedicated to the • CONFERENCE PUBLICATION. Collected advancement of aeronautics and space science. The papers from scientific and technical conferences, NASA Scientific and Technical Information (STI) symposia, seminars, or other meetings sponsored Program Office plays a key part in helping NASA or cosponsored by NASA. maintain this important role. • SPECIAL PUBLICATION. Scientific, technical, The NASA STI Program Office is operated by or historical information from NASA programs, Langley Research Center, the lead center for projects, and mission, often concerned with NASA’s scientific and technical information. The subjects having substantial public interest. NASA STI Program Office provides access to the NASA STI Database, the largest collection of • TECHNICAL TRANSLATION. aeronautical and space science STI in the world. English-language translations of foreign The Program Office is also NASA’s institutional scientific and technical material pertinent to mechanism for disseminating the results of its NASA’s mission. research and development activities. These results are published by NASA in the NASA STI Report Specialized services that complement the STI Series, which includes the following report types: Program Office’s diverse offerings include creating custom thesauri, building customized databases, • TECHNICAL PUBLICATION. Reports of organizing and publishing research results…even completed research or a major significant providing videos. -
Methods of Magnetizing Permanent Magnets EMCW Coil Winding Show 1 October-2 November 2000 Cincinnati , Ohio
Methods of Magnetizing Permanent Magnets EMCW Coil Winding Show 1 October-2 November 2000 Cincinnati , Ohio Joseph J. Stupak Jr. Oersted Technology Corp. 19480 SW Mohave Ct. Tualatin, Oregon USA 97063 Tel (503) 612-9860 fax (503) 692-3518 email [email protected] Copyright Oersted Technology 2000 Methods of Magnetizing Permanent Magnets 1. Introduction Many people find magnets to be strange, mysterious things, and I think that physicists are puzzled a good deal more by them then they like to admit. Magnets have been with us a long time, in fact from our earliest history, long before formal science was started, or the mathematics we use to describe it. We all know what magnets do. Magnets have locations on them, called poles. Poles come in two types, which we call North-seeking poles, or just North poles, and South poles. They always occur in pairs of equal strength, although they may have more than just two poles, of course. Opposite pole types attract, while poles of the same type repel each other. Poles of either type attract iron, steel, and a few other metals such as nickel. These things have been known for thousands of years. Much more recently, that is in the last two hundred years, we have found out that electricity and magnetism are related, and most of the time today we will be talking about ways to use electricity to make certain special materials, called permanent magnet materials, to be magnetic. When magnets are first produced, they are usually not magnetic at all, or possibly they are only very weakly magnetic. -
Overvoltage Crowbar Sensing Circuit MC3423
ON Semiconductor ™ ijjp MC3423 Overvoltage Crowbar Sensing Circuit OVERVOLTAGE Tliis overvoltage protection Circuit (OVP) protects sensitive SENSING CIRCUIT electronic circuitry from overvoltage transients or regulator failures when used in conjunction with an extemal “crowbar” SCR. The device senses the overvoltage condition and ąuickly “crowbars” or SEMICONDUCTOR short circuits the supply, forcing the supply into current limiting or TECHNICAL DATA opening the fuse or Circuit breaker. The protection voltage threshold is adjustable and the MC3423 can be programmed for minimum duration of overvoltage condition before tripping, thus supplying noise immunity. P1 SUFFIX The MC3423 is essentially a “two tenninal” system, therefore it PLASTIC PACKAGE can be used with either positive or negative supplies. CASE 626 D SUFFIX PLASTIC PACKAGE CASE 751 (SOP-8) MAXIMUM RATINGS Rating Symbol Value Unit PIN CONNECTIONS Differential Power Supply Voltage 40 Vdc VCC-VEE W Drive Sense Voltage (1) 6.5 Vdc 1 8 ^Sensel v cc Output Sense Voltage (2) Vsense2 6.5 Vdc Sense 1 2 7 VEE Remote Activation Input Voltage ^act 7.0 Vdc Indicator Sense 2 3 6 Output Current >o 300 mA Output Current Remote Operating Ambient Temperaturę Ta 0 to +70 °C 4 5 Rangę Source Activation Operating Junction Temperaturę Tj 125 °C (Top View) Storage Temperaturę Rangę Tstg -65 to +150 °C ORDERING INFORMATION Operating Device Temperaturę Rangę Package Simplified Application MC3423D SO-8 Ta - 0° to +70°C MC3423P1 Plastic DIP vout Current Limited + 1 r 0. V. P. 7 DC Cout MC3423 Power Supply © Semiconductor Components Industries, LLC, 2001 2690 Publication Order Number: November, 2001 - Rev. -
The Silicon Controlled Rectifier (SCR)
The silicon controlled rectifier (SCR) Shockley diodes are curious devices, but rather limited in application. Their usefulness may be expanded, however, by equipping them with another means of latching. In doing so, each becomes true amplifying devices (if only in an on/off mode), and we refer to these as silicon-controlled rectifiers, or SCRs. The progression from Shockley diode to SCR is achieved with one small addition, actually nothing more than a third wire connection to the existing PNPN structure: (Figure below) The Silicon-Controlled Rectifier (SCR) If an SCR's gate is left floating (disconnected), it behaves exactly as a Shockley diode. It may be latched by breakover voltage or by exceeding the critical rate of voltage rise between anode and cathode, just as with the Shockley diode. Dropout is accomplished by reducing current until one or both internal transistors fall into cutoff mode, also like the Shockley diode. However, because the gate terminal connects directly to the base of the lower transistor, it may be used as an alternative means to latch the SCR. By applying a small voltage between gate and cathode, the lower transistor will be forced on by the resulting base current, which will cause the upper transistor to conduct, which then supplies the lower transistor's base with current so that it no longer needs to be activated by a gate voltage. The necessary gate current to initiate latch-up, of course, will be much lower than the current through the SCR from cathode to anode, so the SCR does achieve a measure of amplification. -
H DEC 1067 /G&L
SIMPLE THYRISTOR CIRCUITS TO PULSE-FIRE IGNITRONS FOR EP-RR 16 CAPACITOR DISCHARGE H DEC 1067 /G&l C. F. VANCE March, 1967 Department of Engineering Physics Research School of Physical Sciences THE AUSTRALIAN NATIONAL UNIVERSITY ra, A.C.T., Australia. HANCOCK TJ163.A87 EP-RR16. f T.J 1 63* 1924138 . A87 F. P - R R 1 6 A.N.U. LIBRARY This book was published by ANU Press between 1965–1991. This republication is part of the digitisation project being carried out by Scholarly Information Services/Library and ANU Press. This project aims to make past scholarly works published by The Australian National University available to a global audience under its open-access policy. SIMPLE THYRISTOR CIRCUITS TO PULSE-FIRE IGNITRONS FOR CAPACITOR DISCHARGE H DEC 1967 by C. F. VANCE M arch. 1967 Publication EP-RR 16 Department of Engineering Physics Research School of Physical Sciences THE AUSTRALIAN NATIONAL UNIVERSITY C anberra, A.C.T. A ustralia S UMMARY Simple thyristor circuits have been used for firing capacitor-discharge ignitrons in a plasma physics * experiment. Experience of over 18, 000 discharges shows that the problem of semiconductor failure in an environ ment of high voltage transients can be overcome by atten tion to screening and filtering. Speed limitations of present-day thyristors are discussed and found acceptable for medium-speed plasma experiments. *(By October 1967, 48, 000 trouble-free discharges have been obtained). ii 1 . INTRODUCTION The use of thyristors in place of thyratrons has been advertised by a number of manufacturers for some time, including their use for firing ignitrons. -
Semiconductor Switches Replace Thyratrons and Ignitrons
SEMICONDUCTOR SWITCHES REPLACE THYRATRONS AND IGNITRONS A. Welleman, E. Ramezani, U. Schlapbach ABB Semiconductors AG, CH-5600 Lenzburg, Switzerland Abstract A solid state switching system is presented which is designed a high reliable, long life, low maintenance product for short repetitive and high di/dt pulses. The solid state switch uses special designed semiconductor devices with integrated fast triggering circuits which are powered by one closed loop current source power supply. Blocking voltages of over 30 kV are possible by stacking several devices in series connection. The solid state system has no environmental restrictions and can be used in any position 1) INTRODUCTION Since several years ABB is offering complete solid state switches which are based on a wide range of specific devices which are designed for non-repetitive pulsed power applications. More recently, interest has been shown in fast semiconductor switches which can be used at medium frequencies, to replace thyratrons and ignitrons because of longer life, no use of mercury and almost no maintenance. For this applications, ABB has designed a new platform technology and is using this concept in a range of different switches. These switches are so called Power Parts, as they are built up as an assembly with semiconductors, drivers, clamping, cooling, power supply and triggering, but are without cabinet or control system. 2) SEMICONDUCTOR DEVICES The evolution of silicon wafers for high di/dt application started about 1975 with the central gate SCR’s capable to handle 200 – 400 A/ms, followed later by higher interdigitated gate structures which allowed about to double these values. -
Crowbar Replacement Through Solid State Opening Switches
SOLID STATE 2MW KLYSTRON POWER CONTROL SYSTEM I. Roth, J. Casey, T. Hawkey, M. Gaudreau, M. Kempkes, Diversified Technologies, Inc. 35 Wiggins Ave. Bedford, MA 01730 USA Abstract upper part of Figure 1 shows a typical crowbar circuit, Under an SBIR effort for the DOE, Diversified which shunts energy from the load. The disadvantages of Technologies, Inc. designed, built, and installed a solid this approach are well-known. The power supply, state power control system for the Advanced Light Source capacitors, and crowbar are subjected to very high klystrons at Argonne National Laboratory (ANL). This currents and mechanical forces with every arc, and the system consists of two major elements – a 100 kV, 20 A entire power system must be reset after each arc. Using a CW solid state series switch, and a solid state voltage solid-state switch can overcome these problems. regulator for the mod-anode of the klystron. The series switch replaces the existing mercury ignitron crowbar, LOAD PROTECTION USING A SOLID- eliminating these environmentally hazardous components STATE SWITCH while providing enhanced arc protection and faster return An alternative way to protect a high voltage load is to to transmit. The mod-anode voltage regulator uses series use a solid-state switch that opens during an arc, as shown IGBTs, operating in the linear regime, to provide highly in the lower diagram of Figure 1. In a pulsed system, this rapid and accurate control of the mod-anode voltage, and switch can also serve as the pulse modulator when an therefore the output power from the klystron. -
Silicon-Controlled Rectifiers
Component Theory SCRs 1 Silicon-Controlled Rectifiers Our exploration of thyristors begins with a device called the four-layer diode, also known as a PNPN diode, or a Shockley diode after its inventor, William Shockley. This is not to be confused with a Schottky diode, that two-layer metal-semiconductor device known for its high switching speed. A crude illustration of the Shockley diode, often seen in textbooks, is a four-layer sandwich of P-N-P-N semiconductor material. 2 Silicon-Controlled Rectifiers Shockley or 4-layer diode Transistor equivalent of Shockley diode 3 Silicon-Controlled Rectifiers A silicon-controlled rectifier (or semiconductor- controlled rectifier) is a four-layer solid state device that controls current. The name "silicon controlled rectifier" or SCR is General Electric's trade name for a type of thyristor. The SCR was developed by a team of power engineers led by Gordon Hall and commercialized by Frank W. "Bill" Gutzwiller in 1957. 4 Silicon-Controlled Rectifiers Construction of SCR An SCR consists of four layers of alternating P and N type semiconductor materials. Silicon is used as the intrinsic semiconductor, to which the proper dopants are added. The junctions are either diffused or alloyed. The planar construction is used for low power SCRs (and all the junctions are diffused). The mesa type construction is used for high power SCRs. In this case, junction J2 is obtained by the diffusion method and then the outer two layers are alloyed to it, since the PNPN pellet is required to handle large currents. 5 Silicon-Controlled Rectifiers It is properly braced with tungsten plates to provide greater mechanical strength. -
Synchronous-Buck MOSFET Drivers with Deadtime
TPS2834, TPS2835 SYNCHRONOUSĆBUCK MOSFET DRIVERS WITH DEADĆTIME CONTROL SLVS223B − NOVEMBER 1999 − REVISED AUGUST 2002 D Floating Bootstrap or Ground-Reference D PACKAGE High-Side Driver (TOP VIEW) D Adaptive Dead-Time Control ENABLE 1 14 BOOT D 50-ns Max Rise/Fall Times With 3.3-nF Load IN 2 13 NC D 2.4-A Typical Output Current CROWBAR 3 12 HIGHDR NC 4 11 BOOTLO D 4.5-V to 15-V Supply Voltage Range SYNC 5 10 LOWDR D TTL-Compatible Inputs DT 6 9 NC D Internal Schottky Bootstrap Diode PGND 7 8 VCC D SYNC Control for Synchronous or Nonsynchronous Operation PWP PACKAGE (TOP VIEW) D CROWBAR for OVP, Protects Against Faulted High-Side Power FETs ENABLE 1 14 BOOT D Low Supply Current....3 mA Typical IN 2 13 NC D CROWBAR 3 12 HIGHDR Ideal for High-Current Single or Multiphase Thermal Power Supplies NC 4 Pad 11 BOOTLO SYNC 5 10 LOWDR D ° ° −40 C to 125 C Operating Virtual Junction DT 6 9 NC Temperature Range PGND 7 8 VCC D Available in SOIC and TSSOP PowerPAD Packages NC − No internal connection description The TPS2834 and TPS2835 are MOSFET drivers for synchronous-buck power stages. These devices are ideal for designing a high-performance power supply using switching controllers that do not include on-chip MOSFET drivers. The drivers are designed to deliver minimum 2-A peak currents into large capacitive loads. The high-side driver can be configured as ground-reference or as floating-bootstrap. An adaptive dead-time control circuit eliminates shoot-through currents through the main power FETs during switching transitions, and provides high efficiency for the buck regulator.