The Center for Pulsed Power and Power Electronics

Texas Tech University, Lubbock, Texas

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The P3E Center, Then & Now

The Center for Pulsed Power and Power Electronicsstarted as a Plasma research group at Texas Tech University in 1966. The initial work was concerned with harmonic ion cyclotron resonances in small mirror machines, laser heating of magnetized plasmas, and pellet injection in hot dense plasmas. In 1977 a small Tokamakwas constructed and used for various wave propagation studies in the ion cyclotron range of frequencies. In the last few years the emphasis has been on power electronics, applications of plasma technology to pulsed power devices, high power microwave generation, explosive generators, and electric space propulsion engines.

Pulsed Power research at Texas Tech University began in the early 70’s with studies in high beta, controlled thermonuclear fusion. These initial investigations at Texas Tech, along with other developments in the field, established the need for a better understanding of the physical phenomena of pulsed power technology. The program is heavily interdisciplinary and presently involves faculty members from several academic departments.

Explosive pulsed power research at TTU was started in 1998. It emphasizes Magnetic Flux Compression Generators and techniques for matching their outputs to various loads. Other explosive generators, such as ferroelectric and ferromagnetic generators have also been investigated.The area of pulsed power research involves storing, shaping, transmitting, and measuring high voltage, high current pulses of electrical energy. This is of importance to many applicationareas, such as laser drivers, high power microwave generators, particle accelerators, nuclear fusion, nuclear weapons effects and lightning simulations, industrial manufacturing technology, and electromagnetic mass drivers. The voltages and currents involved may be in the MV and MA range and time scales may be as short as the sub-nanosecond regime. This calls for extremely difficult and challenging materials, shielding, and measuring techniques. High power (> 100 MW) microwave source development is an important area for military applications. Power Electronics involves high efficiency power supply designs, rotating machines, and special, high power solid state circuit designs.

4 GHz, 50 ns pulse, ~ 50 MW HPM breakdown across exit window

Air, 8 torr Ar, 16 torr

HPM

PUBLICATIONS, CONFERENCES, AND WORKSHOPS

Recent/Selected Publications

"A Bench Top Railgun With Distributed Energy Sources", IEEE Transactions on Magnetics, 43, Jan. 2007, 167 - 169 •"Cathode and Anode Optimization in a Virtual Cathode Oscillator", IEEE Trans-actions on Dielectrics and Electrical Insulation, Volume 14, Aug. 2007, 1037 -1044 •"Contributing Factors to Window Flashover under Pulsed High Power Microwave Excitation at High Altitude", IEEE Trans-actions on Dielectrics and Electrical Insulation 14, 783 - 789•"Dielectric Surface Flashover at Atmospheric Conditions with UnipolarPulsed Voltage Excitation", IEEE Transactions on Dielectrics and Electrical Insulation 14, Aug. 2007 774 - 782 •"Interface Breakdown During High-Power Microwave Transmission" IEEE Transactions on Magnetics, 43, Jan. 2007, 496 - 500•"Pulsed Gas Breakdown With High Overvoltages in Argon and Air", Pulsed Gas Breakdown With High Overvoltages in Argon and Air, Ultra-Wideband Short-Pulse Electro-magnetics 7, F. Sabbath, Ed., Springer, NY, 2007, 409-414. •"Spectral Analysis of Pulsed Volume Breakdown in SF6 at High Pressures", IEEE Transactions on Plasma Science 35, Aug. 2007, 1163 - 1169.•"Conduction and breakdown mechanisms in transformer oil", IEEE Transactions on Plasma Science, 34, April 2006, 467 - 475 •"Design and implementation of a flux compression generator nonexplosive test bed for electroexplosive fuses", Review of Scientific Instruments 77, Article 094702 (2006) (7 pages) •"High-Power Microwave Surface Flashover of a Gas-Dielectric Interface at 90-760 torr", IEEE Transactions on Plasma Science 34, Oct. 2006, 1782 - 1788 •"Monte Carlo simulation of HPM window breakdown at atmospheric conditions", Applied Physics Letters 89, 201501 (2006). •"Phenomenology of subnanosecond gas discharges at pressures below one atmosphere" IEEE Transactions on Plasma Science 34, June 2006, 927 - 936. •"Pulsed dielectric surface flashover in nitrogen at atmospheric conditions", IEEE Transactions on Dielectrics and Electrical Insulation 13, Aug. 2006, 803 - 809

•"Similarities Of Dielectric Surface Flashover at Atmospheric Conditions for Pulsed Unipolar and RF Excitation" Laser Physics in Special Issue "Plasma, Beams, and Lasers" 16, pp. 194-201, 2006. •"The Impact of Surface Conditioning and Area on the Pulsed Breakdown Strength of Water" IEEE Transactions on Plasma Science 33, Aug. 2005, 1161 - 1169 •“Fast, Transient Energy Extraction from High Frequency AC-Alternators for use in Electromagnetic Launch Applications”, IEEE Transactions on Magnetics, 41 289…293 (2005)•"DC and Pulsed Dielectric Surface Flashover at Atmospheric Pressure," IEEE Transactions on Plasma Science, 33 1149-1154, 2005.•“Design and Optimization of a Compact, Repetitive, HPM System,” Rev. Sci. Instrum. 76, 104703-1..8 (2005) •"Quantification of ohmic and intrinsic flux losses in helical flux compression Generators" IEEE Transactions on Plasma Science 32, Oct. 2004, 1902 – 1908•"Field enhanced microwave breakdown in a plasma limiter" IEEE Transactions on Plasma Science 30, Feb. 2002, 102 – 103•"Modeling of a Compulsator and RailgunSystem" IEEE Transactions on Magnetics 37 January 2001, p. 129 - 134.

Recent Book

•Explosively Driven Pulsed Power: Helical Magnetic Flux Compression Generators, Springer Verlag, July 2005.

Conferences and Workshops

Faculty members in the Pulsed Power Group are regularly involved in the organization of conferences, symposia, and workshops. Some examples are:

•First IEEE International Pulsed Power Conference (Texas Tech) 1976•Second IEEE International Pulsed Power Conference (Texas Tech) 1979•ARO Workshop on Repetitive Opening Switches (Tamarron, CO) 1981•NATO Advanced Study Institute on Electrical Breakdown and Discharges in Gases (Les Arcs, France) 1981

•ARO Workshop on Diffuse Discharge Opening Switches (Tamarron, CO) 1982

•DoD Workshop on Repetitive Spark Gap Operation (Tamarron, CO) 1983•ARO Workshop on Solid State Pulsed Power Switching (Tamarron, CO) 1983•DoD Workshop on Foreign Switch Technology (Santa Fe, NM) 1984•USAF Workshop on High-Current Opening Switches for EML Appl.cations (Tamarron, CO) 1986•Workshop on High Power Ignitrons (Lawrence Livermore National Lab.) 1988•Workshop on Transient Induced Insulator Flashover in Vacuum (LLNL) 1988•SDIO Workshop on Electrode Erosion in Electric Space Propulsion Engines (Tamarron, CO) 1989•LANL Workshop on Large Area Electron Beam Diodes (Monterey, CA) 1989•US-USSR Workshop on High Power Opening Switches (Novosibirsk, USSR)

1989•NASA Workshop on Hydrogen ArcjetSystems (Galveston, TX) 1991•IX SHCE-92 Symposium on High-Current Electronics (on the Volga River, Russia)

1992•NASA Workshop on Advanced Propulsion for Brilliant Eyes (Dallas, TX) 1994•12th Symposium on High Current Electronics (Tomsk, Russia) 2000•Institute of Advanced Technology Switch Workshop (Austin, TX) 2000•Workshop on Pulsed Power Technology for the Society of Automotive Engineers (San Diego, CA) 2000•14th IEEE International Pulsed Power Conference (Dallas, TX) 2003•Pulsed Power short course, January 6th –9th (Lubbock, TX) 2004 •2nd Japan-US Symposium on Pulsed Power and Plasma Applications (Maui, HI)

2004 •Pulsed Power short course, August 23rd -28th (Lubbock, TX) 2004•HPM symposium, August 30th-Sept 1st (Stockholm, Sweden) 2005•Power Modulator Conference, May 14th –18th (Washington, DC) 2006•3rd Japan-US Symposium on Pulsed Power and Plasma Applications (Kauai, HI)

2006•2007 IEEE Pulsed Power and Plasma Science Conference, Albuquerque, NM June 17-22, 2007

SELECTION OF MAJOR PROJECTS

Upgrading the Gigawatt Class

High Power Microwave Source

Bench Top Model of a Multi-level Cascaded AC

Inverter

Precision Dyno for Induction Motor Testing under Cyclic Loads in Oil Pumping Rigs

Arc Heated Hollow Cathode at 10 A in low pressure Argon

SELECTION OF MAJOR PROJECTS

Spark-Switched Waveguide for HPM Window Testing

Pulsed Unipolar Flashover

Dielectric Surface

Flashover at Atmospheric

Pressures

HPM window breakdown setup

HPM window breakdown

Pulsed Unipolar

Window Flashover Sequence

SELECTION OF MAJOR PROJECTS

Compact Self-Contained Prime Power / Single Use Semiconductor Switching

Adjusting the Explosive Driven Energy Storage System

Still FrameExplosively Driven

Plasma Jet Before Shot(cartridge on RHS)

Freeze FrameElectrical Connection Made Over 0.5 m Distance

SELECTION OF MAJOR PROJECTS

Non-explosive FCG simulator for switching optimization

Preparing the helical fuse Fuse in vacuum test

SELECTION OF MAJOR FACILITIES

Large High-Bay Laboratory

Off-Campus Lab for Advanced Explosives Studies and Security Sensitive Work

SELECTION OF FACILITIES/PROJECTS

Active Railgun Control High Reprate / Low Jitter Switch

Development

Modern CNC Machine shop supported by Haas Automation Inc.

PERSONNEL / RESEARCH

The Plasma, Power Electronics, and Pulsed Power Group at Texas Tech consists of 8 faculty members, with a wide range of expertise, from the departments of ECE, ME, and Physics, an average of 20 graduate students, and 8 undergraduates (assistants). The clerical and technical-support-staff com-prise one research engineer, one machinist, 4 technicians, 1 accountant, and 1 adminis-trative secretary.For further information about the plasma, power electronics, and pulsed power program at Texas Tech, contact any of the following faculty members. (Investigator and Research Area listed).

Faculty

J. C. Dickens (ECE)Associate Director(806) 742-1255E-mail: James.Dickens@ttu.eduPower Electronics, aerospace electronics,

electric space propulsion and pulsed power technology, high efficiency power processing, high power solid state lasers and power electronics, explosive pulsed power and microwave communication systems.

M. Giesselmann (ECE)(806) 742-3462E-mail: Michael.Giesselmann@ttu.eduPower Electronics, Rotating Machines,

Utility Power Systems, Gas Discharges, Electrical and Optical Diagnostics, H.V. Measuring Techniques, High Power Switching.

L. L. Hatfield (Physics)(806) 742-1256E-mail: Lynn.Hatfield@ttu.eduSurface Physics, Atomic Physics, Electrical

Space Propulsion, Dielectrics, High Voltage Insulators, High Power Microwaves.

M. Kristiansen (ECE/Physics)Director(806) 742-2224E-mail: M.Kristiansen@ttu.eduPlasma Dynamics, High Power Switching,

Gas Discharges, Electrode and Insulator Properties, High Power Microwaves, Electrical Space Propulsion, Industrial Applications, Explosive Generators.

H. Krompholz (ECE/Physics)(806) 742-1251E-mail: Hermann.Krompholz@ttu.eduPlasma Physics, Gas Discharges, Dielectric

Surface Flashover, High Speed Diagnostics, High Power Microwaves, Breakdown in Gases, Liquids, and Solids.

J. J. Mankowski (ECE)(806) 742-0526E-Mail: John.Mankowski@ttu.eduHPM sources, Pulse Forming Networks,

Liquid Breakdown, Electric Space Propulsion, Pulsed Power Technology.

A. A. Neuber (ECE)(806) 742-1250E-mail: Andreas.Neuber@ttu.eduDielectric breakdown of gases, liquids, and surfaces in vacuum and at elevated pressure (cryogenic to room temperature) under pulsed DC or HPM field, Explosive Driven Pulsed Power, High Power Microwaves, High Voltage Insulation, Pulse Generators.

Visiting & Adjunct Faculty/Researchers

C.H. Watson-Munro, Univ. of Sydney 1971.

Arndt Eberhagen, Max Planck Institut fürPlasma Physik at Garching near Munich, 1972 and 1973.

F. J. Paoloni, Univ. of Sydney 1973.

Karl I. Selin, Royal Institute of Technology, Stockholm, 1973 and 1974.

A.H. Guenther, (Adjunct Professor), Kirtland Air Force Base, Los Alamos National Laboratory, and Sandia National Laboratories, University of New Mexico 1974-2007.

Wojciech Byszewski, Polish Academy of Sciences, Warsaw, 1976 and 1979.

A. Engelhardt, (Adjunct Professor), Los Alamos National Laboratory and Enfitek, Inc., 1976-1989.

Bogdan Miedzinski, Technical University of Wroclaw, Poland, 1978 and 1979.

Alan Watson, University of Windsor, Canada, 1979, 1985, and 1986

Boy Blackwell, Univ. of Sydney 1980.

John Fletcher, School of Physical Sciences, The Flinders University of South Australia, 1982.

Jean-Pierre Boeuf, Laboratoire de Physique des Discharges, Ecole Superieured’Electricite, France, 1982.

Frank Rose, (Adjunct Professor), Naval Surface Weapons Center, Dahlgren, Virginia, 1984 and 1986.

H. Akiyama, Kumamoto University, Kumamoto, Japan, 1984 and 1986.

K. Ikuta, Nagoya Plasma Physics Laboratory, Nagoya, Japan, 1985 and 1986.

Shinsuke Watanabe, Yokohama National University, Yokohama, Japan, 1992.

W. Baker, (Adjunct Professor), Air Force Phillips Laboratory, Albuquerque, NM, 1988-1993.

Weihua Jiang, Nagaoka University of Technology, Nagaoka, Niigata, Japan, 1992, 1998-99, and 2000.

Toru Iwao, Tokyo University, Tokyo, Japan, 2000.

Thomas Müller, Deutsche Forschungsgemeinschaft, Bonn, Germany, 1993-1994.

Kevin Woolverton, Intel, 2000

Jian de Zhang, National University of Defense Technology, Changsha, Hunan, China, 2002.

Takao Namihira, Kumamoto University, Japan, 2003, 2004.

Douyan Wang, Kumamoto University, Japan 2003, 2004.

Euan Choi, Kwangwoon University, Seoul 139-701, South Korea, 2004

Han-Yong Ryu, Agency for Defense Development, South Korea, 2005

Klaus Frank, Erlangen University, Erlangen – Germany, 2007/2008

Research Projects

The following list represents some present and recent supported research programs.

Advanced Railgun Development(Air Force Office of Scientific Research/DoD MURI)

Pulsed Electrical Breakdown in SF6(Sandia National Laboratories)

High Energy Microwave Sources(FMV/Sweden)

Power Electronics(LTV & Northrop Grumman)

Nanosecond and Sub-Nanosecond Breakdown of Dielectric Media(Air Force Office of Scientific Research/DoD MURI)

High Power Microwave Breakdown ofDielectric Interfaces(Air Force Office of Scientific Research/DoD MURI)

Expendable Pulsed Power and High Power Microwave Devices(Air Force Office of Scientific Research)

Cylindrically Symmetric Vircators(Air Force Office of Scientific Research/ DoD MURI and FMV, Sweden)

Compact Pulsed Power(Air Force Office of Scientific Research/MURI, US Army TACOM)

Surface Flashover of Cryo Insulators(LANL)

Switching for Explosive Driven Pulsed Power(AFOSR)

Compact, Repetitive Marx System(FMV, Sweden)

Physics of Surface Flashover at Atmospheric Pressures(Sandia National Laboratories)

Power System Control(Northrop-Grumman)

Compact Explosive Generator System(US Army MSDC)

IED Mitigation(US Army)

THE CENTER AT A GLANCE

Equipment and Facilities

A representative sample of the equipment and facilities available for research is listed below:• Pulsed high voltage, high current diagnostic equipment, including conventional probes and optical detectors of electric fields

• Fast oscilloscopes and SCD-5000 digitizers, 80 ps rise times

• Capacitor banks• Numerous spark gaps. rail gaps, ignitrons, thyratrons, and solid state switches

• Numerous high voltage, d.c. power supplies• Various advanced field plotting and circuit analysis codes

• Marx generators (up to 2 MV)• Line pulsers and PFN’s• Laboratory power capability: 500 kVA single outlet; 1 MVA total

• Scanning electron and optical microscopes• Screen rooms and high bay areas for high voltage work

• Pulsed and CW lasers with a wide range of wavelengths and power outputs

• Optical equipment, detectors, spectrometers

• Image converter streak and framing cameras with picosecond or nanosecond temporal resolution

• High voltage, high power loads• Residual gas analyzers• Spectroradiometer• Microwave equipment• Rotating prism and mirror framing cameras• Numerous vacuum stations• Microwave interferometers• Magnetic coil systems and associated power supplies

• Various large vacuum tanks• FT IR-spectrometer• Closed cycle refrigeration system• Fluorescence detection system for CW and transient measurements

• Programmable picoammeter and voltage sources

• High pot testers• Febetron flash X-ray, 300 keV• High power microwave equipment• OMA Systems for UV-VIS-NIR spectroscopy

• Explosives chamber• Space simulation chamber

Research Areas

•Electrical space propulsion devices•Breakdown in liquids and solids•Industrial applications of pulsed power technology•Various novel switch concepts•The interaction of arc channels with electrodes and insulators•High power microwave studies•The surface physics of insulators•Solid state power electronics•Erosion resistant materials for space propulsion•Sub-nanosecond pulse gas breakdown•Magnetic flux compression generators•Explosive ferromagnetic and piezoelectric generators•Corona formation and mitigation•Circuit and rotating machine modeling•Electromagnetic Launchers

Presently, the Plasma, Power Electronics, and Pulsed Power Research Program is funded at about $3M to $4M per year.

The University

Texas Tech University, founded in 1923, is a state-supported, coeducational institution and one of the principal institutions of higher learning in the Southwest. The University consists of the School of Law, Graduate School and seven colleges: Agricultural Sciences and Natural Resources, Architecture, Arts and Sciences, Business Administration, Education, Engineering, and Human Sciences. The University offers 150 undergraduate degree programs. At the graduate level there are 100 different majors for master degrees and 50 different study areas for doctoral degrees. By the fall of 2005, enrollment at Texas Tech included 23,002 under-graduates and 4,999 graduate students. The Texas Tech University Health Sciences Center includes a School of Medicine with its Graduate School of Biomedical Sciences, a School of Nursing, and a School of Allied Health. The School of Pharmacy is located in Amarillo, Texas.The Department of Electrical and Computer

Engineering has rapidly expanded and developed its graduate programs over the past decade and currently has 22 faculty members, approximately 375 undergraduates, and 110 graduate students. Twenty-five years ago, the annual research funding was $46,000 and has increased to an average of about $5,500,000.The Department of Physics offers the M.S.

and Ph.D. degrees in Applied Physics in addition to the traditional degrees. Applied Physics majors can do research in Pulsed Power and take some courses in Electrical Engineering. The major professor can be from Physics or ECE.

Graduate Studies

Numerous grants and contracts support a variety of research that provides opportunities for graduate students to interact with prominent researchers in industry and at national laboratories. These associations are valuable to the research in progress and the long-term benefits are inestimable. Financial support ($2,000-$2,600 per month) for graduate study is for the most part obtained from Research Assistantships and Graduate Fellowships. All supported students pay in-state tuition and part of the tuition and fees are paid.The Pulsed Power and Power Electronics

Research Program at Texas Tech has generated approximately 55 theses and dissertations over the past nine years. Plasma, Power Electronics, and Pulsed Power related graduate courses offered in the EE Department include:•Electromagnetic Field Theory•Pulsed Power Technology•Gas Breakdown Phenomena•Gaseous Electronics•Pulsed Power Diagnostics •Electrical Space Propulsion•High Power Microwave Sources•Power Electronics•Machine Modeling and Control

Laboratories and Support Facilities A new EE research building, largely

devoted to pulsed power related research was completed in 1980. Today, after the addition of a high bay laboratory space in 1999, the Center for Pulsed Power and Power Electronics occupies a total floor area of over 15,000 square feet. Additional space of 12,000 square feet is used in the off-campus research building.

Computers

The computer resources available in the Pulsed Power Laboratory include several state-of-the-art MPS workstations, high-end 3-D graphics co-processors and high-speed network connections. Also available in the lab are various workstation class PC’s, color and black & white laser printers, scanners, image converter cameras, mega pixel digital cameras and MS windows domain servers with redundant hard drives and domain backup servers.

Like the hardware, an impressive list of software is available in the Center. This soft-ware includes professional versions of OrcadPSpice and Simplore (both high-end circuit solvers), Maxwell 3-D (electro and magneto static/eddy current field solver), Ansoft HFSS (3-D electro-magnetic field solver), Matlab(technical programming language), Autodyn

3-D (interactive non-linear dynamic and hydro- dynamic analysis software), LS dyna-3D (hydrodynamic code)and FEMLAB (Finite element method for solving systems of partial differential equations).

In addition to its own computing facilities the Pulsed Power Laboratory has access to the university’s high performance computing center which houses a 56 node SGI Origin Supercomputer and an impressive 3-D immersive presentation theater.

The Center for Pulsed Power and Power ElectronicsTexas Tech University, Lubbock, Texas 79409-3102, (806) 742-3468

Email: p3e@ttu.edu, Web Page: http://www.p3e.ttu.eduPlasma, Power Electronics, and Pulsed Power Research

P3E P3E CENTER FOR PULSED POWER & POWER ELECTRONICSCENTER FOR PULSED POWER & POWER ELECTRONICS