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Sample records for high power short

  1. High Average Power, High Energy Short Pulse Fiber Laser System

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  2. Analysis of High Power IGBT Short Circuit Failures

    Pappas, G.

    2005-02-11

    The Next Linear Collider (NLC) accelerator proposal at SLAC requires a highly efficient and reliable, low cost, pulsed-power modulator to drive the klystrons. A solid-state induction modulator has been developed at SLAC to power the klystrons; this modulator uses commercial high voltage and high current Insulated Gate Bipolar Transistor (IGBT) modules. Testing of these IGBT modules under pulsed conditions was very successful; however, the IGBTs failed when tests were performed into a low inductance short circuit. The internal electrical connections of a commercial IGBT module have been analyzed to extract self and mutual partial inductances for the main current paths as well as for the gate structure. The IGBT module, together with the partial inductances, has been modeled using PSpice. Predictions for electrical paths that carry the highest current correlate with the sites of failed die under short circuit tests. A similar analysis has been carried out for a SLAC proposal for an IGBT module layout. This paper discusses the mathematical model of the IGBT module geometry and presents simulation results.

  3. Research with high-power short-wavelength lasers

    Holzrichter, J.F.; Campbell, E.M.; Lindl, J.D.; Storm, E.

    1985-01-01

    Three important high-temperature, high-density experiments were conducted recently using the 10-TW, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. These experiments demonstrated successful solutions to problems that arose during previous experiments with long wavelength lasers (lambda greater than or equal to 1μm) in which inertial confinement fusion (ICF), x-ray laser, and other high-temperature physics concepts were being tested. The demonstrations were: (1) large-scale plasmas (typical dimensions of up to 1000 laser wavelengths) were produced in which potentially deleterious laser-plasma instabilities were collisionally damped. (2) Deuterium-tritium fuel was imploded to a density of 20 g/cm 3 and a pressure of 10 10 atm. (3) A 700-fold amplification of soft x rays by stimulated emission at 206 and 209 A (62 eV) from Se +24 ions was observed in a laser-generated plasma. Isoelectronic scaling to 155 A (87 eV) in Y +29 was also demonstrated

  4. Transient analysis of the output short-circuit fault of high power and high voltage DC power supply

    Yang Zhigang; Zhang Jian; Huang Yiyun; Hao Xu; Sun Haozhang; Guo Fei

    2014-01-01

    The transient conditions of output short-circuit fault of high voltage DC power supply was introduced, and the energy of power supply injecting into klystron during the protection process of three-electrode gas switch were analyzed and calculated in detail when klystron load happening electrode arc faults. The results of calculation and simulation are consistent with the results of the experiment. When the output short-circuit fault of high voltage power supply occurs, switch can be shut off in the microsecond, and the short circuit current can be controlled in 200 A. It has verified the rapidity and reliability of the three-electrode gas switch protection, and it has engineering application value. (authors)

  5. Short pulse mid-infrared amplifier for high average power

    Botha, LR

    2006-09-01

    Full Text Available High pressure CO2 lasers are good candidates for amplifying picosecond mid infrared pulses. High pressure CO2 lasers are notorious for being unreliable and difficult to operate. In this paper a high pressure CO2 laser is presented based on well...

  6. Stochastic Short-term High-resolution Prediction of Solar Irradiance and Photovoltaic Power Output

    Melin, Alexander M. [ORNL; Olama, Mohammed M. [ORNL; Dong, Jin [ORNL; Djouadi, Seddik M. [ORNL; Zhang, Yichen [University of Tennessee, Knoxville (UTK), Department of Electrical Engineering and Computer Science

    2017-09-01

    The increased penetration of solar photovoltaic (PV) energy sources into electric grids has increased the need for accurate modeling and prediction of solar irradiance and power production. Existing modeling and prediction techniques focus on long-term low-resolution prediction over minutes to years. This paper examines the stochastic modeling and short-term high-resolution prediction of solar irradiance and PV power output. We propose a stochastic state-space model to characterize the behaviors of solar irradiance and PV power output. This prediction model is suitable for the development of optimal power controllers for PV sources. A filter-based expectation-maximization and Kalman filtering mechanism is employed to estimate the parameters and states in the state-space model. The mechanism results in a finite dimensional filter which only uses the first and second order statistics. The structure of the scheme contributes to a direct prediction of the solar irradiance and PV power output without any linearization process or simplifying assumptions of the signal’s model. This enables the system to accurately predict small as well as large fluctuations of the solar signals. The mechanism is recursive allowing the solar irradiance and PV power to be predicted online from measurements. The mechanism is tested using solar irradiance and PV power measurement data collected locally in our lab.

  7. An ultra short pulse reconstruction software applied to the GEMINI high power laser system

    Galletti, Mario, E-mail: mario.gall22@gmail.com [INFN – LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Galimberti, Marco [Central Laser Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); Hooker, Chris [Central Laser Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); University of Oxford, Oxford (United Kingdom); Chekhlov, Oleg; Tang, Yunxin [Central Laser Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); Bisesto, Fabrizio Giuseppe [INFN – LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Curcio, Alessandro [INFN – LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Sapienza – University of Rome, P.le Aldo Moro, 2, 00185 Rome (Italy); Anania, Maria Pia [INFN – LNF, Via Enrico Fermi 40, 00044 Frascati (Italy); Giulietti, Danilo [Physics Department of the University and INFN, Pisa (Italy)

    2016-09-01

    The GRENOUILLE traces of Gemini pulses (15 J, 30 fs, PW, shot per 20 s) were acquired in the Gemini Target Area PetaWatt at the Central Laser Facility (CLF), Rutherford Appleton Laboratory (RAL). A comparison between the characterizations of the laser pulse parameters made using two different types of algorithms: Video Frog and GRenouille/FrOG (GROG), was made. The temporal and spectral parameters came out to be in great agreement for the two kinds of algorithms. In this experimental campaign it has been showed how GROG, the developed algorithm, works as well as VideoFrog algorithm with the PetaWatt pulse class. - Highlights: • Integration of the diagnostic tool on high power laser. • Validation of the GROG algorithm in comparison to a well-known commercial available software. • Complete characterization of the GEMINI ultra-short high power laser pulse.

  8. Advances in High Power Calorimetric Matched Loads for Short Pulses and CW Gyrotrons

    Bin, W.M.; Bruschi, A.; Cirant, S.; Gandini, F.; Granucci, G.; Mellera, V.; Muzzini, V.; Nardone, A.; Sozzi, C.; Spinicchia, N.

    2006-01-01

    The development of high power gyrotrons for plasma physics research needs proper matched and calorimetric loads able to absorb and measure the power, which nowadays is foreseen to be as high as 2 MW during CW operations. To this end IFP/CNR has developed a family of matched loads useful in the mm-wave frequency band for applications ranging from a few ms to CW in pulse length. The different loads in the family, made of an integrating sphere with a partially reflecting coating on the inner wall, are characterized by having the same absorbing geometry for the incoming beam and a different heat removal system for the specific application. Some important advances have been recently achieved from the point of view of the uniformity of power distribution on the absorbing wall and of the load construction. With high precision achieved in the coating thickness a better control of the heating power distribution is possible by proper shaping of the local reflectivity, in addition to the shaping of the mirror dispersing the input beam. A more sophisticated model describing the power distribution has been developed, taking into account a variable thickness of the absorbing coating, the proper shape of the spreading mirror, the frequency of the incoming radiation and the shape of the input beam. Lower coating thickness is shown to be preferable, at equal local reflectivity, from the point of view of a lower peak temperature and thermal stress. The paper describes a load with variable coating thickness along the meridian of the sphere, showing a uniform power deposition on the inner walls. The cooling pipe is completely electroformed on the spherical copper shell, ensuring the maintenance of the correct curvature of the inner surface and a fast heat conduction from the absorbing coating to the water through the thin copper body. For CW use all heated parts of the load must be cooled and this is achieved by 16 electroformed spiral channels. Both short pulse loads (0.1-1 s) and

  9. Towards shorter wavelength x-ray lasers using a high power, short pulse pump laser

    Tighe, W.; Krushelnick, K.; Valeo, E.; Suckewer, S.

    1991-05-01

    A near-terawatt, KrF* laser system, focussable to power densities >10 18 W/cm 2 has been constructed for use as a pump laser in various schemes aimed at the development of x-ray lasing below 5nm. The laser system along with output characteristics such as the pulse duration, the focal spot size, and the percentage of amplified spontaneous emission (ASE) emitted along with the laser pulse will be presented. Schemes intended to lead to shorter wavelength x-ray emission will be described. The resultant requirements on the pump laser characteristics and the target design will be outlined. Results from recent solid target experiments and two-laser experiments, showing the interaction of a high-power, short pulse laser with a preformed plasma, will be presented. 13 refs., 5 figs

  10. High power, short pulses ultraviolet laser for the development of a new x-ray laser

    Meixler, L.; Nam, C.H.; Robinson, J.; Tighe, W.; Krushelnick, K.; Suckewer, S.; Goldhar, J.; Seely, J.; Feldman, U.

    1989-04-01

    A high power, short pulse ultraviolet laser system (Powerful Picosecond-Laser) has been developed at the Princeton Plasma Physics Laboratory (PPPL) as part of experiments designed to generate shorter wavelength x-ray lasers. With the addition of pulse compression and a final KrF amplifier the laser output is expected to have reached 1/3-1/2 TW (10 12 watts) levels. The laser system, particularly the final amplifier, is described along with some initial soft x-ray spectra from laser-target experiments. The front end of the PP-Laser provides an output of 20--30 GW (10 9 watts) and can be focussed to intensities of /approximately/10 16 W/cm 2 . Experiments using this output to examine the effects of a prepulse on laser-target interaction are described. 19 refs., 14 figs

  11. Generating high-power short terahertz electromagnetic pulses with a multifoil radiator.

    Vinokurov, Nikolay A; Jeong, Young Uk

    2013-02-08

    We describe a multifoil cone radiator capable of generating high-field short terahertz pulses using short electron bunches. Round flat conducting foil plates with successively decreasing radii are stacked, forming a truncated cone with the z axis. The gaps between the foil plates are equal and filled with some dielectric (or vacuum). A short relativistic electron bunch propagates along the z axis. At sufficiently high particle energy, the energy losses and multiple scattering do not change the bunch shape significantly. When passing by each gap between the foil plates, the electron bunch emits some energy into the gap. Then, the radiation pulses propagate radially outward. For transverse electromagnetic waves with a longitudinal (along the z axis) electric field and an azimuthal magnetic field, there is no dispersion in these radial lines; therefore, the radiation pulses conserve their shapes (time dependence). At the outer surface of the cone, we have synchronous circular radiators. Their radiation field forms a conical wave. Ultrashort terahertz pulses with gigawatt-level peak power can be generated with this device.

  12. European Short-term Electricity Market Designs under High Penetration of Wind Power

    Chaves Avila, J.P.

    2014-01-01

    The EU has ambitious policies for decarbonization of the electricity sector. Due to recent technological developments, wind power already represents a significant share of the generation mix in some European countries. As a result, short-term electricity markets and balancing arrangements must be

  13. Cold cathode electron guns in the LASL high power short-pulse CO2 laser program

    Singer, S.; Ladish, J.S.; Nutter, M.J.

    1975-01-01

    The Electron Beam Controlled Discharge CO 2 Laser is now firmly established as the only high power short pulse laser amplifier that has been demonstrated to have scaling capabilities to large apertures and energies much greater than 100 J. These devices require a beam of energetic electrons to control the gas discharge that produces the required population inversion. Until recently, the electron source was usually a thermionic emitter, even for rather large lasers, whose heater requirements dwarfed the pulsed energies associated with the transient operation of the laser. With the advent of reliable cold-cathode electron guns, the operation of these lasers has been greatly simplified. At LASL, there are four electron beam controlled laser systems which are in operation, under construction, or in design: the 1 kJ system, now operational; the 2.5 kJ system; the 10 kJ system; and the 100 kJ system. Only the first uses thermionic-emitter electron guns; the remainder use or will use cold cathode sources. The operation of the 200 x 35 cm 2 two sided cold cathode electron gun used in the 2.5 kJ laser system and to be used in the 10 kJ laser is described

  14. Electro-thermal modeling of high power IGBT module short-circuits with experimental validation

    Wu, Rui; Iannuzzo, Francesco; Wang, Huai

    2015-01-01

    A novel Insulated Gate Bipolar Transistor (IGBT) electro-thermal modeling approach involving PSpice and ANSYS/Icepak with both high accuracy and simulation speed has been presented to study short-circuit of a 1.7 kV/1 kA commercial IGBT module. The approach successfully predicts the current...

  15. Highly excited bound-state resonances of short-range inverse power-law potentials

    Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

    2017-11-15

    We study analytically the radial Schroedinger equation with long-range attractive potentials whose asymptotic behaviors are dominated by inverse power-law tails of the form V(r) = -β{sub n}r{sup -n} with n > 2. In particular, assuming that the effective radial potential is characterized by a short-range infinitely repulsive core of radius R, we derive a compact analytical formula for the threshold energy E{sub l}{sup max} = E{sub l}{sup max}(n, β{sub n}, R), which characterizes the most weakly bound-state resonance (the most excited energy level) of the quantum system. (orig.)

  16. Three-Phase Short-Circuit Current Calculation of Power Systems with High Penetration of VSC-Based Renewable Energy

    Niancheng Zhou

    2018-03-01

    Full Text Available Short-circuit current level of power grid will be increased with high penetration of VSC-based renewable energy, and a strong coupling between transient fault process and control strategy will change the fault features. The full current expression of VSC-based renewable energy was obtained according to transient characteristics of short-circuit current. Furtherly, by analyzing the closed-loop transfer function model of controller and current source characteristics presented in steady state during a fault, equivalent circuits of VSC-based renewable energy of fault transient state and steady state were proposed, respectively. Then the correctness of the theory was verified by experimental tests. In addition, for power grid with VSC-based renewable energy, superposition theorem was used to calculate AC component and DC component of short-circuit current, respectively, then the peak value of short-circuit current was evaluated effectively. The calculated results could be used for grid planning and design, short-circuit current management as well as adjustment of relay protection. Based on comparing calculation and simulation results of 6-node 500 kV Huainan power grid and 35-node 220 kV Huaisu power grid, the effectiveness of the proposed method was verified.

  17. Short-Term and Medium-Term Reliability Evaluation for Power Systems With High Penetration of Wind Power

    Ding, Yi; Singh, Chanan; Goel, Lalit

    2014-01-01

    reliability evaluation techniques for power systems are well developed. These techniques are more focused on steady-state (time-independent) reliability evaluation and have been successfully applied in power system planning and expansion. In the operational phase, however, they may be too rough......The expanding share of the fluctuating and less predictable wind power generation can introduce complexities in power system reliability evaluation and management. This entails a need for the system operator to assess the system status more accurately for securing real-time balancing. The existing...... an approximation of the time-varying behavior of power systems with high penetration of wind power. This paper proposes a time-varying reliability assessment technique. Time-varying reliability models for wind farms, conventional generating units, and rapid start-up generating units are developed and represented...

  18. Forward voltage short-pulse technique for measuring high power laser array junction temperature

    Meadows, Byron L. (Inventor); Amzajerdian, Frazin (Inventor); Barnes, Bruce W. (Inventor); Baker, Nathaniel R. (Inventor)

    2012-01-01

    The present invention relates to a method of measuring the temperature of the P-N junction within the light-emitting region of a quasi-continuous-wave or pulsed semiconductor laser diode device. A series of relatively short and low current monitor pulses are applied to the laser diode in the period between the main drive current pulses necessary to cause the semiconductor to lase. At the sufficiently low current level of the monitor pulses, the laser diode device does not lase and behaves similar to an electronic diode. The voltage across the laser diode resulting from each of these low current monitor pulses is measured with a high degree of precision. The junction temperature is then determined from the measured junction voltage using their known linear relationship.

  19. A high-average power tapered FEL amplifier at submillimeter frequencies using sheet electron beams and short-period wigglers

    Bidwell, S.W.; Radack, D.J.; Antonsen, T.M. Jr.; Booske, J.H.; Carmel, Y.; Destler, W.W.; Granatstein, V.L.; Levush, B.; Latham, P.E.; Zhang, Z.X.

    1990-01-01

    A high-average-power FEL amplifier operating at submillimeter frequencies is under development at the University of Maryland. Program goals are to produce a CW, ∼1 MW, FEL amplifier source at frequencies between 280 GHz and 560 GHz. To this end, a high-gain, high-efficiency, tapered FEL amplifier using a sheet electron beam and a short-period (superconducting) wiggler has been chosen. Development of this amplifier is progressing in three stages: (1) beam propagation through a long length (∼1 m) of short period (λ ω = 1 cm) wiggler, (2) demonstration of a proof-of-principle amplifier experiment at 98 GHz, and (3) designs of a superconducting tapered FEL amplifier meeting the ultimate design goal specifications. 17 refs., 1 fig., 1 tab

  20. Short-term high intensity plyometric training program improves strength, power and agility in male soccer players.

    Váczi, Márk; Tollár, József; Meszler, Balázs; Juhász, Ivett; Karsai, István

    2013-03-01

    The aim of the present study was to investigate the effects of a short-term in-season plyometric training program on power, agility and knee extensor strength. Male soccer players from a third league team were assigned into an experimental and a control group. The experimental group, beside its regular soccer training sessions, performed a periodized plyometric training program for six weeks. The program included two training sessions per week, and maximal intensity unilateral and bilateral plyometric exercises (total of 40 - 100 foot contacts/session) were executed. Controls participated only in the same soccer training routine, and did not perform plyometrics. Depth vertical jump height, agility (Illinois Agility Test, T Agility Test) and maximal voluntary isometric torque in knee extensors using Multicont II dynamometer were evaluated before and after the experiment. In the experimental group small but significant improvements were found in both agility tests, while depth jump height and isometric torque increments were greater. The control group did not improve in any of the measures. Results of the study indicate that plyometric training consisting of high impact unilateral and bilateral exercises induced remarkable improvements in lower extremity power and maximal knee extensor strength, and smaller improvements in soccer-specific agility. Therefore, it is concluded that short-term plyometric training should be incorporated in the in-season preparation of lower level players to improve specific performance in soccer.

  1. Short-Term High Intensity Plyometric Training Program Improves Strength, Power and Agility in Male Soccer Players

    Váczi, Márk; Tollár, József; Meszler, Balázs; Juhász, Ivett; Karsai, István

    2013-01-01

    The aim of the present study was to investigate the effects of a short-term in-season plyometric training program on power, agility and knee extensor strength. Male soccer players from a third league team were assigned into an experimental and a control group. The experimental group, beside its regular soccer training sessions, performed a periodized plyometric training program for six weeks. The program included two training sessions per week, and maximal intensity unilateral and bilateral plyometric exercises (total of 40 – 100 foot contacts/session) were executed. Controls participated only in the same soccer training routine, and did not perform plyometrics. Depth vertical jump height, agility (Illinois Agility Test, T Agility Test) and maximal voluntary isometric torque in knee extensors using Multicont II dynamometer were evaluated before and after the experiment. In the experimental group small but significant improvements were found in both agility tests, while depth jump height and isometric torque increments were greater. The control group did not improve in any of the measures. Results of the study indicate that plyometric training consisting of high impact unilateral and bilateral exercises induced remarkable improvements in lower extremity power and maximal knee extensor strength, and smaller improvements in soccer-specific agility. Therefore, it is concluded that short-term plyometric training should be incorporated in the in-season preparation of lower level players to improve specific performance in soccer. PMID:23717351

  2. Short-pulse optical parametric chirped-pulse amplification for the generation of high-power few-cycle pulses

    Major, Zs.; Osterhoff, J.; Hoerlein, R.; Karsch, S.; Fuoloep, J.A.; Krausz, F.; Ludwig-Maximilians Universitaet, Muenchen

    2006-01-01

    Complete test of publication follows. In the quest for a way to generate ultrashort, high-power, few-cycle laser pulses the discovery of optical parametric amplification (OPA) has opened up to the path towards a completely new regime, well beyond that of conventional laser amplification technology. The main advantage of this parametric amplification process is that it allows for an extremely broad amplification bandwidth compared to any known laser amplifier medium. When combined with the chirped-pulse amplification (CPA) principle (i.e. OPCPA), on one hand pulses of just 10 fs duration and 8 mJ pulse energy have been demonstrated. On the other hand, pulse energies of up to 30 J were also achieved on a different OPCPA system; the pulse duration in this case, however, was 100 fs. In order to combine ultrashort pulse durations (i.e. pulses in the few-cycle regime) with high pulse energies (i.e. in the Joule range) we propose tu pump on OPCPA chain with TW-scale short pulses (100 fs - 1 ps instead of > 100 ps of previous OPCPA systems) delivered by a conventional CPA system. This approach inherently improves the conditions for generating high-power ultrashort pulses using OPCPA in the following ways. Firstly, the short pump pulse duration reduces the necessary stretching factor for the seed pulse, thereby increasing stretching and compression fidelity. Secondly, also due to the shortened pump pulse duration, a much higher contrast is achieved. Finally, the significantly increased pump power makes the use of thinner OPCPA crystals possible, which implies an even broader amplification bandwidth, thereby allowing for even shorter pulses. We carried out theoretical investigations to show the feasibility of such a set-up. Alongside these studies we will also present preliminary experimental results of an OPCPA system pumped by the output of our Ti:Sapphire ATLAS laser, currently delivering 350 mJ in 43 fs. An insight into the planned scaling of this technique to petawatt

  3. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source.

    Baillie, Devin; St Aubin, J; Fallone, B G; Steciw, S

    2013-04-01

    To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV∕m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show dmax is at 2.15 cm for a 10 × 10 cm(2) field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  4. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source

    Baillie, Devin [Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Aubin, J. St. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Steciw, S. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2013-04-15

    Purpose: To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. Methods: An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. Results: When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV/m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show d{sub max} is at 2.15 cm for a 10 Multiplication-Sign 10 cm{sup 2} field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. Conclusions: The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  5. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source

    Baillie, Devin; Aubin, J. St.; Fallone, B. G.; Steciw, S.

    2013-01-01

    Purpose: To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. Methods: An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. Results: When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV/m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show d max is at 2.15 cm for a 10 × 10 cm 2 field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. Conclusions: The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  6. Compression and radiation of high-power short rf pulses. II. A novel antenna array design with combined compressor/radiator elements

    Sirenko, Kostyantyn; Pazynin, Vadim L.; Sirenko, Yu K.; Bagci, Hakan

    2011-01-01

    The paper discusses the radiation of compressed high power short RF pulses using two different types of antennas: (i) A simple monopole antenna and (ii) a novel array design, where each of the elements is constructed by combining a compressor and a

  7. The Application of Cryogenic Laser Physics to the Development of High Average Power Ultra-Short Pulse Lasers

    David C. Brown

    2016-01-01

    Full Text Available Ultrafast laser physics continues to advance at a rapid pace, driven primarily by the development of more powerful and sophisticated diode-pumping sources, the development of new laser materials, and new laser and amplification approaches such as optical parametric chirped-pulse amplification. The rapid development of high average power cryogenic laser sources seems likely to play a crucial role in realizing the long-sought goal of powerful ultrafast sources that offer concomitant high peak and average powers. In this paper, we review the optical, thermal, thermo-optic and laser parameters important to cryogenic laser technology, recently achieved laser and laser materials progress, the progression of cryogenic laser technology, discuss the importance of cryogenic laser technology in ultrafast laser science, and what advances are likely to be achieved in the near-future.

  8. Compression and radiation of high-power short rf pulses. II. A novel antenna array design with combined compressor/radiator elements

    Sirenko, Kostyantyn

    2011-01-01

    The paper discusses the radiation of compressed high power short RF pulses using two different types of antennas: (i) A simple monopole antenna and (ii) a novel array design, where each of the elements is constructed by combining a compressor and a radiator. The studies on the monopole antenna demonstrate the possibility of a high power short RF pulse\\'s efficient radiation even using simple antennas. The studies on the novel array design demonstrate that a reduced size array with lower pulse distortion and power decay can be constructed by assembling the array from elements each of which integrates a compressor and a radiator. This design idea can be used with any type of antenna array; in this work it is applied to a phased array.

  9. A UV pre-ionized dual-wavelength short-pulse high-power CO{sub 2} laser facility for laser particle acceleration research

    Ebrahim, N A; Mouris, J F; Davis, R W

    1994-12-01

    In this report we describe the Chalk River dual-wavelength, short-pulse, single-mode, high-power CO{sub 2} laser facility for research in laser particle acceleration and CANDU materials modifications. The facility is designed and built around UV-preionized transversely-excited atmospheric-pressure (TEA) Lumonics CO{sub 2} laser discharge modules. Peak focussed power densities of up to 2 x 10{sup 14} W/cm{sup 2} in 500 ps pulses have been obtained. (author). 10 refs., 9 figs.

  10. High-power klystrons

    Siambis, John G.; True, Richard B.; Symons, R. S.

    1994-05-01

    Novel emerging applications in advanced linear collider accelerators, ionospheric and atmospheric sensing and modification and a wide spectrum of industrial processing applications, have resulted in microwave tube requirements that call for further development of high power klystrons in the range from S-band to X-band. In the present paper we review recent progress in high power klystron development and discuss some of the issues and scaling laws for successful design. We also discuss recent progress in electron guns with potential grading electrodes for high voltage with short and long pulse operation via computer simulations obtained from the code DEMEOS, as well as preliminary experimental results. We present designs for high power beam collectors.

  11. Ultra-short pulse delivery at high average power with low-loss hollow core fibers coupled to TRUMPF's TruMicro laser platforms for industrial applications

    Baumbach, S.; Pricking, S.; Overbuschmann, J.; Nutsch, S.; Kleinbauer, J.; Gebs, R.; Tan, C.; Scelle, R.; Kahmann, M.; Budnicki, A.; Sutter, D. H.; Killi, A.

    2017-02-01

    Multi-megawatt ultrafast laser systems at micrometer wavelength are commonly used for material processing applications, including ablation, cutting and drilling of various materials or cleaving of display glass with excellent quality. There is a need for flexible and efficient beam guidance, avoiding free space propagation of light between the laser head and the processing unit. Solid core step index fibers are only feasible for delivering laser pulses with peak powers in the kW-regime due to the optical damage threshold in bulk silica. In contrast, hollow core fibers are capable of guiding ultra-short laser pulses with orders of magnitude higher peak powers. This is possible since a micro-structured cladding confines the light within the hollow core and therefore minimizes the spatial overlap between silica and the electro-magnetic field. We report on recent results of single-mode ultra-short pulse delivery over several meters in a lowloss hollow core fiber packaged with industrial connectors. TRUMPF's ultrafast TruMicro laser platforms equipped with advanced temperature control and precisely engineered opto-mechanical components provide excellent position and pointing stability. They are thus perfectly suited for passive coupling of ultra-short laser pulses into hollow core fibers. Neither active beam launching components nor beam trackers are necessary for a reliable beam delivery in a space and cost saving packaging. Long term tests with weeks of stable operation, excellent beam quality and an overall transmission efficiency of above 85 percent even at high average power confirm the reliability for industrial applications.

  12. Prediction and measurement of the electromagnetic environment of high-power medium-wave and short-wave broadcast antennas in far field.

    Tang, Zhanghong; Wang, Qun; Ji, Zhijiang; Shi, Meiwu; Hou, Guoyan; Tan, Danjun; Wang, Pengqi; Qiu, Xianbo

    2014-12-01

    With the increasing city size, high-power electromagnetic radiation devices such as high-power medium-wave (MW) and short-wave (SW) antennas have been inevitably getting closer and closer to buildings, which resulted in the pollution of indoor electromagnetic radiation becoming worsened. To avoid such radiation exceeding the exposure limits by national standards, it is necessary to predict and survey the electromagnetic radiation by MW and SW antennas before constructing the buildings. In this paper, a modified prediction method for the far-field electromagnetic radiation is proposed and successfully applied to predict the electromagnetic environment of an area close to a group of typical high-power MW and SW wave antennas. Different from currently used simplified prediction method defined in the Radiation Protection Management Guidelines (H J/T 10. 3-1996), the new method in this article makes use of more information such as antennas' patterns to predict the electromagnetic environment. Therefore, it improves the prediction accuracy significantly by the new feature of resolution at different directions. At the end of this article, a comparison between the prediction data and the measured results is given to demonstrate the effectiveness of the proposed new method. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Development of novel high power-short time (HPST) microwave assisted commercial decontamination process for dried turmeric powder (Curcuma Longa L.).

    Behera, G; Sutar, P P; Aditya, S

    2017-11-01

    The commercially available dry turmeric powder at 10.34% d.b. moisture content was decontaminated using microwaves at high power density for short time. To avoid the loss of moisture from turmeric due to high microwave power, the drying kinetics were modelled and considered during optimization of microwave decontamination process. The effect of microwave power density (10, 33.5 and 57 W g -1 ), exposure time (10, 20 and 30 s) and thickness of turmeric layer (1, 2 and 3 mm) on total plate, total yeast and mold (YMC) counts, color change (∆E), average final temperature of the product (T af ), water activity (a w ), Page model rate constant (k) and total moisture loss (ML) was studied. The perturbation analysis was carried out for all variables. It was found that to achieve more than one log reduction in yeast and mold count, a substantial reduction in moisture content takes place leading to the reduced output. The microwave power density significantly affected the YMC, T af and a w of turmeric powder. But the thickness of sample and microwave exposure time showed effect only on T af , a w and ML. The colour of turmeric and Page model rate constant were not significantly changed during the process as anticipated. The numerical optimization was done at 57.00 W g -1 power density, 1.64 mm thickness of sample layer and 30 s exposure time. It resulted into 1.6 × 10 7 CFU g -1 YMC, 82.71 °C T af , 0.383 a w and 8.41% (d.b.) final moisture content.

  14. Non-Fourier conduction model with thermal source term of ultra short high power pulsed laser ablation and temperature evolvement before melting

    Zhang Duanming; Li, Li; Li Zhihua; Guan Li; Tan Xinyu

    2005-01-01

    A non-Fourier conduction model with heat source term is presented to study the target temperature evolvement when the target is radiated by high power (the laser intensity is above 10 9 w/cm 2 ) and ultra short (the pulse width is less than 150 ps) pulsed laser. By Laplace transform, the analytical expression of the space- and time-dependence of temperature is derived. Then as an example of aluminum target, the target temperature evolvement is simulated. Compared with the results of Fourier conduction model and non-Fourier model without heat source term, it is found that the effect of non-Fourier conduction is notable and the heat source plays an important role during non-Fourier conduction which makes surface temperature ascending quickly with time. Meanwhile, the corresponding physical mechanism is analyzed theoretically

  15. Compression and radiation of high-power short rf pulses. I. Energy accumulation in direct-flow waveguide compressors

    Sirenko, Kostyantyn; Pazynin, Vadim L.; Sirenko, Yu K.; Bagci, Hakan

    2011-01-01

    Proper design of efficient requires precise understanding of the physics pertinent to energy accumulation and exhaust processes in resonant waveguide cavities. In this paper, practically for the first time these highly non-monotonic transient processes are studied in detail using a rigorous time-domain approach. Additionally, influence of the geometrical design and excitation parameters on the compressor's performance is quantified in detail.

  16. Compression and radiation of high-power short rf pulses. I. Energy accumulation in direct-flow waveguide compressors

    Sirenko, Kostyantyn

    2011-01-01

    Proper design of efficient requires precise understanding of the physics pertinent to energy accumulation and exhaust processes in resonant waveguide cavities. In this paper, practically for the first time these highly non-monotonic transient processes are studied in detail using a rigorous time-domain approach. Additionally, influence of the geometrical design and excitation parameters on the compressor\\'s performance is quantified in detail.

  17. Short time ahead wind power production forecast

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-01-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast. (paper)

  18. Short time ahead wind power production forecast

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-09-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast.

  19. Short-term wind power prediction

    Joensen, Alfred K.

    2003-01-01

    , and to implement these models and methods in an on-line software application. The economical value of having predictions available is also briefly considered. The summary report outlines the background and motivation for developing wind power prediction models. The meteorological theory which is relevant......The present thesis consists of 10 research papers published during the period 1997-2002 together with a summary report. The objective of the work described in the thesis is to develop models and methods for calculation of high accuracy predictions of wind power generated electricity...

  20. Short-Term Wind Speed Forecasting for Power System Operations

    Zhu, Xinxin

    2012-04-01

    The emphasis on renewable energy and concerns about the environment have led to large-scale wind energy penetration worldwide. However, there are also significant challenges associated with the use of wind energy due to the intermittent and unstable nature of wind. High-quality short-term wind speed forecasting is critical to reliable and secure power system operations. This article begins with an overview of the current status of worldwide wind power developments and future trends. It then reviews some statistical short-term wind speed forecasting models, including traditional time series approaches and more advanced space-time statistical models. It also discusses the evaluation of forecast accuracy, in particular, the need for realistic loss functions. New challenges in wind speed forecasting regarding ramp events and offshore wind farms are also presented. © 2012 The Authors. International Statistical Review © 2012 International Statistical Institute.

  1. CSTI High Capacity Power

    Winter, J.M.

    1989-01-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed

  2. Pulsed high-power beams

    Reginato, L.L.; Birx, D.L.

    1988-01-01

    The marriage of induction linac technology with nonlinear magnetic modulators has produced some unique capabilities. It is now possible to produce short-pulse electron beams with average currents measured in amperes, at gradients approaching 1-MeV/m, and with power efficiencies exceeding 50%. This paper reports on a 70-MeV, 3-kA induction accelerator (ETA II) constructed at the Lawrence Livermore National Laboratory that incorporates the pulse technology concepts that have evolved over the past several years. The ETA II is a linear induction accelerator and provides a test facility for demonstration of the high-average-power components and high-brightness sources used in such accelerators. The pulse drive of the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak-power capability, repetition rates exceeding 1 kHz, and excellent reliability

  3. Stochastic Optimal Wind Power Bidding Strategy in Short-Term Electricity Market

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

    2012-01-01

    Due to the fluctuating nature and non-perfect forecast of the wind power, the wind power owners are penalized for the imbalance costs of the regulation, when they trade wind power in the short-term liberalized electricity market. Therefore, in this paper a formulation of an imbalance cost...... minimization problem for trading wind power in the short-term electricity market is described, to help the wind power owners optimize their bidding strategy. Stochastic optimization and a Monte Carlo method are adopted to find the optimal bidding strategy for trading wind power in the short-term electricity...... market in order to deal with the uncertainty of the regulation price, the activated regulation of the power system and the forecasted wind power generation. The Danish short-term electricity market and a wind farm in western Denmark are chosen as study cases due to the high wind power penetration here...

  4. Online Short-term Solar Power Forecasting

    Bacher, Peder; Madsen, Henrik; Nielsen, Henrik Aalborg

    2011-01-01

    This poster presents two approaches to online forecasting of power production from PV systems. The methods are suited for online forecasting in many applications and here they are used to predict hourly values of solar power for horizons up to 32 hours.......This poster presents two approaches to online forecasting of power production from PV systems. The methods are suited for online forecasting in many applications and here they are used to predict hourly values of solar power for horizons up to 32 hours....

  5. Variable Power, Short Microwave Pulses Generation using a CW Magnetron

    CIUPA, R.

    2011-05-01

    Full Text Available Fine control of microwave power radiation in medical and scientific applications is a challenging task. Since a commercial Continuous Wave (CW magnetron is the most inexpensive microwave device available today on the market, it becomes the best candidate for a microwave power generator used in medical diathermy and hyperthermia treatments or high efficiency chemical reactions using microwave reactors as well. This article presents a new method for driving a CW magnetron with short pulses, using a modified commercial Zero Voltage Switching (ZVS inverter, software driven by a custom embedded system. The microwave power generator designed with this method can be programmed for output microwave pulses down to 1% of the magnetron's power and allows microwave low frequency pulse modulation in the range of human brain electrical activity, intended for medical applications. Microwave output power continuous control is also possible with the magnetron running in the oscillating area, using a dual frequency Pulse Width Modulation (PWM, where the low frequency PWM pulse is modulating a higher resonant frequency required by the ZVS inverter's transformer. The method presented allows a continuous control of both power and energy (duty-cycle at the inverter's output.

  6. Resonant High Power Combiners

    Langlois, Michel; Peillex-Delphe, Guy

    2005-01-01

    Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

  7. Online short-term solar power forecasting

    Bacher, Peder; Madsen, Henrik; Nielsen, Henrik Aalborg

    2009-01-01

    This paper describes a new approach to online forecasting of power production from PV systems. The method is suited to online forecasting in many applications and in this paper it is used to predict hourly values of solar power for horizons of up to 36 hours. The data used is fifteen......-minute observations of solar power from 21 PV systems located on rooftops in a small village in Denmark. The suggested method is a two-stage method where first a statistical normalization of the solar power is obtained using a clear sky model. The clear sky model is found using statistical smoothing techniques....... Then forecasts of the normalized solar power are calculated using adaptive linear time series models. Both autoregressive (AR) and AR with exogenous input (ARX) models are evaluated, where the latter takes numerical weather predictions (NWPs) as input. The results indicate that for forecasts up to two hours...

  8. High power microwaves

    Benford, James; Schamiloglu, Edl

    2016-01-01

    Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

  9. High-energy, short-pulse, carbon-dioxide lasers

    Fenstermacher, C.A.

    1979-01-01

    Lasers for fusion application represent a special class of short-pulse generators; not only must they generate extremely short temporal pulses of high quality, but they must do this at ultra-high powers and satisfy other stringent requirements by this application. This paper presents the status of the research and development of carbon-dioxide laser systems at the Los Alamos Scientific Laboratory, vis-a-vis the fusion requirements

  10. Short-Term Solar Collector Power Forecasting

    Bacher, Peder; Madsen, Henrik; Perers, Bengt

    2011-01-01

    This paper describes a new approach to online forecasting of power output from solar thermal collectors. The method is suited for online forecasting in many applications and in this paper it is applied to predict hourly values of power from a standard single glazed large area flat plate collector...... enabling tracking of changes in the system and in the surrounding conditions, such as decreasing performance due to wear and dirt, and seasonal changes such as leaves on trees. This furthermore facilitates remote monitoring and check of the system....

  11. Control over Permissible Short Emergency Overloads in Power Transformers

    V. A. Anischenko

    2010-01-01

    Full Text Available The paper proposes a method for determination a permissible duration of short intermittent overloads of power transformers that permits to avoid non-permissible over-heating of winding insulation and fully utilize overloading transformer ability.

  12. Short circuit protection for a power distribution system

    Owen, J. R., III

    1969-01-01

    Sensing circuit detects when the output from a matrix is present and when it should be present. The circuit provides short circuit protection for a power distribution system where the selection of the driven load is accomplished by digital logic.

  13. Switching power converters medium and high power

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  14. High-power pulsed lasers

    Holzrichter, J.F.

    1980-01-01

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization

  15. Investigation and Classification of Short-Circuit Failure Modes Based on Three-Dimensional Safe Operating Area for High-Power IGBT Modules

    Chen, Yuxiang; Li, Wuhua; Iannuzzo, Francesco

    2018-01-01

    is implemented to motivate advanced contributions in future dependence research of device short-circuit failure modes on temperature. Consequently, a comprehensive and thoughtful review of where the development of short-circuit failure mode research works of IGBT stands and is heading is provided....

  16. Short-Term Wind Power Forecasting Using the Enhanced Particle Swarm Optimization Based Hybrid Method

    Wen-Yeau Chang

    2013-01-01

    High penetration of wind power in the electricity system provides many challenges to power system operators, mainly due to the unpredictability and variability of wind power generation. Although wind energy may not be dispatched, an accurate forecasting method of wind speed and power generation can help power system operators reduce the risk of an unreliable electricity supply. This paper proposes an enhanced particle swarm optimization (EPSO) based hybrid forecasting method for short-term wi...

  17. A Computer Program for Short Circuit Analysis of Electric Power ...

    The Short Circuit Analysis Program (SCAP) is to be used to assess the composite effects of unbalanced and balanced faults on the overall reliability of electric power system. The program uses the symmetrical components method to compute all phase and sequence quantities for any bus or branch of a given power network ...

  18. High-voltage short-fall pulse generator

    Dolbilov, G.V.; Fateev, A.A.; Petrov, V.A.

    1986-01-01

    Powerful high-voltage pulses with short fall times and relatively low afterpulse amplitude are required for the deflection systems of accelerators. A generator is described that provides, into a 75-ohm load, a voltage pulse of up to 100 kV with a fall time of less than 1 nsec and a relative afterpulse amplitude of less than or equal to 15%. The generator employs a short-circuited ferrite-filled line in which shock waves are formed. A magnetic section is used to increase power. The switch is a TGI1-2500/50 thyratron. The main causes of afterpulses and methods for reducing their amplitude are examined

  19. Error analysis of short term wind power prediction models

    De Giorgi, Maria Grazia; Ficarella, Antonio; Tarantino, Marco

    2011-01-01

    The integration of wind farms in power networks has become an important problem. This is because the electricity produced cannot be preserved because of the high cost of storage and electricity production must follow market demand. Short-long-range wind forecasting over different lengths/periods of time is becoming an important process for the management of wind farms. Time series modelling of wind speeds is based upon the valid assumption that all the causative factors are implicitly accounted for in the sequence of occurrence of the process itself. Hence time series modelling is equivalent to physical modelling. Auto Regressive Moving Average (ARMA) models, which perform a linear mapping between inputs and outputs, and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS), which perform a non-linear mapping, provide a robust approach to wind power prediction. In this work, these models are developed in order to forecast power production of a wind farm with three wind turbines, using real load data and comparing different time prediction periods. This comparative analysis takes in the first time, various forecasting methods, time horizons and a deep performance analysis focused upon the normalised mean error and the statistical distribution hereof in order to evaluate error distribution within a narrower curve and therefore forecasting methods whereby it is more improbable to make errors in prediction. (author)

  20. Error analysis of short term wind power prediction models

    De Giorgi, Maria Grazia; Ficarella, Antonio; Tarantino, Marco [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via per Monteroni, 73100 Lecce (Italy)

    2011-04-15

    The integration of wind farms in power networks has become an important problem. This is because the electricity produced cannot be preserved because of the high cost of storage and electricity production must follow market demand. Short-long-range wind forecasting over different lengths/periods of time is becoming an important process for the management of wind farms. Time series modelling of wind speeds is based upon the valid assumption that all the causative factors are implicitly accounted for in the sequence of occurrence of the process itself. Hence time series modelling is equivalent to physical modelling. Auto Regressive Moving Average (ARMA) models, which perform a linear mapping between inputs and outputs, and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS), which perform a non-linear mapping, provide a robust approach to wind power prediction. In this work, these models are developed in order to forecast power production of a wind farm with three wind turbines, using real load data and comparing different time prediction periods. This comparative analysis takes in the first time, various forecasting methods, time horizons and a deep performance analysis focused upon the normalised mean error and the statistical distribution hereof in order to evaluate error distribution within a narrower curve and therefore forecasting methods whereby it is more improbable to make errors in prediction. (author)

  1. Short-term Power Load Forecasting Based on Balanced KNN

    Lv, Xianlong; Cheng, Xingong; YanShuang; Tang, Yan-mei

    2018-03-01

    To improve the accuracy of load forecasting, a short-term load forecasting model based on balanced KNN algorithm is proposed; According to the load characteristics, the historical data of massive power load are divided into scenes by the K-means algorithm; In view of unbalanced load scenes, the balanced KNN algorithm is proposed to classify the scene accurately; The local weighted linear regression algorithm is used to fitting and predict the load; Adopting the Apache Hadoop programming framework of cloud computing, the proposed algorithm model is parallelized and improved to enhance its ability of dealing with massive and high-dimension data. The analysis of the household electricity consumption data for a residential district is done by 23-nodes cloud computing cluster, and experimental results show that the load forecasting accuracy and execution time by the proposed model are the better than those of traditional forecasting algorithm.

  2. Accurate Short-Term Power Forecasting of Wind Turbines: The Case of Jeju Island’s Wind Farm

    BeomJun Park; Jin Hur

    2017-01-01

    Short-term wind power forecasting is a technique which tells system operators how much wind power can be expected at a specific time. Due to the increasing penetration of wind generating resources into the power grids, short-term wind power forecasting is becoming an important issue for grid integration analysis. The high reliability of wind power forecasting can contribute to the successful integration of wind generating resources into the power grids. To guarantee the reliability of forecas...

  3. High Power Density Motors

    Kascak, Daniel J.

    2004-01-01

    With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

  4. High-power electronics

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  5. High Power Vanadate lasers

    Strauss

    2006-07-01

    Full Text Available stream_source_info Strauss1_2006.pdf.txt stream_content_type text/plain stream_size 3151 Content-Encoding UTF-8 stream_name Strauss1_2006.pdf.txt Content-Type text/plain; charset=UTF-8 Laser Research Institute... University of Stellenbosch www.laser-research.co.za High Power Vanadate lasers H.J.Strauss, Dr. C. Bollig, R.C. Botha, Prof. H.M. von Bergmann, Dr. J.P. Burger Aims 1) To develop new techniques to mount laser crystals, 2) compare the lasing properties...

  6. High power coaxial ubitron

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  7. High-repetition-rate short-pulse gas discharge.

    Tulip, J; Seguin, H; Mace, P N

    1979-09-01

    A high-average-power short-pulse gas discharge is described. This consists of a volume-preionized transverse discharge of the type used in gas lasers driven by a Blumlein energy storage circuit. The Blumlein circuit is fabricated from coaxial cable, is pulse-charged from a high-repetition-rate Marx-bank generator, and is switched by a high-repetition-rate segmented rail gap. The operation of this discharge under conditions typical of rare-gas halide lasers is described. A maximum of 900 pps was obtained, giving a power flow into the discharge of 30 kW.

  8. High power communication satellites power systems study

    Josloff, A.T.; Peterson, J.R.

    1994-01-01

    This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

  9. EURISOL High Power Targets

    Kadi, Y; Lindroos, M; Ridikas, D; Stora, T; Tecchio, L; CERN. Geneva. BE Department

    2009-01-01

    Modern Nuclear Physics requires access to higher yields of rare isotopes, that relies on further development of the In-flight and Isotope Separation On-Line (ISOL) production methods. The limits of the In-Flight method will be applied via the next generation facilities FAIR in Germany, RIKEN in Japan and RIBF in the USA. The ISOL method will be explored at facilities including ISAC-TRIUMF in Canada, SPIRAL-2 in France, SPES in Italy, ISOLDE at CERN and eventually at the very ambitious multi-MW EURISOL facility. ISOL and in-flight facilities are complementary entities. While in-flight facilities excel in the production of very short lived radioisotopes independently of their chemical nature, ISOL facilities provide high Radioisotope Beam (RIB) intensities and excellent beam quality for 70 elements. Both production schemes are opening vast and rich fields of nuclear physics research. In this article we will introduce the targets planned for the EURISOL facility and highlight some of the technical and safety cha...

  10. SHORT COMMUNICATION High prevalence of Plasmodium ...

    Dell

    Volume 20, Number 1, January 2018. 1. SHORT COMMUNICATION ... This study was designed to establish the prevalence of Plasmodium falciparum malaria among HIV infected populations. ... The prevalence of P. falciparum was high among HIV seropositive individuals in the Lake Victoria Zone, which calls for additional ...

  11. A short history of the CANDU nuclear power system

    Brooks, G L

    1993-04-01

    This paper provides a short historical summary of the evolution of the CANDU nuclear power system with emphasis on the roles played by Ontario Hydro and private sector companies in Ontario in collaboration with Atomic Energy of Canada Limited (AECL). (author). 1 fig., 61 refs.

  12. A short history of the CANDU nuclear power system

    Brooks, G.L.

    1993-04-01

    This paper provides a short historical summary of the evolution of the CANDU nuclear power system with emphasis on the roles played by Ontario Hydro and private sector companies in Ontario in collaboration with Atomic Energy of Canada Limited (AECL). (author). 1 fig., 61 refs

  13. Estimates of SASE power in the short wavelength region

    Kim, Kwang-Je.

    1992-03-01

    Given a sufficiently bright electron beam, the self-amplified-spontaneous emission (SASE) can provide gigawatts of short wavelength coherent radiation. The advantages of SASE approach are that is requires neither optical cavity nor an imput seed laser. In this note, we estimate the peak power performance of SASE for wavelengths shorter than 1000 Angstrom. At each wavelength, we calculate the saturated power from a uniform parameter undulator and the enhanced power from a tapered undulator. The method described here is an adaptation of that discussed by L.H. Yu, who discussed the harmonic generation scheme with seeded laser, to the case of SASE

  14. Nuclear power flies high

    Friedman, S.T.

    1983-01-01

    Nuclear power in aircraft, rockets and satellites is discussed. No nuclear-powered rockets or aircraft have ever flown, but ground tests were successful. Nuclear reactors are used in the Soviet Cosmos serles of satellites, but only one American satellite, the SNAP-10A, contained a reactor. Radioisotope thermoelectric generators, many of which use plutonium 238, have powered more than 20 satellites launched into deep space by the U.S.A

  15. Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

    Ahuja, Sumit; Shukla, Sandeep Kumar

    2012-01-01

    Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

  16. Short-Term Planning of Hybrid Power System

    Knežević, Goran; Baus, Zoran; Nikolovski, Srete

    2016-07-01

    In this paper short-term planning algorithm for hybrid power system consist of different types of cascade hydropower plants (run-of-the river, pumped storage, conventional), thermal power plants (coal-fired power plants, combined cycle gas-fired power plants) and wind farms is presented. The optimization process provides a joint bid of the hybrid system, and thus making the operation schedule of hydro and thermal power plants, the operation condition of pumped-storage hydropower plants with the aim of maximizing profits on day ahead market, according to expected hourly electricity prices, the expected local water inflow in certain hydropower plants, and the expected production of electrical energy from the wind farm, taking into account previously contracted bilateral agreement for electricity generation. Optimization process is formulated as hourly-discretized mixed integer linear optimization problem. Optimization model is applied on the case study in order to show general features of the developed model.

  17. Optical engineering for high power laser applications

    Novaro, M.

    1993-01-01

    Laser facilities for Inertial Confinement Fusion (I.C.F.) experiments require laser and X ray optics able to withstand short pulse conditions. After a brief recall of high power laser system arrangements and of the characteristics of their optics, the authors will present some X ray optical developments

  18. Gate Drive For High Speed, High Power IGBTs

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

    2007-06-18

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

  19. Gate Drive For High Speed, High Power IGBTs

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; SLAC

    2007-01-01

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3(micro)S with a rate of current rise of more than 10000A/(micro)S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt

  20. Change of the high-latitude ionosphere during heating by a powerful short radio wave of the EISCAT/Heating complex according to signals of the GLONASS satellite and the incoherent scattering radar

    Tereshchenko E. D.

    2018-03-01

    Full Text Available Results of observations of variations of temperature, electron concentration and total electron content of the high-latitude region of the ionosphere during its modification by powerful short radio waves of the heating complex EISCAT/Heating (Tromsø, Norway according to signals of the GLONASS satellites and the incoherent scattering UHF EISCAT radar (Tromsø, Norway have been provided. The geometry of passes of the GLONASS and GPS satellites for operating conditions of the heating complex in Tromsø has been considered. It has been shown that during the experiments on the EISCAT/Heating complex for the study of the modified structure of the high-latitude ionosphere it is more convenient to use the GLONASS satellites. Parameters of orbits of these satellites allow researching changes of total electron content in the direction along the geomagnetic field line at the place of observation. It has been shown that during heating of the ionosphere by powerful short radio waves its structure is becoming an irregular one. Operation of the heating complex in the mode "switched on – switched off" has caused appearance of wavy variations of total electron content with the periods close to the heating period. The main features of behavior of the total electron content in the case of the continuous heating of the ionosphere in the direction of the magnetic zenith according to the GLONASS satellite are: reduction of total electron content in the central zone of the antenna diagram, i. e. in the direction of the magnetic zenith, and presence of the increased values of total electron content at the edges of the heating zone. According to the incoherent scattering radar the heating of the ionosphere by the powerful short radio wave has created the region of the increased electron temperature and electron concentration along the direction of the magnetic zenith. The behavior of total electron content according to the GLONASS satellite and the radar of

  1. High Efficiency Power Converter for Low Voltage High Power Applications

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

  2. A new ensemble model for short term wind power prediction

    Madsen, Henrik; Albu, Razvan-Daniel; Felea, Ioan

    2012-01-01

    As the objective of this study, a non-linear ensemble system is used to develop a new model for predicting wind speed in short-term time scale. Short-term wind power prediction becomes an extremely important field of research for the energy sector. Regardless of the recent advancements in the re-search...... of prediction models, it was observed that different models have different capabilities and also no single model is suitable under all situations. The idea behind EPS (ensemble prediction systems) is to take advantage of the unique features of each subsystem to detain diverse patterns that exist in the dataset...

  3. High power communication satellites power systems study

    Josloff, Allan T.; Peterson, Jerry R.

    1995-01-01

    This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

  4. Improved Short-Circuit Protection for Power Cells in Series

    Davies, Francis

    2008-01-01

    A scheme for protection against short circuits has been devised for series strings of lithium electrochemical cells that contain built-in short-circuit protection devices, which go into a high-resistance, current-limiting state when heated by excessive current. If cells are simply connected in a long series string to obtain a high voltage and a short circuit occurs, whichever short-circuit protection device trips first is exposed to nearly the full string voltage, which, typically, is large enough to damage the device. Depending on the specific cell design, the damage can defeat the protective function, cause a dangerous internal short circuit in the affected cell, and/or cascade to other cells. In the present scheme, reverse diodes rated at a suitably high current are connected across short series sub-strings, the lengths of which are chosen so that when a short-circuit protection device is tripped, the voltage across it does not exceed its rated voltage. This scheme preserves the resetting properties of the protective devices. It provides for bypassing of cells that fail open and limits cell reversal, though not as well as does the more-expensive scheme of connecting a diode across every cell.

  5. High Power Orbit Transfer Vehicle

    Gulczinski, Frank

    2003-01-01

    ... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...

  6. High Efficiency Power Converter for Low Voltage High Power Applications

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

  7. Short-term economics of virtual power plants

    Kok, J.K.

    2009-08-01

    The Virtual Power Plant (VPP) has gained an increasing interest over the last few years. A VPP is a flexible representation of a portfolio of Distributed Energy Resources (DER: distributed generation, demand response and electricity storage). One of the key activities of a VPP is the delivery of (near-)real-time balancing services. In order to operate such a (near-)real-time coordination activity optimally, the VPP needs to maintain a dynamic merit-order list of all DER participating in the VPP. In order to make optimal decisions based on this list, the merit order needs to be based on the true marginal cost (or marginal benefit in case of demand response) of the individual DER units. The marginal electricity costs of most types of DER are highly dependent on local context and, hence, change over time. From analysis of the short-term bid strategies of various DER units, the existence of a bid strategy spectrum becomes clear. On one end of the spectrum, bidding strategies are based straightforwardly on true marginal cost or benefit. Further along the spectrum, optimal bidding strategies become less dependent on marginal cost levels and more on the price dynamics in the (VPP) market context. These results are relevant for VPP operations both from business and technical perspectives.

  8. High power excimer laser

    Oesterlin, P.; Muckenheim, W.; Basting, D.

    1988-01-01

    Excimer lasers emitting more than 200 W output power are not commercially available. A significant increase requires new technological efforts with respect to both the gas circulation and the discharge system. The authors report how a research project has yielded a laser which emits 0.5 kW at 308 nm when being UV preionized and operated at a repetition rate of 300 Hz. The laser, which is capable of operating at 500 Hz, can be equipped with an x-ray preionization module. After completing this project 1 kW output power will be available

  9. High average power supercontinuum sources

    The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium.

  10. Short-time action electric generators to power physical devices

    Glebov, I.A.; Kasharskij, Eh.G.; Rutberg, F.G.; Khutoretskij, G.M.

    1982-01-01

    Requirements to be met by power-supply sources of the native electrophysical facilities have been analyzed and trends in designing foreign electric machine units of short-time action have been considered. Specifications of a generator, manufactured in the form of synchronous bipolar turbogenerator with an all-forged rotor with indirect air cooling of the rotor and stator windings are presented. Front parts of the stator winding are additionally fixed using glass-textolite rings, brackets and gaskets. A flywheel, manufactured in the form of all-forged steel cylinder is joined directly with the generator rotor by means of a half-coupling. An acceleration asynchronous engine with a phase rotor of 4 MW nominal capacity is located on the opposite side of the flywheel. The generator peak power is 242 MVxA; power factor = 0.9; energy transferred to the load 5per 1 pulse =00 MJ; the flywheel weight 81 t

  11. Compact high-power terahertz radiation source

    G. A. Krafft

    2004-06-01

    Full Text Available In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator on the return leg, is discussed. Because the beam is recirculated and not stored, short bunches may be produced that radiate coherently in the undulator, yielding exceptionally high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes, limits the charge-per-bunch possible in such a device.

  12. Short-Term Power Plant GHG Emissions Forecasting Model

    Vidovic, D.

    2016-01-01

    In 2010, the share of greenhouse gas (GHG) emissions from power generation in the total emissions at the global level was about 25 percent. From January 1st, 2013 Croatian facilities have been involved in the European Union Emissions Trading System (EU ETS). The share of the ETS sector in total GHG emissions in Croatia in 2012 was about 30 percent, where power plants and heat generation facilities contributed to almost 50 percent. Since 2013 power plants are obliged to purchase all emission allowances. The paper describes the short-term climate forecasting model of greenhouse gas emissions from power plants while covering the daily load diagram of the system. Forecasting is done on an hourly domain typically for one day, it is possible and more days ahead. Forecasting GHG emissions in this way would enable power plant operators to purchase additional or sell surplus allowances on the market at the time. Example that describes the operation of the above mentioned forecasting model is given at the end of the paper.(author).

  13. A Simple Short Circuit Analysis for Power Networks

    Koşalay İlhan

    2016-01-01

    Full Text Available This study investigates the transient behavior of short circuits in power circuits. The circuit consists of two part; input part and load part. These two parts are connected with a circuit breaker switch. The circuit works in two modes; first mode is when the switch is open and second mode is when the switch is closed. This study analyses the circuit when the switch is closed. The analysis is done with different types of closing angle. The analysis is done by forming state equations and those equations are solved numerically by using Matlab. The analysis and conclusion is performed by observing the behaviors of the graphs.

  14. High-powered manoeuvres

    Anaïs Schaeffer

    2013-01-01

    This week, CERN received the latest new transformers for the SPS. Stored in pairs in 24-tonne steel containers, these transformers will replace the old models, which have been in place since 1981.     The transformers arrive at SPS's access point 4 (BA 4). During LS1, the TE-EPC Group will be replacing all of the transformers for the main converters of the SPS. This renewal campaign is being carried out as part of the accelerator consolidation programme, which began at the start of April and will come to an end in November. It involves 80 transformers: 64 with a power of 2.6 megavolt-amperes (MVA) for the dipole magnets, and 16 with 1.9 MVA for the quadrupoles. These new transformers were manufactured by an Italian company and are being installed outside the six access points of the SPS by the EN-HE Group, using CERN's 220-tonne crane. They will contribute to the upgrade of the SPS, which should thus continue to operate as the injector for the LHC until 2040....

  15. Autonomously managed high power systems

    Weeks, D.J.; Bechtel, R.T.

    1985-01-01

    The need for autonomous power management capabilities will increase as the power levels of spacecraft increase into the multi-100 kW range. The quantity of labor intensive ground and crew support consumed by the 9 kW Skylab cannot be afforded in support of a 75-300 kW Space Station or high power earth orbital and interplanetary spacecraft. Marshall Space Flight Center is managing a program to develop necessary technologies for high power system autonomous management. To date a reference electrical power system and automation approaches have been defined. A test facility for evaluation and verification of management algorithms and hardware has been designed with the first of the three power channel capability nearing completion

  16. Wavelet decomposition and neuro-fuzzy hybrid system applied to short-term wind power

    Fernandez-Jimenez, L.A.; Mendoza-Villena, M. [La Rioja Univ., Logrono (Spain). Dept. of Electrical Engineering; Ramirez-Rosado, I.J.; Abebe, B. [Zaragoza Univ., Zaragoza (Spain). Dept. of Electrical Engineering

    2010-03-09

    Wind energy has become increasingly popular as a renewable energy source. However, the integration of wind farms in the electrical power systems presents several problems, including the chaotic fluctuation of wind flow which results in highly varied power generation from a wind farm. An accurate forecast of wind power generation has important consequences in the economic operation of the integrated power system. This paper presented a new statistical short-term wind power forecasting model based on wavelet decomposition and neuro-fuzzy systems optimized with a genetic algorithm. The paper discussed wavelet decomposition; the proposed wind power forecasting model; and computer results. The original time series, the mean electric power generated in a wind farm, was decomposing into wavelet coefficients that were utilized as inputs for the forecasting model. The forecasting results obtained with the final models were compared to those obtained with traditional forecasting models showing a better performance for all the forecasting horizons. 13 refs., 1 tab., 4 figs.

  17. Applications of high power microwaves

    Benford, J.; Swegle, J.

    1993-01-01

    The authors address a number of applications for HPM technology. There is a strong symbiotic relationship between a developing technology and its emerging applications. New technologies can generate new applications. Conversely, applications can demand development of new technological capability. High-power microwave generating systems come with size and weight penalties and problems associated with the x-radiation and collection of the electron beam. Acceptance of these difficulties requires the identification of a set of applications for which high-power operation is either demanded or results in significant improvements in peRFormance. The authors identify the following applications, and discuss their requirements and operational issues: (1) High-energy RF acceleration; (2) Atmospheric modification (both to produce artificial ionospheric mirrors for radio waves and to save the ozone layer); (3) Radar; (4) Electronic warfare; and (5) Laser pumping. In addition, they discuss several applications requiring high average power than border on HPM, power beaming and plasma heating

  18. Modular High Voltage Power Supply

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  19. Short-term load forecasting of power system

    Xu, Xiaobin

    2017-05-01

    In order to ensure the scientific nature of optimization about power system, it is necessary to improve the load forecasting accuracy. Power system load forecasting is based on accurate statistical data and survey data, starting from the history and current situation of electricity consumption, with a scientific method to predict the future development trend of power load and change the law of science. Short-term load forecasting is the basis of power system operation and analysis, which is of great significance to unit combination, economic dispatch and safety check. Therefore, the load forecasting of the power system is explained in detail in this paper. First, we use the data from 2012 to 2014 to establish the partial least squares model to regression analysis the relationship between daily maximum load, daily minimum load, daily average load and each meteorological factor, and select the highest peak by observing the regression coefficient histogram Day maximum temperature, daily minimum temperature and daily average temperature as the meteorological factors to improve the accuracy of load forecasting indicators. Secondly, in the case of uncertain climate impact, we use the time series model to predict the load data for 2015, respectively, the 2009-2014 load data were sorted out, through the previous six years of the data to forecast the data for this time in 2015. The criterion for the accuracy of the prediction is the average of the standard deviations for the prediction results and average load for the previous six years. Finally, considering the climate effect, we use the BP neural network model to predict the data in 2015, and optimize the forecast results on the basis of the time series model.

  20. Fault analysis and strategy of high pulsed power supply for high power laser

    Liu Kefu; Qin Shihong; Li Jin; Pan Yuan; Yao Zonggan; Zheng Wanguo; Guo Liangfu; Zhou Peizhang; Li Yizheng; Chen Dehuai

    2001-01-01

    according to the requirements of driving flash-lamp, a high pulsed power supply (PPS) based on capacitors as energy storage elements is designed. The author analyzes in detail the faults of high pulsed power supply for high power laser. Such as capacitor internal short-circuit, main bus breakdown to ground, flashlamp sudden short or break. The fault current and voltage waveforms were given by circuit simulations. Based on the analysis and computation, the protection strategy with the fast fuse and ZnO was put forward, which can reduce the damage of PPS to the lower extent and provide the personnel safe and collateral property from the all threats. The preliminary experiments demonstrated that the design of the PPS can satisfy the project requirements

  1. High beam quality and high energy short-pulse laser with MOPA

    Jin, Quanwei; Pang, Yu; Jiang, JianFeng; Tan, Liang; Cui, Lingling; Wei, Bin; Sun, Yinhong; Tang, Chun

    2018-03-01

    A high energy, high beam quality short-pulse diode-pumped Nd:YAG master oscillator power-amplifier (MOPA) laser with two amplifier stages is demonstrated. The two-rod birefringence compensation was used as beam quality controlling methods, which presents a short-pulse energy of 40 mJ with a beam quality value of M2 = 1.2 at a repetition rate of 400Hz. The MOPA system delivers a short-pulse energy of 712.5 mJ with a pulse width of 12.4 ns.The method of spherical aberration compensation is improved the beam quality, a M2 factor of 2.3 and an optical-to-optical efficiency of 27.7% is obtained at the maximum laser out power.The laser obtained 1.4J out energy with polarization integration.

  2. High power klystrons for efficient reliable high power amplifiers

    Levin, M.

    1980-11-01

    This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

  3. Short-term wind power forecasting: probabilistic and space-time aspects

    Tastu, Julija

    work deals with the proposal and evaluation of new mathematical models and forecasting methods for short-term wind power forecasting, accounting for space-time dynamics based on geographically distributed information. Different forms of power predictions are considered, starting from traditional point...... into the corresponding models are analysed. As a final step, emphasis is placed on generating space-time trajectories: this calls for the prediction of joint multivariate predictive densities describing wind power generation at a number of distributed locations and for a number of successive lead times. In addition......Optimal integration of wind energy into power systems calls for high quality wind power predictions. State-of-the-art forecasting systems typically provide forecasts for every location individually, without taking into account information coming from the neighbouring territories. It is however...

  4. The Jefferson Lab High Power Light Source

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  5. High power laser exciter accelerators

    Martin, T.H.

    1975-01-01

    Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

  6. High power fast ramping power supplies

    Marneris,I.; Bajon, E.; Bonati, R.; Sandberg, J.; Roser, T.; Tsoupas, N.

    2009-05-04

    Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.

  7. High-power, high-efficiency FELs

    Sessler, A.M.

    1989-04-01

    High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

  8. High voltage power network construction

    Harker, Keith

    2018-01-01

    This book examines the key requirements, considerations, complexities and constraints relevant to the task of high voltage power network construction, from design, finance, contracts and project management to installation and commissioning, with the aim of providing an overview of the holistic end to end construction task in a single volume.

  9. A high current, short pulse electron source for wakefield accelerators

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed

  10. High Temperature, High Power Piezoelectric Composite Transducers

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  11. High Power Electron Accelerator Prototype

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  12. Stochastic Dynamic AC Optimal Power Flow Based on a Multivariate Short-Term Wind Power Scenario Forecasting Model

    Wenlei Bai

    2017-12-01

    Full Text Available The deterministic methods generally used to solve DC optimal power flow (OPF do not fully capture the uncertainty information in wind power, and thus their solutions could be suboptimal. However, the stochastic dynamic AC OPF problem can be used to find an optimal solution by fully capturing the uncertainty information of wind power. That uncertainty information of future wind power can be well represented by the short-term future wind power scenarios that are forecasted using the generalized dynamic factor model (GDFM—a novel multivariate statistical wind power forecasting model. Furthermore, the GDFM can accurately represent the spatial and temporal correlations among wind farms through the multivariate stochastic process. Fully capturing the uncertainty information in the spatially and temporally correlated GDFM scenarios can lead to a better AC OPF solution under a high penetration level of wind power. Since the GDFM is a factor analysis based model, the computational time can also be reduced. In order to further reduce the computational time, a modified artificial bee colony (ABC algorithm is used to solve the AC OPF problem based on the GDFM forecasting scenarios. Using the modified ABC algorithm based on the GDFM forecasting scenarios has resulted in better AC OPF’ solutions on an IEEE 118-bus system at every hour for 24 h.

  13. A Novel Hybrid Model for Short-Term Forecasting in PV Power Generation

    Yuan-Kang Wu

    2014-01-01

    Full Text Available The increasing use of solar power as a source of electricity has led to increased interest in forecasting its power output over short-time horizons. Short-term forecasts are needed for operational planning, switching sources, programming backup, reserve usage, and peak load matching. However, the output of a photovoltaic (PV system is influenced by irradiation, cloud cover, and other weather conditions. These factors make it difficult to conduct short-term PV output forecasting. In this paper, an experimental database of solar power output, solar irradiance, air, and module temperature data has been utilized. It includes data from the Green Energy Office Building in Malaysia, the Taichung Thermal Plant of Taipower, and National Penghu University. Based on the historical PV power and weather data provided in the experiment, all factors that influence photovoltaic-generated energy are discussed. Moreover, five types of forecasting modules were developed and utilized to predict the one-hour-ahead PV output. They include the ARIMA, SVM, ANN, ANFIS, and the combination models using GA algorithm. Forecasting results show the high precision and efficiency of this combination model. Therefore, the proposed model is suitable for ensuring the stable operation of a photovoltaic generation system.

  14. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    Yang, Shan; Tong, Xiangqian

    2016-01-01

    Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverte...

  15. From probabilistic forecasts to statistical scenarios of short-term wind power production

    Pinson, Pierre; Papaefthymiou, George; Klockl, Bernd

    2009-01-01

    on the development of the forecast uncertainty through forecast series. However, this additional information may be paramount for a large class of time-dependent and multistage decision-making problems, e.g. optimal operation of combined wind-storage systems or multiple-market trading with different gate closures......Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with highly valuable information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform....... This issue is addressed here by describing a method that permits the generation of statistical scenarios of short-term wind generation that accounts for both the interdependence structure of prediction errors and the predictive distributions of wind power production. The method is based on the conversion...

  16. Short-Circuit Modeling of a Wind Power Plant: Preprint

    Muljadi, E.; Gevorgian, V.

    2011-03-01

    This paper investigates the short-circuit behavior of a WPP for different types of wind turbines. The short-circuit behavior will be presented. Both the simplified models and detailed models are used in the simulations and both symmetrical faults and unsymmetrical faults are discussed.

  17. High-gradient electron accelerator powered by a relativisitic klystron

    Allen, M.A.; Boyd, J.K.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Haimson, J.; Hoag, H.A.; Hopkins, D.B.; Houck, T.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Mecklenburg, B.; Miller, R.H.; Ruth, R.D.; Ryne, R.D.; Sessler, A.M.; Vlieks, A.E.; Wang, J.W.; Westenskow, G.A.; Yu, S.S.

    1989-01-01

    We have used relativistic klystron technology to extract 290 MW of peak power at 11.4 GHz from an induction linac beam, and to power a short 11.4-GHz high-gradient accelerator. We have measured rf phase stability, field emission, and the momentum spectrum of an accelerated electron beam. An average accelerating gradient of 84 MV/m has been achieved with 80 MW of relativistic klystron power

  18. High average power solid state laser power conditioning system

    Steinkraus, R.F.

    1987-01-01

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers

  19. Short-Term Wind Power Forecasting Using the Enhanced Particle Swarm Optimization Based Hybrid Method

    Wen-Yeau Chang

    2013-09-01

    Full Text Available High penetration of wind power in the electricity system provides many challenges to power system operators, mainly due to the unpredictability and variability of wind power generation. Although wind energy may not be dispatched, an accurate forecasting method of wind speed and power generation can help power system operators reduce the risk of an unreliable electricity supply. This paper proposes an enhanced particle swarm optimization (EPSO based hybrid forecasting method for short-term wind power forecasting. The hybrid forecasting method combines the persistence method, the back propagation neural network, and the radial basis function (RBF neural network. The EPSO algorithm is employed to optimize the weight coefficients in the hybrid forecasting method. To demonstrate the effectiveness of the proposed method, the method is tested on the practical information of wind power generation of a wind energy conversion system (WECS installed on the Taichung coast of Taiwan. Comparisons of forecasting performance are made with the individual forecasting methods. Good agreements between the realistic values and forecasting values are obtained; the test results show the proposed forecasting method is accurate and reliable.

  20. Power profiles and short-term visual performance of soft contact lenses.

    Papas, Eric; Dahms, Anne; Carnt, Nicole; Tahhan, Nina; Ehrmann, Klaus

    2009-04-01

    To investigate the manner in which contemporary soft contact lenses differ in the distribution of optical power within their optic zones and establish if these variations affect the vision of wearers or the prescribing procedure for back vertex power (BVP). By using a Visionix VC 2001 contact lens power analyzer, power profiles were measured across the optic zones of the following contemporary contact lenses ACUVUE 2, ACUVUE ADVANCE, O2OPTIX, NIGHT & DAY and PureVision. Single BVP measures were obtained using a Nikon projection lensometer. Visual performance was assessed in 28 masked subjects who wore each lens type in random order. Measurements taken were high and low contrast visual acuity in normal illumination (250 Cd/m), high contrast acuity in reduced illumination (5 Cd/m), subjective visual quality using a numerical rating scale, and visual satisfaction rating using a Likert scale. Marked differences in the distribution of optical power across the optic zone were evident among the lens types. No significant differences were found for any of the visual performance variables (p > 0.05, analysis of variance with repeated measures and Friedman test). Variations in power profile between contemporary soft lens types exist but do not, in general, result in measurable visual performance differences in the short term, nor do they substantially influence the BVP required for optimal correction.

  1. High power microwave source development

    Benford, James N.; Miller, Gabriel; Potter, Seth; Ashby, Steve; Smith, Richard R.

    1995-05-01

    The requirements of this project have been to: (1) improve and expand the sources available in the facility for testing purposes and (2) perform specific tasks under direction of the Defense Nuclear Agency about the applications of high power microwaves (HPM). In this project the HPM application was power beaming. The requirements of this program were met in the following way: (1) We demonstrated that a compact linear induction accelerator can drive HPM sources at repetition rates in excess of 100 HZ at peak microwave powers of a GW. This was done for the relativistic magnetron. Since the conclusion of this contract such specifications have also been demonstrated for the relativistic klystron under Ballistic Missile Defense Organization funding. (2) We demonstrated an L band relativistic magnetron. This device has been used both on our single pulse machines, CAMEL and CAMEL X, and the repetitive system CLIA. (3) We demonstrated that phase locking of sources together in large numbers is a feasible technology and showed the generation of multigigawatt S-band radiation in an array of relativistic magnetrons.

  2. Short-Term Wind Speed Forecasting for Power System Operations

    Zhu, Xinxin; Genton, Marc G.

    2012-01-01

    some statistical short-term wind speed forecasting models, including traditional time series approaches and more advanced space-time statistical models. It also discusses the evaluation of forecast accuracy, in particular, the need for realistic loss

  3. Investigation on the Short Circuit Safe Operation Area of SiC MOSFET Power Modules

    Reigosa, Paula Diaz; Luo, Haoze; Iannuzzo, Francesco

    2016-01-01

    This paper gives a better insight of the short circuit capability of state-of-the-art SiC MOSFET power modules rated at 1.2 kV by highlighting the physical limits under different operating conditions. Two different failure mechanisms have been identified, both reducing the short-circuit capability...... of SiC power modules in respect to discrete SiC devices. Based on such failure mechanisms, two short circuit criteria (i.e., short circuit current-based criterion and gate voltage-based criterion) are proposed in order to ensure their robustness under short-circuit conditions. A Safe Operation Area (SOA...

  4. A Short-Circuit Safe Operation Area Identification Criterion for SiC MOSFET Power Modules

    Reigosa, Paula Diaz; Iannuzzo, Francesco; Luo, Haoze

    2017-01-01

    This paper proposes a new method for the investigation of the short-circuit safe operation area (SCSOA) of state-of-the-art SiC MOSFET power modules rated at 1.2 kV based on the variations in SiC MOSFET electrical parameters (e.g., short-circuit current and gate–source voltage). According...... to the experimental results, two different failure mechanisms have been identified, both reducing the short-circuit capability of SiC power modules with respect to discrete SiC devices. Based on such failure mechanisms, two short-circuit safety criteria have been formulated: 1) the short-circuit...

  5. Operation of Power Grids with High Penetration of Wind Power

    Al-Awami, Ali Taleb

    The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

  6. The Simulation Computer Based Learning (SCBL) for Short Circuit Multi Machine Power System Analysis

    Rahmaniar; Putri, Maharani

    2018-03-01

    Strengthening Competitiveness of human resources become the reply of college as a conductor of high fomal education. Electrical Engineering Program UNPAB (Prodi TE UNPAB) as one of the department of electrical engineering that manages the field of electrical engineering expertise has a very important part in preparing human resources (HR), Which is required by where graduates are produced by DE UNPAB, Is expected to be able to compete globally, especially related to the implementation of Asean Economic Community (AEC) which requires the active participation of graduates with competence and quality of human resource competitiveness. Preparation of HR formation Competitive is done with the various strategies contained in the Seven (7) Higher Education Standard, one part of which is the implementation of teaching and learning process in Electrical system analysis with short circuit analysis (SCA) This course is a course The core of which is the basis for the competencies of other subjects in the advanced semester at Development of Computer Based Learning model (CBL) is done in the learning of interference analysis of multi-machine short circuit which includes: (a) Short-circuit One phase, (B) Two-phase Short Circuit Disruption, (c) Ground Short Circuit Disruption, (d) Short Circuit Disruption One Ground Floor Development of CBL learning model for Electrical System Analysis course provides space for students to be more active In learning in solving complex (complicated) problems, so it is thrilling Ilkan flexibility of student learning how to actively solve the problem of short-circuit analysis and to form the active participation of students in learning (Student Center Learning, in the course of electrical power system analysis.

  7. A Comprehensive Investigation on the Short Circuit Performance of MW-level IGBT Power Modules

    Wu, Rui; Reigosa, Paula Diaz; Iannuzzo, Francesco

    2015-01-01

    This paper investigates the short circuit performance of commercial 1.7 kV / 1 kA IGBT power modules by means of a 6 kA Non-Destructive-Tester. A mismatched current distribution among the parallel chips has been observed, which can reduce the short circuit capability of the IGBT power module unde...... short circuit conditions. Further Spice simulations reveal that the stray parameters inside the module play an important role in contributing to such a phenomenon....

  8. Ultra-Short-Term Wind Power Prediction Using a Hybrid Model

    Mohammed, E.; Wang, S.; Yu, J.

    2017-05-01

    This paper aims to develop and apply a hybrid model of two data analytical methods, multiple linear regressions and least square (MLR&LS), for ultra-short-term wind power prediction (WPP), for example taking, Northeast China electricity demand. The data was obtained from the historical records of wind power from an offshore region, and from a wind farm of the wind power plant in the areas. The WPP achieved in two stages: first, the ratios of wind power were forecasted using the proposed hybrid method, and then the transformation of these ratios of wind power to obtain forecasted values. The hybrid model combines the persistence methods, MLR and LS. The proposed method included two prediction types, multi-point prediction and single-point prediction. WPP is tested by applying different models such as autoregressive moving average (ARMA), autoregressive integrated moving average (ARIMA) and artificial neural network (ANN). By comparing results of the above models, the validity of the proposed hybrid model is confirmed in terms of error and correlation coefficient. Comparison of results confirmed that the proposed method works effectively. Additional, forecasting errors were also computed and compared, to improve understanding of how to depict highly variable WPP and the correlations between actual and predicted wind power.

  9. Introduction to nanotechnology: a short course for high school students

    Markin, Alexey V.

    2016-04-01

    This report devoted to presenting results of development and implementation of a short course (4 hours) entitled "Introduction to Nanotechnology" that was specially designed for familiarizing high school students with nanomaterials and nanotechnology. The course contains introduction to nanotechnology, essential definitions, short overview of history, descriptions for various examples of nanomaterials and their classifications, performing demonstration experiments. All these parts of the course are briefly analyzed from pedagogical effectiveness point of view. Finally, results of course testing, problems and perspectives of nano-oriented education at high school are also discussed shortly.

  10. Short term braking capability during power interruptions for integrated matrix converter

    Klumpner, Christian; Blaabjerg, Frede

    2004-01-01

    attractive. Sinusoidal input currents and bi-directional power flow are other advantages of the matrix converter, but it is less immune to power grid disturbances compared to a standard ASD. In hoisting applications, short-term braking capability during a power outage is needed until the mechanical brake...... engages or to perform more effective a combined braking. This paper proposes a new method to provide short-term braking capability during a power outage for matrix converters. A braking chopper is needed in the clamp circuit, which allows for a drastically reduction of the capacitor size. The power flow...

  11. Short term Braking Capability during Power Interruptions for Integrated Matrix Converter-Motor Drives

    Klumpner, Christian; Blaabjerg, Frede

    2002-01-01

    attractive. Sinusoidal input currents and bi-directional power flow are other advantages of the matrix converter but it is less immune to power grid disturbances compared to a standard ASD. In hoisting applications, short-term braking capability during a power outage is needed until the mechanical brake...... engages or to perform more effective a combined braking.This paper proposes a new method to provide short-term braking capability during a power outage for matrix converters. A braking chopper is needed in the clamp circuit, which allows for a drastically reduction of the capacitor size. The power flow...

  12. The role of short-time intensity and envelope power for speech intelligibility and psychoacoustic masking.

    Biberger, Thomas; Ewert, Stephan D

    2017-08-01

    The generalized power spectrum model [GPSM; Biberger and Ewert (2016). J. Acoust. Soc. Am. 140, 1023-1038], combining the "classical" concept of the power-spectrum model (PSM) and the envelope power spectrum-model (EPSM), was demonstrated to account for several psychoacoustic and speech intelligibility (SI) experiments. The PSM path of the model uses long-time power signal-to-noise ratios (SNRs), while the EPSM path uses short-time envelope power SNRs. A systematic comparison of existing SI models for several spectro-temporal manipulations of speech maskers and gender combinations of target and masker speakers [Schubotz et al. (2016). J. Acoust. Soc. Am. 140, 524-540] showed the importance of short-time power features. Conversely, Jørgensen et al. [(2013). J. Acoust. Soc. Am. 134, 436-446] demonstrated a higher predictive power of short-time envelope power SNRs than power SNRs using reverberation and spectral subtraction. Here the GPSM was extended to utilize short-time power SNRs and was shown to account for all psychoacoustic and SI data of the three mentioned studies. The best processing strategy was to exclusively use either power or envelope-power SNRs, depending on the experimental task. By analyzing both domains, the suggested model might provide a useful tool for clarifying the contribution of amplitude modulation masking and energetic masking.

  13. Optics assembly for high power laser tools

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  14. Overview on the high power excimer laser technology

    Liu, Jingru

    2013-05-01

    High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

  15. Short-Term Photovoltaic Power Generation Forecasting Based on Multivariable Grey Theory Model with Parameter Optimization

    Zhifeng Zhong

    2017-01-01

    Full Text Available Owing to the environment, temperature, and so forth, photovoltaic power generation volume is always fluctuating and subsequently impacts power grid planning and operation seriously. Therefore, it is of great importance to make accurate prediction of the power generation of photovoltaic (PV system in advance. In order to improve the prediction accuracy, in this paper, a novel particle swarm optimization algorithm based multivariable grey theory model is proposed for short-term photovoltaic power generation volume forecasting. It is highlighted that, by integrating particle swarm optimization algorithm, the prediction accuracy of grey theory model is expected to be highly improved. In addition, large amounts of real data from two separate power stations in China are being employed for model verification. The experimental results indicate that, compared with the conventional grey model, the mean relative error in the proposed model has been reduced from 7.14% to 3.53%. The real practice demonstrates that the proposed optimization model outperforms the conventional grey model from both theoretical and practical perspectives.

  16. Ultra-low-power short-range radios

    Chandrakasan, Anantha

    2015-01-01

    This book explores the design of ultra-low-power radio-frequency integrated circuits (RFICs), with communication distances ranging from a few centimeters to a few meters. Such radios have unique challenges compared to longer-range, higher-powered systems. As a result, many different applications are covered, ranging from body-area networks to transcutaneous implant communications and Internet-of-Things devices. A mix of introductory and cutting-edge design techniques and architectures which facilitate each of these applications are discussed in detail. Specifically, this book covers:.

  17. Very-short-term wind power probabilistic forecasts by sparse vector autoregression

    Dowell, Jethro; Pinson, Pierre

    2016-01-01

    A spatio-temporal method for producing very-shortterm parametric probabilistic wind power forecasts at a large number of locations is presented. Smart grids containing tens, or hundreds, of wind generators require skilled very-short-term forecasts to operate effectively, and spatial information...... is highly desirable. In addition, probabilistic forecasts are widely regarded as necessary for optimal power system management as they quantify the uncertainty associated with point forecasts. Here we work within a parametric framework based on the logit-normal distribution and forecast its parameters....... The location parameter for multiple wind farms is modelled as a vector-valued spatiotemporal process, and the scale parameter is tracked by modified exponential smoothing. A state-of-the-art technique for fitting sparse vector autoregressive models is employed to model the location parameter and demonstrates...

  18. Test of a High Power Target Design

    2002-01-01

    %IS343 :\\\\ \\\\ A high power tantalum disc-foil target (RIST) has been developed for the proposed radioactive beam facility, SIRIUS, at the Rutherford Appleton Laboratory. The yield and release characteristics of the RIST target design have been measured at ISOLDE. The results indicate that the yields are at least as good as the best ISOLDE roll-foil targets and that the release curves are significantly faster in most cases. Both targets use 20 -25 $\\mu$m thick foils, but in a different internal geometry.\\\\ \\\\Investigations have continued at ISOLDE with targets having different foil thickness and internal geometries in an attempt to understand the release mechanisms and in particular to maximise the yield of short lived isotopes. A theoretical model has been developed which fits the release curves and gives physical values of the diffusion constants.\\\\ \\\\The latest target is constructed from 2 $\\mu$m thick tantalum foils (mass only 10 mg) and shows very short release times. The yield of $^{11}$Li (half-life of ...

  19. Short Term Energy Storage for Grid Support in Wind Power Applications

    Stroe, Daniel Ioan; Stan, Ana-Irina; Diosi, Robert

    2012-01-01

    The penetration of wind power into the power system has been increasing in the recent years. Therefore, a lot of concerns related to the reliable operation of the power system have been addressed. An attractive solution to minimize the limitations faced by the wind power grid integration, and thus...... to increase the power system stability and the energy quality, is to integrate energy storage devices into wind power plants. This paper gives an overview of the state-of-the-art short-term energy storage devices and presents several applications which can be provided by the energy storage device - wind power...

  20. high power facto high power factor high power factor hybrid rectifier

    eobe

    increase in the number of electrical loads that some kind of ... components in the AC power system. Thus, suppl ... al output power; assuring reliability in ... distribution systems. This can be ...... Thesis- Califonia Institute of Technology, Capitulo.

  1. Short Remarks on the Principle of Separation of Powers

    Ionela Despa

    2012-05-01

    Full Text Available The principle of separation of powers, as a basic principle of a real democratic political system,concerns that state activities, powers are separated by the fact that they take place separately, distinct fromone another, each with its specific, but in the social polical reality it can be seen that there are linksbetween public authorities in terms of organizational and functional, namely cooperation and mutualdeterminations. In terms of organization, the link is given by the fact that some state bodies involved in theformation of other, and the functional aspect concerns the connection of collaborations: theconstitutionality of laws passed by Parliament is controlled by the Constitutional Court or Governmentactivity can be examined by Parliament. The modern form of the principle of separation of powers requiresautonomous public authorities, sharing their incumbent functions, establishment of means of cooperationand mutual control, all in the ambience of a genuine and real autonomy. So a state cannot work unless thelaw adopted by thelegislature is applied to urge the executive and the judiciary by the executive contestcarries out its decisions. This cooperation should be accompanied by a power control, equipped with legaland institutional means that will not neutralize eachother.

  2. High power ubitron-klystron

    Balkcum, A.J.; McDermott, D.B.; Luhmann, N.C. Jr.

    1997-01-01

    A coaxial ubitron is being considered as the rf driver for the Next Linear Collider (NLC). Prior simulation of a traveling-wave ubitron using a self-consistent code found that 200 MW of power and 53 dB of gain could be achieved with 37% efficiency. In a ubiron-klystron, a series of cavities are used to obtain an even tighter electron bunch for higher efficiency. A small-signal theory of the ubitron-klystron shows that gain scales with the square of the cavity separation distance. A linear stability theory has also been developed. Verification of the stability theory has been achieved using the 2-12-D PIC code, MAGIC, and the particle-tracing code. Saturation characteristics of the amplifier will be presented using both MAGIC and a simpler self-consistent slow-timescale code currently under development. The ubitron can also operate as a compact, highly efficient oscillator. Cavities only two wiggler periods in length have yielded up to 40% rf conversion efficiency in simulation. An initial oscillator design for directed energy applications will also be presented

  3. Simplified High-Power Inverter

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  4. Short-Term Forecasting of Loads and Wind Power for Latvian Power System: Accuracy and Capacity of the Developed Tools

    Radziukynas, V.; Klementavičius, A.

    2016-04-01

    The paper analyses the performance results of the recently developed short-term forecasting suit for the Latvian power system. The system load and wind power are forecasted using ANN and ARIMA models, respectively, and the forecasting accuracy is evaluated in terms of errors, mean absolute errors and mean absolute percentage errors. The investigation of influence of additional input variables on load forecasting errors is performed. The interplay of hourly loads and wind power forecasting errors is also evaluated for the Latvian power system with historical loads (the year 2011) and planned wind power capacities (the year 2023).

  5. Short-Term Forecasting of Loads and Wind Power for Latvian Power System: Accuracy and Capacity of the Developed Tools

    Radziukynas V.

    2016-04-01

    Full Text Available The paper analyses the performance results of the recently developed short-term forecasting suit for the Latvian power system. The system load and wind power are forecasted using ANN and ARIMA models, respectively, and the forecasting accuracy is evaluated in terms of errors, mean absolute errors and mean absolute percentage errors. The investigation of influence of additional input variables on load forecasting errors is performed. The interplay of hourly loads and wind power forecasting errors is also evaluated for the Latvian power system with historical loads (the year 2011 and planned wind power capacities (the year 2023.

  6. Review of Power System Stability with High Wind Power Penetration

    Hu, Rui; Hu, Weihao; Chen, Zhe

    2015-01-01

    analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

  7. Production of ozone using nanosecond short pulsed power

    Shimomura, N.; Wakimoto, M.; Togo, H.; Namihira, Takao; Akiyama, Hidenori; ナミヒラ, タカオ; アキヤマ, ヒデノリ; 浪平, 隆男; 秋山, 秀典

    2003-01-01

    Production of ozone is one of the most typical industrial and commercial applications of electrical discharge. The demand of ozone will be increasing for wholesome and environment-friendly sterilizations. The production of ozone using the pulsed power discharge will apply electron accelerations around the head of streamer discharge. The breakdowns in reactor, however, often limit the efficient production. The pulse shape should be controlled for dimension of the reactor. On the other hand, th...

  8. Highly-stabilized power supply for synchrotron accelerators. High speed, low ripple power supply

    Sato, Kenji [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Kumada, Masayuki; Fukami, Kenji; Koseki, Shoichiro; Kubo, Hiroshi; Kanazawa, Toru

    1997-02-01

    In synchrotron accelerators, in order to utilize high energy beam effectively, those are operated by repeating acceleration and taking-out at short period. In order to accelerate by maintaining beam track stable, the tracking performance with the error less than 10{sup -3} in the follow-up of current is required for the power supply. Further, in order to maintain the intensity and uniformity of beam when it is taken out, very low ripple is required for output current. The power supply having such characteristics has been developed, and applied to the HIMAC and the SPring-8. As the examples of the application of synchrotrons, the accelerators for medical treatment and the generation of synchrotron radiation are described. As to the power supply for the deflection magnets and quadrupole magnets of synchrotron accelerators, the specifications of the main power supply, the method of reducing ripple, the method of improving tracking, and active filter control are reported. As to the test results, the measurement of current ripple and tracking error is shown. The lowering of ripple was enabled by common mode filter and the symmetrical connection of electromagnets, and high speed response was realized by the compensation for delay with active filter. (K.I.)

  9. Electronic DC transformer with high power density

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  10. Approximative calculation of transient short-circuit currents in power-systems

    Heuck, K; Rosenberger, R; Dettmann, K D; Kegel, R

    1986-08-01

    The paper shows that it is approximatively possible to calculate the transient short-circuit currents for symmetrical and asymmetrical faults in power-systems. For that purpose a simple equivalent network is found. Its error of approximation is small. For the important maximum short-circuit current limits of error are pointed out compared to VDE 0102.

  11. Thirteen years test experience with short-circuit withstand capability of large power transformers

    Smeets, R.P.P.; Paske, te L.H.; Leufkens, P.P.; Fogelberg, T.

    2009-01-01

    The ability to withstand a short circuit is recognised more and more as an essential characteristic of power transformers. IEC and IEEE Standards, as well as other national standards specify short-circuit testing and how to check the withstand capability. Unfortunately, however, there is extensive

  12. Fourteen years of test experience with short-circuit withstand capability of large power transformers

    Smeets, R.P.P.; Paske, te L.H.

    2010-01-01

    Experience is reported of short-circuit testing of large power transformers during the past 14 years by KEMA in the Netherlands. In total, 119 transformers > 25 MVA participated in the survey. KEMA shows that at initial access to standard IEC short-circuit tests, 28% failed initially in a wide range

  13. Sixteen years of test experiences with short-circuit withstand capability of large power transformers

    Smeets, R.P.P.; Paske, te L.H.

    2012-01-01

    Experience is reported of short-circuit testing of large power transformers during the past 16 years by KEMA in the Netherlands. In total, 174 transformers > 25 MVA participated in the survey. KEMA shows that at initial access to standard IEC short-circuit tests, 24% failed initially in a wide range

  14. High power CW linac in PNC

    Toyama, S.; Wang, Y.L.; Emoto, T.

    1994-01-01

    Power Reactor and Nuclear Fuel Development Corporation (PNC) is developing a high power electron linac for various applications. The electron beam is accelerated in CW operation to get maximum beam current of 100 mA and energy of 10 MeV. Crucial components such as a high power L-band klystron and a high power traveling wave resonant ring (TWRR) accelerator guides were designed and manufactured and their performance were examined. These design and results from the recent high power RF tests were described in this paper. (author)

  15. High Power Density Power Electronic Converters for Large Wind Turbines

    Senturk, Osman Selcuk

    . For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability......In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability...

  16. High Power Fiber Laser Test Bed

    Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

  17. Ensemble Nonlinear Autoregressive Exogenous Artificial Neural Networks for Short-Term Wind Speed and Power Forecasting.

    Men, Zhongxian; Yee, Eugene; Lien, Fue-Sang; Yang, Zhiling; Liu, Yongqian

    2014-01-01

    Short-term wind speed and wind power forecasts (for a 72 h period) are obtained using a nonlinear autoregressive exogenous artificial neural network (ANN) methodology which incorporates either numerical weather prediction or high-resolution computational fluid dynamics wind field information as an exogenous input. An ensemble approach is used to combine the predictions from many candidate ANNs in order to provide improved forecasts for wind speed and power, along with the associated uncertainties in these forecasts. More specifically, the ensemble ANN is used to quantify the uncertainties arising from the network weight initialization and from the unknown structure of the ANN. All members forming the ensemble of neural networks were trained using an efficient particle swarm optimization algorithm. The results of the proposed methodology are validated using wind speed and wind power data obtained from an operational wind farm located in Northern China. The assessment demonstrates that this methodology for wind speed and power forecasting generally provides an improvement in predictive skills when compared to the practice of using an "optimal" weight vector from a single ANN while providing additional information in the form of prediction uncertainty bounds.

  18. Allocation of synchronous condensers for restoration of system short-circuit power

    Marrazi, Emanuel; Yang, Guangya; Weinreich-Jensen, Peter

    2017-01-01

    Modern power systems, employing an increasing number of converter-based renewable energy sources (RES) and decreasing the usage of conventional power plants, are leading to lower levels of short-circuit power and rotational inertia. A solution to this is the employment of synchronous condensers...... in the grid, in order to provide sufficient short-circuit power. This results in the increase of the short-circuit ratio (SCR) at transmission system bus-bars serving as points of interconnection (POI) to renewable generation. Evaluation of the required capacity and grid-location of the synchronous condensers...... by renewable generation. Total cost of synchronous condenser installations in the system is minimized and the SCRs at the POIs of central renewable power plants are strengthened. The method has potential for application on larger grids, aiding grid-integration of RES....

  19. Short-term wind power prediction based on LSSVM–GSA model

    Yuan, Xiaohui; Chen, Chen; Yuan, Yanbin; Huang, Yuehua; Tan, Qingxiong

    2015-01-01

    Highlights: • A hybrid model is developed for short-term wind power prediction. • The model is based on LSSVM and gravitational search algorithm. • Gravitational search algorithm is used to optimize parameters of LSSVM. • Effect of different kernel function of LSSVM on wind power prediction is discussed. • Comparative studies show that prediction accuracy of wind power is improved. - Abstract: Wind power forecasting can improve the economical and technical integration of wind energy into the existing electricity grid. Due to its intermittency and randomness, it is hard to forecast wind power accurately. For the purpose of utilizing wind power to the utmost extent, it is very important to make an accurate prediction of the output power of a wind farm under the premise of guaranteeing the security and the stability of the operation of the power system. In this paper, a hybrid model (LSSVM–GSA) based on the least squares support vector machine (LSSVM) and gravitational search algorithm (GSA) is proposed to forecast the short-term wind power. As the kernel function and the related parameters of the LSSVM have a great influence on the performance of the prediction model, the paper establishes LSSVM model based on different kernel functions for short-term wind power prediction. And then an optimal kernel function is determined and the parameters of the LSSVM model are optimized by using GSA. Compared with the Back Propagation (BP) neural network and support vector machine (SVM) model, the simulation results show that the hybrid LSSVM–GSA model based on exponential radial basis kernel function and GSA has higher accuracy for short-term wind power prediction. Therefore, the proposed LSSVM–GSA is a better model for short-term wind power prediction

  20. High Power Wireless Transfer : For Charging High Power Batteries

    Gill, Himmat

    2017-01-01

    Wireless power transfer (WPT) is developing with emerging of new technologies that has made it possible to transfer electricity over certain distances without any physical contact, offering significant benefits to modern automation systems, medical applications, consumer electronic, and especially in electric vehicle systems. The goal of this study is to provide a brief review of existing compensation topologies for the loosely coupled transformer. The technique used to simulate a co...

  1. Non-Destructive Investigation on Short Circuit Capability of Wind-Turbine-Scale IGBT Power Modules

    Wu, Rui; Iannuzzo, Francesco; Wang, Huai

    2014-01-01

    This paper presents a comprehensive investigation on the short circuit capability of wind-turbine-scale IGBT power modules by means of a 6 kA/1.1 kV non-destructive testing system. A Field Programmable Gate Array (FPGA) supervising unit is adpoted to achieve an accurate time control for short...... circuit test, which enables to define the driving signals with an accuracy of 10 ns. Thanks to the capability and the effectiveness of the constructed setup, oscillations appearing during short circuits of the new-generation 1.7 kV/1 kA IGBT power modules have been evidenced and characterized under...

  2. High Power laser power conditioning system new discharge circuit research

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  3. Developing a Local Neurofuzzy Model for Short-Term Wind Power Forecasting

    E. Faghihnia

    2014-01-01

    Full Text Available Large scale integration of wind generation capacity into power systems introduces operational challenges due to wind power uncertainty and variability. Therefore, accurate wind power forecast is important for reliable and economic operation of the power systems. Complexities and nonlinearities exhibited by wind power time series necessitate use of elaborative and sophisticated approaches for wind power forecasting. In this paper, a local neurofuzzy (LNF approach, trained by the polynomial model tree (POLYMOT learning algorithm, is proposed for short-term wind power forecasting. The LNF approach is constructed based on the contribution of local polynomial models which can efficiently model wind power generation. Data from Sotavento wind farm in Spain was used to validate the proposed LNF approach. Comparison between performance of the proposed approach and several recently published approaches illustrates capability of the LNF model for accurate wind power forecasting.

  4. Superconducting high frequency high power resonators

    Hobbis, C.; Vardiman, R.; Weinman, L.

    1974-01-01

    A niobium superconducting quarter-wave helical resonator has been designed and built. The resonator has been electron-beam welded and electropolished to produce a smooth flaw-free surface. This has been followed by an anodization to produce a 1000 A layer of Nb 2 0 5 . At the resonant frequency of approximately 15 MHz the unloaded Q was approximately equal to 4.6x10 6 with minimal dielectric support. With the resonator open to the helium bath to provide cooling, and rigidly supported by a teflon cylinder, 350 V of power were transferred at a doubly loaded Q of 3500. The extrapolation of the results to a Qsub(DL) of 1000 meet the power handling criteria of one kilowatt for the intended application. (author)

  5. Allocation of synchronous condensers for restoration of system short-circuit power

    Marrazi, Emanuel; Yang, Guangya; Weinreich-Jensen, Peter

    2017-01-01

    Modern power systems, employing an increasing number of converter-based renewable energy sources (RES) and decreasing the usage of conventional power plants, are leading to lower levels of short-circuit power and rotational inertia. A solution to this is the employment of synchronous condensers...... in the grid, in order to provide sufficient short-circuit power. This results in the increase of the short-circuit ratio (SCR) at transmission system bus-bars serving as points of interconnection (POI) to renewable generation. Evaluation of the required capacity and grid-location of the synchronous condensers......, isinherently a mixed integer non-linear optimization problem, which could not be done on manual basis considering each type of machine and all bus-bars. This study therefore proposes a method of optimal allocation of synchronous condensers in a hypothetic future scenario of a transmission system fed...

  6. Application of a High-Power Reversible Converter in a Hybrid Traction Power Supply System

    Gang Zhang

    2017-03-01

    Full Text Available A high-power reversible converter can achieve a variety of functions, such as recovering regenerative braking energy, expanding traction power capacity, and improving an alternating current (AC grid power factor. A new hybrid traction power supply scheme, which consists of a high-power reversible converter and two 12-pulse diode rectifiers, is proposed. A droop control method based on load current feed-forward is adopted to realize the load distribution between the reversible converter and the existing 12-pulse diode rectifiers. The direct current (DC short-circuit characteristics of the reversible converter is studied, then the relationship between the peak fault current and the circuit parameters is obtained from theoretical calculations and validated by computer simulation. The first two sets of 2 MW reversible converters have been successfully applied in Beijing Metro Line 10, the proposed hybrid application scheme and coordinated control strategy are verified, and 11.15% of average energy-savings is reached.

  7. High voltage short plus generation based on avalanche circuit

    Hu Yuanfeng; Yu Xiaoqi

    2006-01-01

    Simulate the avalanche circuit in series with PSPICE module, design the high voltage short plus generation circuit by avalanche transistor in series for the sweep deflection circuit of streak camera. The output voltage ranges 1.2 KV into 50 ohm load. The rise time of the circuit is less than 3 ns. (authors)

  8. High-intensity exercise and recovery during short-term ...

    Objective. To determine the effect of short-term creatine supplementation plus a protein-carbohydrate formula on high-intensity exercise performance and recovery. Design. A repeated-measures, experimental study, employing a randomised, double-blind, placebo-controlled, group comparison design was used.

  9. PUMA code simulation of recovery power transients after a short shutdown of the Embalse nuclear power plant

    Villar, Javier; Pomerantz, Marcelo E.

    2003-01-01

    A simulation of recovery power transients after a short shutdown on Embalse nuclear power plant equilibrium core with slightly enriched uranium fuel was performed in order to know the response of the reactor under such conditions. Also, comparison against the same event in a natural uranium core were done. No significant restrictions were found in operating with enriched fuel in the conditions of the analyzed event and in fact, slightly differences arose with natural uranium fuels. (author)

  10. Short (

    Telleman, Gerdien; den Hartog, Laurens

    2013-01-01

    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  11. High Power Flex-Propellant Arcjet Performance

    Litchford, Ron J.

    2011-01-01

    A MW-class electrothermal arcjet based on a water-cooled, wall-stabilized, constricted arc discharge configuration was subjected to extensive performance testing using hydrogen and simulated ammonia propellants with the deliberate aim of advancing technology readiness level for potential space propulsion applications. The breadboard design incorporates alternating conductor/insulator wafers to form a discharge barrel enclosure with a 2.5-cm internal bore diameter and an overall length of approximately 1 meter. Swirling propellant flow is introduced into the barrel, and a DC arc discharge mode is established between a backplate tungsten cathode button and a downstream ringanode/ spin-coil assembly. The arc-heated propellant then enters a short mixing plenum and is accelerated through a converging-diverging graphite nozzle. This innovative design configuration differs substantially from conventional arcjet thrusters, in which the throat functions as constrictor and the expansion nozzle serves as the anode, and permits the attainment of an equilibrium sonic throat (EST) condition. During the test program, applied electrical input power was varied between 0.5-1 MW with hydrogen and simulated ammonia flow rates in the range of 4-12 g/s and 15-35 g/s, respectively. The ranges of investigated specific input energy therefore fell between 50-250 MJ/kg for hydrogen and 10-60 MJ/kg for ammonia. In both cases, observed arc efficiencies were between 40-60 percent as determined via a simple heat balance method based on electrical input power and coolant water calorimeter measurements. These experimental results were found to be in excellent agreement with theoretical chemical equilibrium predictions, thereby validating the EST assumption and enabling the utilization of standard TDK nozzle expansion analyses to reliably infer baseline thruster performance characteristics. Inferred specific impulse performance accounting for recombination kinetics during the expansion process

  12. High-Temperature-Short-Time Annealing Process for High-Performance Large-Area Perovskite Solar Cells.

    Kim, Minjin; Kim, Gi-Hwan; Oh, Kyoung Suk; Jo, Yimhyun; Yoon, Hyun; Kim, Ka-Hyun; Lee, Heon; Kim, Jin Young; Kim, Dong Suk

    2017-06-27

    Organic-inorganic hybrid metal halide perovskite solar cells (PSCs) are attracting tremendous research interest due to their high solar-to-electric power conversion efficiency with a high possibility of cost-effective fabrication and certified power conversion efficiency now exceeding 22%. Although many effective methods for their application have been developed over the past decade, their practical transition to large-size devices has been restricted by difficulties in achieving high performance. Here we report on the development of a simple and cost-effective production method with high-temperature and short-time annealing processing to obtain uniform, smooth, and large-size grain domains of perovskite films over large areas. With high-temperature short-time annealing at 400 °C for 4 s, the perovskite film with an average domain size of 1 μm was obtained, which resulted in fast solvent evaporation. Solar cells fabricated using this processing technique had a maximum power conversion efficiency exceeding 20% over a 0.1 cm 2 active area and 18% over a 1 cm 2 active area. We believe our approach will enable the realization of highly efficient large-area PCSs for practical development with a very simple and short-time procedure. This simple method should lead the field toward the fabrication of uniform large-scale perovskite films, which are necessary for the production of high-efficiency solar cells that may also be applicable to several other material systems for more widespread practical deployment.

  13. Suppressing voltage transients in high voltage power supplies

    Lickel, K.F.; Stonebank, R.

    1979-01-01

    A high voltage power supply for an X-ray tubes includes voltage adjusting means, a high voltage transformer, switch means connected to make and interrupt the primary current of the transformer, and over-voltage suppression means to suppress the voltage transient produced when the current is switched on. In order to reduce the power losses in the suppression means, an impedance is connected in the transformer primary circuit on operation of the switch means and is subsequently short-circuited by a switch controlled by a timer after a period which is automatically adjusted to the duration of the transient overvoltage. (U.K.)

  14. High-power ultrashort fiber laser for solar cells micromachining

    Lecourt, J.-B.; Duterte, C.; Liegeois, F.; Lekime, D.; Hernandez, Y.; Giannone, D.

    2012-02-01

    We report on a high-power ultra-short fiber laser for thin film solar cells micromachining. The laser is based on Chirped Pulse Amplification (CPA) scheme. The pulses are stretched to hundreds of picoseconds prior to amplification and can be compressed down to picosecond at high energy. The repetition rate is adjustable from 100 kHz to 1 MHz and the optical average output power is close to 13 W (before compression). The whole setup is fully fibred, except the compressor achieved with bulk gratings, resulting on a compact and reliable solution for cold ablation.

  15. A highly linear power amplifier for WLAN

    Jin Jie; Shi Jia; Ai Baoli; Zhang Xuguang

    2016-01-01

    A three-stage power amplifier (PA) for WLAN application in 2.4-2.5 GHz is presented. The proposed PA employs an adaptive bias circuit to adjust the operating point of the PA to improve the linearity of the PA. Two methods to short the 2nd harmonic circuit are compared in the area of efficiency and gain of the PA. The PA is taped out in the process of 2 μm InGaP/GaAs HBT and is tested by the evaluation board. The measured results show that 31.5 dB power gain and 29.3 dBm P 1dB with an associated 40.4% power added efficiency (PAE) under the single tone stimulus. Up to 26.5 dBm output power can be achieved with an error vector magnitude (EVM) of lower than 3% under the 64QAM/OFDM WLAN stimulus. (paper)

  16. Automated System Tests High-Power MOSFET's

    Huston, Steven W.; Wendt, Isabel O.

    1994-01-01

    Computer-controlled system tests metal-oxide/semiconductor field-effect transistors (MOSFET's) at high voltages and currents. Measures seven parameters characterizing performance of MOSFET, with view toward obtaining early indication MOSFET defective. Use of test system prior to installation of power MOSFET in high-power circuit saves time and money.

  17. High-Capacity Short-Range Optical Communication Links

    Tatarczak, Anna

    Over the last decade, we have observed a tremendous spread of end-user mobile devices. The user base of a mobile application can grow or shrink by millions per day. This situation creates a pressing need for highly scalable server infrastructure; a need nowadays satisfied through cloud computing...... offered by data centers. As the popularity of cloud computing soars, the demand for high-speed, short-range data center links grows. Vertical cavity surface emitting lasers (VCSEL) and multimode fibers (MMF) prove especially well-suited for such scenarios. VCSELs have high modulation bandwidths......, we achieve 10 Gbps over 400 m and then conrm the approach in an optimized system at 25 Gbps over 300 m. The techniques described in this thesis leverage additional degrees of freedom to better utilize the available resources of short-range links. The proposed schemes enable higher speeds and longer...

  18. Short-circuit tests of 1650 and 96 MVA transformers for 1300 MW french nuclear power plants

    Mailhot, M.

    1989-01-01

    Power evacuation and feeding of the auxiliaries directly from the 400 kV grid are sensitive points governing the security of 1300 MW PWR Nuclear Power Plants of the French Program. These two different functions are provided by two specific types of transformers. - Banks of 3 single-phase 550 MVA - 400 kV/20 kV transformers. - Three-phase 96 MVA - 400 kV / 3 x 6.8 kV transformers. These passive elements must have a never failing reliability and assure a continuous service in spite of electric, thermal and mechanical stresses that may occur during the lifetime of the power plant. Dielectric and thermal tests carried out in the manufacturers test floors insure these stresses withstand capabilities of transformers. In France, high short-circuit power for the 400 kV network added to often low impedance voltages for transformers impose on them very high stresses during short-circuits. Calculation and experimentation on scale or partial models are not sufficient to insure short-circuit currents withstand capabilities of transformers. The margin of uncertainty dependent on obligatory extrapolations for this kind of complex systems [steel, magnetic sheets, copper, oil, paper and transformerboard] can be reduced in a significant way only by real scale tests on prototypes. These tests that need both high power and voltage cannot be performed in manufacturers test floors. So, in France they are carried out at the EDF Les Renardieres Laboratory. Following paper deals with SHELL TYPE TRANSFORMERS which, particularly thanks to their interleaved rectangular windings display a great resistance to short-circuit stresses

  19. Powering the High-Luminosity Triplets

    Ballarino, A.; Burnet, J. P.

    The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

  20. High current and high power superconducting rectifiers

    Kate, H.H.J. ten; Bunk, P.B.; Klundert, L.J.M. van de; Britton, R.B.

    1981-01-01

    Results on three experimental superconducting rectifiers are reported. Two of them are 1 kA low frequency flux pumps, one thermally and magnetically switched. The third is a low-current high-frequency magnetically switched rectifier which can use the mains directly. (author)

  1. Load Flow and Short Circuit Analysis of the Class III Power System of HANARO

    Kim, H. K.; Jung, H. S

    2005-12-15

    The planning, design, and operation of electric power system require engineering studies to assist in the evaluation of the system performance, reliability, safety and economics. The Class III power of HANARO supplies power for not only HANARO but also RIPF and IMEF. The starting current of most ac motors is five to ten times normal full load current. The loads of the Class III power are connected in consecutive orders at an interval for 10 seconds to avoid excessive voltage drop. This technical report deals with the load flow study and motor starting study for the Class III power of HANARO using ETAP(Electrical Transient Analyzer Program) to verify the capacity of the diesel generator. Short-circuit studies are done to determine the magnitude of the prospective currents flowing throughout the power system at various time intervals after a fault occurs. Short-circuit studies can be performed at the planning stage in order to help finalize the system layout, determine voltage levels, and size cables, transformers, and conductors. From this study, we verify the short circuit current capacity of air circuit breaker(ACB) and automatic transfer switch(ATS) of the Class III power.

  2. Some observations on stray magnetic fields and power outputs from short-wave diathermy equipment

    Lau, R.W.M.; Dunscombe, P.B.

    1984-04-01

    Recent years have seen increasing interest in the possible hazards arising from the use of nonionizing electromagnetic radiation. Relatively large and potentially hazardous fields are to be found in the vicinity of short-wave and microwave equipment used in physiotherapy departments to produce therapeutic temperature rises. This note reports the results of measurements of the stray magnetic field and power output of a conventional short-wave diathermy unit when applied to tissue-equivalent phantoms. The dependence of these quantities on the variables, i.e. power setting of the unit, capacitor plate size, phantom size and phantom-capacitor plate separation, are discussed.

  3. A short-run solution to the power crisis of Pakistan

    Imran, Muhammad; Amir, Namra

    2015-01-01

    Pakistan is in a deep power crisis since 2008 which the government is trying to control by adding new generation capacity. This strategy, however, will not be helpful in the short-run. The only way, the power crisis can be controlled or mitigated in the short-run, is to efficiently utilize the available resources. Government lacks such a strategy at this point. The paper provides such a strategy by setting up a power sector model with multiple modules of generation, transmission and distribution. The model provides an efficient way of utilizing the available resources and can be used to perform simulations at different stages of the supply-chain. The results of model show that, if the given resources are utilized efficiently, the power generation increases by 3222 GWh or 5 percent of the current output and the revenue increases by $945 million or 12 percent. The extra generated power decrease the cost of power production by 0.52 ¢/KWh cents and reduces the power load-shedding for 2–3 h. These outcomes can significantly relieve the sector and the people of Pakistan. The results of the model have important policy implications on working of the sector and circular debt reduction. - Highlights: • Government needs a new strategy to come out of the power crisis along with adding new power generation. • Because one major reason of current power crisis is the inefficient use of available resources. • Focus of this paper is to provide such a strategy by setting up a power sector supply-chain model. • When resources are utilized efficiently, power generation and revenue increases by 5 and 12 percent respectively. • These outputs decreases cost of power production by 0.52¢/KWh and power load-shedding by 2–3 h.

  4. High power ultrashort pulse lasers

    Perry, M.D.

    1994-01-01

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced

  5. A novel power source for high-precision, highly efficient micro w-EDM

    Chen, Shun-Tong; Chen, Chi-Hung

    2015-01-01

    The study presents the development of a novel power source for high-precision, highly efficient machining of micropart microstructures using micro wire electrical discharge machining (w-EDM). A novel power source based on a pluri resistance–capacitance (pRC) circuit that can generate a high-frequency, high-peak current with a short pulse train is proposed and designed to enhance the performance of micro w-EDM processes. Switching between transistors is precisely controlled in the designed power source to create a high-frequency short-pulse train current. Various microslot cutting tests in both aluminum and copper alloys are conducted. Experimental results demonstrate that the pRC power source creates instant spark erosion resulting in markedly less material for removal, diminishing discharge crater size, and consequently an improved surface finish. A new evaluation approach for spark erosion ability (SEA) to assess the merits of micro EDM power sources is also proposed. In addition to increasing the speed of micro w-EDM by increasing wire feed rates by 1.6 times the original feed rate, the power source is more appropriate for machining micropart microstructures since there is less thermal breaking. Satisfactory cutting of an elaborate miniature hook-shaped structure and a high-aspect ratio microstructure with a squared-pillar array also reveal that the developed pRC power source is effective, and should be very useful in the manufacture of intricate microparts. (paper)

  6. Evolution of Very High Frequency Power Supplies

    Knott, Arnold; Andersen, Toke Meyer; Kamby, Peter

    2013-01-01

    The ongoing demand for smaller and lighter power supplies is driving the motivation to increase the switching frequencies of power converters. Drastic increases however come along with new challenges, namely the increase of switching losses in all components. The application of power circuits used...... in radio frequency transmission equipment helps to overcome those. However those circuits were not designed to meet the same requirements as power converters. This paper summarizes the contributions in recent years in application of very high frequency (VHF) technologies in power electronics, shows results...... of the recent advances and describes the remaining challenges. The presented results include a self-oscillating gate-drive, air core inductor optimizations, an offline LED driver with a power density of 8.9 W/cm3 and a 120 MHz, 9 W DC powered LED driver with 89 % efficiency as well as a bidirectional VHF...

  7. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    Shan Yang

    2016-01-01

    Full Text Available Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverter based distributed generation is proposed. The proposed method let the inverter based distributed generation be equivalent to Iθ bus, which makes it suitable to calculate the power flow of distribution network with a current limited inverter based distributed generation. And the low voltage ride through capability of inverter based distributed generation can be considered as well in this paper. Finally, some tests of power flow and short circuit current calculation are performed on a 33-bus distribution network. The calculated results from the proposed method in this paper are contrasted with those by the traditional method and the simulation method, whose results have verified the effectiveness of the integrated method suggested in this paper.

  8. Predicting High-Power Performance in Professional Cyclists.

    Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

    2017-03-01

    To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

  9. The NASA CSTI High Capacity Power Project

    Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Schmitz, P.; Vandersande, J.

    1992-01-01

    This paper describes the elements of NASA's CSTI High Capacity Power Project which include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timeliness recently developed

  10. Short-term wind power combined forecasting based on error forecast correction

    Liang, Zhengtang; Liang, Jun; Wang, Chengfu; Dong, Xiaoming; Miao, Xiaofeng

    2016-01-01

    Highlights: • The correlation relationships of short-term wind power forecast errors are studied. • The correlation analysis method of the multi-step forecast errors is proposed. • A strategy selecting the input variables for the error forecast models is proposed. • Several novel combined models based on error forecast correction are proposed. • The combined models have improved the short-term wind power forecasting accuracy. - Abstract: With the increasing contribution of wind power to electric power grids, accurate forecasting of short-term wind power has become particularly valuable for wind farm operators, utility operators and customers. The aim of this study is to investigate the interdependence structure of errors in short-term wind power forecasting that is crucial for building error forecast models with regression learning algorithms to correct predictions and improve final forecasting accuracy. In this paper, several novel short-term wind power combined forecasting models based on error forecast correction are proposed in the one-step ahead, continuous and discontinuous multi-step ahead forecasting modes. First, the correlation relationships of forecast errors of the autoregressive model, the persistence method and the support vector machine model in various forecasting modes have been investigated to determine whether the error forecast models can be established by regression learning algorithms. Second, according to the results of the correlation analysis, the range of input variables is defined and an efficient strategy for selecting the input variables for the error forecast models is proposed. Finally, several combined forecasting models are proposed, in which the error forecast models are based on support vector machine/extreme learning machine, and correct the short-term wind power forecast values. The data collected from a wind farm in Hebei Province, China, are selected as a case study to demonstrate the effectiveness of the proposed

  11. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

    2005-01-01

    Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

  12. ACIGA's high optical power test facility

    Ju, L; Aoun, M; Barriga, P

    2004-01-01

    Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ∼10 6 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties

  13. A New Neural Network Approach to Short Term Load Forecasting of Electrical Power Systems

    Farshid Keynia

    2011-03-01

    Full Text Available Short-term load forecast (STLF is an important operational function in both regulated power systems and deregulated open electricity markets. However, STLF is not easy to handle due to the nonlinear and random-like behaviors of system loads, weather conditions, and social and economic environment variations. Despite the research work performed in the area, more accurate and robust STLF methods are still needed due to the importance and complexity of STLF. In this paper, a new neural network approach for STLF is proposed. The proposed neural network has a novel learning algorithm based on a new modified harmony search technique. This learning algorithm can widely search the solution space in various directions, and it can also avoid the overfitting problem, trapping in local minima and dead bands. Based on this learning algorithm, the suggested neural network can efficiently extract the input/output mapping function of the forecast process leading to high STLF accuracy. The proposed approach is tested on two practical power systems and the results obtained are compared with the results of several other recently published STLF methods. These comparisons confirm the validity of the developed approach.

  14. High-precision performance testing of the LHC power converters

    Bastos, M; Dreesen, P; Fernqvist, G; Fournier, O; Hudson, G

    2007-01-01

    The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests , short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converter and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained.

  15. Stretchers and compressors for ultra-high power laser systems

    Yakovlev, I V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2014-05-30

    This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. (review)

  16. An analysis of the performance benefits of short-term energy storage in wind-diesel hybrid power systems

    Shirazi, M.; Drouilhet, S.

    1996-01-01

    A variety of prototype high penetration wind-diesel hybrid power systems have been implemented with different amounts of energy storage. They range from systems with no energy storage to those with many hours worth of energy storage. There has been little consensus among wind-diesel system developers as to the appropriate role and amount of energy storage in such systems. Some researchers advocate providing only enough storage capacity to supply power during the time it takes the diesel genset to start. Others install large battery banks to allow the diesel(s) to operate at full load and/or to time-shift the availability of wind-generated electricity to match the demand. Prior studies indicate that for high penetration wind-diesel systems, short-term energy storage provides the largest operational and economic benefit. This study uses data collected in Deering, Alaska, a small diesel-powered village, and the hybrid systems modeling software Hybrid2 to determine the optimum amount of short-term storage for a particular high penetration wind-diesel system. These findings were then generalized by determining how wind penetration, turbulence intensity, and load variability affect the value of short term energy storage as measured in terms of fuel savings, total diesel run time, and the number of diesel starts

  17. High voltage power supplies for INDUS-2 RF system

    Badapanda, M.K.; Hannurkar, P.R.

    2003-01-01

    The RF system of Indus-2 employs klystron amplifiers operating at 505.812 MHz. A precession controlled high voltage DC supply of appropriate rating is needed for each klystron amplifier, as its bias supply. Since internal flashover and arcing are common with the operation of these klystrons and stored energies beyond particular limit inside its bias power supply is detrimental to this device, a properly designed crowbar is incorporated between each klystron and its power supply. This crowbar bypass these stored energies and helps protecting klystron under any of these unfavorable conditions. In either case, power supply sees a near short circuit across its load. So, its power circuit is designed to reduce the fault current level and its various components are also designed to withstand these fault currents, as and when it appears. Finally, operation of these high voltage power supplies (HVPS) generates lot of harmonics on the source side, which distort the input waveform substantially and reduces the input power factor also. Source multiplication between two power supplies are planned to improve upon above parameters and suitable detuned line filters are incorporated to keep the input voltage total harmonics distortion (THD) below 5 % and input power factor (IFF) near unity. (author)

  18. High average-power induction linacs

    Prono, D.S.; Barrett, D.; Bowles, E.; Caporaso, G.J.; Chen, Yu-Jiuan; Clark, J.C.; Coffield, F.; Newton, M.A.; Nexsen, W.; Ravenscroft, D.; Turner, W.C.; Watson, J.A.

    1989-01-01

    Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of ∼ 50-ns duration pulses to > 100 MeV. In this paper the authors report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

  19. High average-power induction linacs

    Prono, D.S.; Barrett, D.; Bowles, E.

    1989-01-01

    Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of /approximately/ 50-ns duration pulses to > 100 MeV. In this paper we report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

  20. Driver Circuit For High-Power MOSFET's

    Letzer, Kevin A.

    1991-01-01

    Driver circuit generates rapid-voltage-transition pulses needed to switch high-power metal oxide/semiconductor field-effect transistor (MOSFET) modules rapidly between full "on" and full "off". Rapid switching reduces time of overlap between appreciable current through and appreciable voltage across such modules, thereby increasing power efficiency.

  1. Short-Term Wind Power Interval Forecasting Based on an EEMD-RT-RVM Model

    Haixiang Zang

    2016-01-01

    Full Text Available Accurate short-term wind power forecasting is important for improving the security and economic success of power grids. Existing wind power forecasting methods are mostly types of deterministic point forecasting. Deterministic point forecasting is vulnerable to forecasting errors and cannot effectively deal with the random nature of wind power. In order to solve the above problems, we propose a short-term wind power interval forecasting model based on ensemble empirical mode decomposition (EEMD, runs test (RT, and relevance vector machine (RVM. First, in order to reduce the complexity of data, the original wind power sequence is decomposed into a plurality of intrinsic mode function (IMF components and residual (RES component by using EEMD. Next, we use the RT method to reconstruct the components and obtain three new components characterized by the fine-to-coarse order. Finally, we obtain the overall forecasting results (with preestablished confidence levels by superimposing the forecasting results of each new component. Our results show that, compared with existing methods, our proposed short-term interval forecasting method has less forecasting errors, narrower interval widths, and larger interval coverage percentages. Ultimately, our forecasting model is more suitable for engineering applications and other forecasting methods for new energy.

  2. High-order harmonic generation with short-pulse lasers

    Schafer, K.J.; Krause, J.L.; Kulander, K.C.

    1992-12-01

    Recent progress in the understanding of high-order harmonic conversion from atoms and ions exposed to high-intensity, short-pulse optical lasers is reviewed. We find that ions can produce harmonics comparable in strength to those obtained from neutral atoms, and that the emission extends to much higher order. Simple scaling laws for the strength of the harmonic emission and the maximium observable harmonic are suggested. These results imply that the photoemission observed in recent experiments in helium and neon contains contributions from ions as well as neutrals

  3. ICAN: High power neutral beam generation

    Moustaizis, S.D.; Lalousis, P.; Perrakis, K.; Auvray, P.; Larour, J.; Ducret, J.E.; Balcou, P.

    2015-01-01

    During the last few years there is an increasing interest on the development of alternative high power new negative ion source for Tokamak applications. The proposed new neutral beam device presents a number of advantages with respect to: the density current, the acceleration voltage, the relative compact dimension of the negative ion source, and the coupling of a high power laser beam for photo-neutralization of the negative ion beam. Here we numerically investigate, using a multi- fluid 1-D code, the acceleration and the extraction of high power ion beam from a Magnetically Insulated Diode (MID). The diode configuration will be coupled to a high power device capable of extracting a current up to a few kA with an accelerating voltage up to MeV. An efficiency of up to 92% of the coupling of the laser beam, is required in order to obtain a high power, up to GW, neutral beam. The new high energy, high average power, high efficiency (up to 30%) ICAN fiber laser is proposed for both the plasma generation and the photo-neutralizer configuration. (authors)

  4. High-intensity exercise and recovery during short-term ...

    to power athletes and other individuals wishing to improve performance in ... effect of creatine supplementation on physical performance. It has been reported that ... high-intensity work performance.1,2,5,16,31,36 Such activities as resistance ...

  5. Short-term power plant operation scheduling in thermal systems with long-term boundary conditions

    Wolter, H.

    1990-01-01

    For the first time, the modeling of long-term quantitative conditions within the short-term planning of the application of power stations is made via their shadow prices. It corresponds to a decomposition of the quantitative conditions by means of the method of the Langrange relaxation. The shadow prices determined by the planning for energy application regarding long- term quantitative conditions pass into the short-term planning for power station application and subsidize or rather punish the application of limited amounts as for as they are not claimed for sufficiently or excessively. The clear advantage of this modeling is that the short-term planning of power station application can deviate from the envisioned energy application regarding the total optimum, because the shadow prices contain all information about the cost effect of the energy shifts in the residual total period, which become necessary due to the deviations in the short-term period to be planned in the current short-term period. (orig./DG) [de

  6. Network model and short circuit program for the Kennedy Space Center electric power distribution system

    1976-01-01

    Assumptions made and techniques used in modeling the power network to the 480 volt level are discussed. Basic computational techniques used in the short circuit program are described along with a flow diagram of the program and operational procedures. Procedures for incorporating network changes are included in this user's manual.

  7. Short-Circuit Robustness Assessment in Power Electronic Modules for Megawatt Applications

    Iannuzzo, Francesco

    2016-01-01

    In this paper, threats and opportunities in testing of megawatt power electronic modules under short circuit are presented and discussed, together with the introduction of some basic principles of non-destructive testing, a key technique to allow post-failure analysis. The non-destructive testing...

  8. High power density carbonate fuel cell

    Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)

    1996-12-31

    Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

  9. High-Temperature Reactor For Power Generation and District Heating

    Herzberger, Karlheinz

    1987-01-01

    The multinational BBC Brown Brave Group, which has its head-quarters in Baden/Switzerland, was founded in 1891. Its German company is Brown, Brave and CIEs AGM, Mannheim. The field of operation covers wide areas of electrical engineering: These includes mainly the manufacture of installations and equipment for the generation, conversion, distribution and utilization of electric power, with special emphasis on the capital goods sector. BBC erects turnkey power plants and manufactures electrical equipment for industrial plants and urban transport and main line trains. Also of major importance are standard electrical products such as motors, switches, cables, semiconductor devices as well as measuring and control equipment. In the field of nuclear power BBC is engaged in particular in the development and construction of high-temperature reactors for the generation of electric power and process heat. The following presentation gives a short view on the milestones of the HTR development achieved in 1987

  10. High Voltage Power Transmission for Wind Energy

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  11. Gingin High Optical Power Test Facility

    Zhao, C; Blair, D G; Barrigo, P

    2006-01-01

    The Australian Consortium for Gravitational Wave Astronomy (ACIGA) in collaboration with LIGO is developing a high optical power research facility at the AIGO site, Gingin, Western Australia. Research at the facility will provide solutions to the problems that advanced gravitational wave detectors will encounter with extremely high optical power. The problems include thermal lensing and parametric instabilities. This article will present the status of the facility and the plan for the future experiments

  12. A hybrid PSO-ANFIS approach for short-term wind power prediction in Portugal

    Pousinho, H.M.I.; Mendes, V.M.F.; Catalao, J.P.S.

    2011-01-01

    The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Wind power prediction plays a key role in tackling these challenges. The contribution of this paper is to propose a new hybrid approach, combining particle swarm optimization and adaptive-network-based fuzzy inference system, for short-term wind power prediction in Portugal. Significant improvements regarding forecasting accuracy are attainable using the proposed approach, in comparison with the results obtained with five other approaches.

  13. A hybrid PSO-ANFIS approach for short-term wind power prediction in Portugal

    Pousinho, H.M.I. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Mendes, V.M.F. [Department of Electrical Engineering and Automation, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro, 1950-062 Lisbon (Portugal); Catalao, J.P.S. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Center for Innovation in Electrical and Energy Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

    2011-01-15

    The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Wind power prediction plays a key role in tackling these challenges. The contribution of this paper is to propose a new hybrid approach, combining particle swarm optimization and adaptive-network-based fuzzy inference system, for short-term wind power prediction in Portugal. Significant improvements regarding forecasting accuracy are attainable using the proposed approach, in comparison with the results obtained with five other approaches. (author)

  14. Development and advances in conventional high power RF systems

    Wilson, P.B.

    1995-06-01

    The development of rf systems capable of producing high peak power (hundreds of megawatts) at relatively short pulse lengths (0.1--5 microseconds) is currently being driven mainly by the requirements of future high energy linear colliders, although there may be applications to industrial, medical and research linacs as well. The production of high peak power rf typically involves four basic elements: a power supply to convert ac from the ''wall plug'' to dc; a modulator, or some sort of switching element, to produce pulsed dc power; an rf source to convert the pulsed dc to pulsed rf power; and possibly an rf pulse compression system to further enhance the peak rf power. Each element in this rf chain from wall plug to accelerating structure must perform with high efficiency in a linear collider application, such that the overall system efficiency is 30% or more. Basic design concepts are discussed for klystrons, modulators and rf pulse compression systems, and their present design status is summarized for applications to proposed linear colliders

  15. Inverter design for high frequency power distribution

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  16. Fine-Tuning the Energy Levels of a Nonfullerene Small-Molecule Acceptor to Achieve a High Short-Circuit Current and a Power Conversion Efficiency over 12% in Organic Solar Cells.

    Kan, Bin; Zhang, Jiangbin; Liu, Feng; Wan, Xiangjian; Li, Chenxi; Ke, Xin; Wang, Yunchuang; Feng, Huanran; Zhang, Yamin; Long, Guankui; Friend, Richard H; Bakulin, Artem A; Chen, Yongsheng

    2018-01-01

    Organic solar cell optimization requires careful balancing of current-voltage output of the materials system. Here, such optimization using ultrafast spectroscopy as a tool to optimize the material bandgap without altering ultrafast photophysics is reported. A new acceptor-donor-acceptor (A-D-A)-type small-molecule acceptor NCBDT is designed by modification of the D and A units of NFBDT. Compared to NFBDT, NCBDT exhibits upshifted highest occupied molecular orbital (HOMO) energy level mainly due to the additional octyl on the D unit and downshifted lowest unoccupied molecular orbital (LUMO) energy level due to the fluorination of A units. NCBDT has a low optical bandgap of 1.45 eV which extends the absorption range toward near-IR region, down to ≈860 nm. However, the 60 meV lowered LUMO level of NCBDT hardly changes the V oc level, and the elevation of the NCBDT HOMO does not have a substantial influence on the photophysics of the materials. Thus, for both NCBDT- and NFBDT-based systems, an unusually slow (≈400 ps) but ultimately efficient charge generation mediated by interfacial charge-pair states is observed, followed by effective charge extraction. As a result, the PBDB-T:NCBDT devices demonstrate an impressive power conversion efficiency over 12%-among the best for solution-processed organic solar cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. LCA of electricity systems with high wind power penetration

    Turconi, Roberto; O' Dwyer, C. O.; Flynn, D.

    Electricity systems are shifting from being based on fossil fuels towards renewable sources to enhance energy security and mitigate climate change. However, by introducing high shares of variable renewables - such as wind and solar - dispatchable power plants are required to vary their output...... to fulfill the remaining electrical demand, potentially increasing their environmental impacts [1,2]. In this study the environmental impacts of potential short-term future electricity systems in Ireland with high shares of wind power (35-50% of total installed capacity) were evaluated using life cycle...... considered: while not outweighing the benefits from increasing wind energy, cycling emissions are not negligible and should thus be systematically included (i.e. by using emission factors per unit of fuel input rather than per unit of power generated). Cycling emissions increased with the installed wind...

  18. Small high cooling power space cooler

    Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E. [Northrop Grumman Aerospace Systems Redondo Beach, Ca, 90278 (United States)

    2014-01-29

    The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

  19. Short steel and concrete columns under high temperatures

    A. E. P. G. A. Jacintho

    Full Text Available The growing demand for knowledge about the effect of high temperatures on structures has stimulated increasing research worldwide. This article presents experimental results for short composite steel and concrete columns subjected to high temperatures in ovens with or without an axial compression load, numerically analyzes the temperature distribution in these columns after 30 and 60 minutes and compares them with experimental results. The models consist of concrete-filled tubes of three different thicknesses and two different diameters, and the concrete fill has conventional properties that remained constant for all of the models. The stress-strain behavior of the composite columns was altered after exposure to high temperatures relative to the same columns at room temperature, which was most evident in the 60-minute tests due to the higher temperatures reached. The computational analysis adopted temperature rise curves that were obtained experimentally.

  20. Very short-term spatio-temporal wind power prediction using a censored Gaussian field

    Baxevani, Anastassia; Lenzi, Amanda

    2018-01-01

    Wind power is a renewable energy resource, that has relatively cheap installation costs and it is highly possible that will become the main energy resource in the near future. Wind power needs to be integrated efficiently into electricity grids, and to optimize the power dispatch, techniques...

  1. A highly linear power amplifier for WLAN

    Jie, Jin; Jia, Shi; Baoli, Ai; Xuguang, Zhang

    2016-02-01

    A three-stage power amplifier (PA) for WLAN application in 2.4-2.5 GHz is presented. The proposed PA employs an adaptive bias circuit to adjust the operating point of the PA to improve the linearity of the PA. Two methods to short the 2nd harmonic circuit are compared in the area of efficiency and gain of the PA. The PA is taped out in the process of 2 μm InGaP/GaAs HBT and is tested by the evaluation board. The measured results show that 31.5 dB power gain and 29.3 dBm P1dB with an associated 40.4% power added efficiency (PAE) under the single tone stimulus. Up to 26.5 dBm output power can be achieved with an error vector magnitude (EVM) of lower than 3% under the 64QAM/OFDM WLAN stimulus. Project supported by the National Natural Science Foundation of China (No. 61201244) and the Natural Science Fund of SUES (No. E1-0501-14-0168).

  2. EDM - A model for optimising the short-term power operation of a complex hydroelectric network

    Tremblay, M.; Guillaud, C.

    1996-01-01

    In order to optimize the short-term power operation of a complex hydroelectric network, a new model called EDM was added to PROSPER, a water management analysis system developed by SNC-Lavalin. PROSPER is now divided into three parts: an optimization model (DDDP), a simulation model (ESOLIN), and an economic dispatch model (EDM) for the short-term operation. The operation of the KSEB hydroelectric system (located in southern India) with PROSPER was described. The long-term analysis with monthly time steps is assisted by the DDDP, and the daily analysis with hourly or half-hourly time steps is performed with the EDM model. 3 figs

  3. A review on the young history of the wind power short-term prediction

    Costa, A.; Crespo, A.; Navarro, J.

    2008-01-01

    This paper makes a brief review on 30 years of history of the wind power short-term prediction, since the first ideas and sketches on the theme to the actual state of the art oil models and tools, giving emphasis to the most significant proposals and developments. The two principal lines of thought...... on short-term prediction (mathematical and physical) are indistinctly treated here and comparisons between models and tools are avoided, mainly because, on the one hand, a standard for a measure of performance is still not adopted and, on the other hand, it is very important that the data are exactly...

  4. High power neutral beam injection in LHD

    Tsumori, K.; Takeiri, Y.; Nagaoka, K.

    2005-01-01

    The results of high power injection with a neutral beam injection (NBI) system for the large helical device (LHD) are reported. The system consists of three beam-lines, and two hydrogen negative ion (H - ion) sources are installed in each beam-line. In order to improve the injection power, the new beam accelerator with multi-slot grounded grid (MSGG) has been developed and applied to one of the beam-lines. Using the accelerator, the maximum powers of 5.7 MW were achieved in 2003 and 2004, and the energy of 189 keV reached at maximum. The power and energy exceeded the design values of the individual beam-line for LHD. The other beam-lines also increased their injection power up to about 4 MW, and the total injection power of 13.1 MW was achieved with three beam-lines in 2003. Although the accelerator had an advantage in high power beam injection, it involved a demerit in the beam focal condition. The disadvantage was resolved by modifying the aperture shapes of the steering grid. (author)

  5. High Flux Isotope Reactor power upgrade status

    Rothrock, R.B.; Hale, R.E.; Cheverton, R.D.

    1997-01-01

    A return to 100-MW operation is being planned for the High Flux Isotope Reactor (HFIR). Recent improvements in fuel element manufacturing procedures and inspection equipment will be exploited to reduce hot spot and hot streak factors sufficiently to permit the power upgrade without an increase in primary coolant pressure. Fresh fuel elements already fabricated for future use are being evaluated individually for power upgrade potential based on their measured coolant channel dimensions

  6. Analysing the Possible Ways for Short-Term Forcing Gas Turbine Engines in Auxiliary Power Unit

    N. I. Trotskii

    2016-01-01

    Full Text Available Using a gas turbine energy unit as an example, the article discusses possible ways for forcing the short-term gas turbine engines (GTE. The introduction explains the need for forcing the air transport and marine GTE in specific driving conditions and offers the main methods. Then it analyzes the three main short-term forcing methods according to GTE power, namely: precompressor water injection, a short-term rise in temperature after the combustion chamber, and feeding an additional compressed air into combustion chamber from the reserve cylinders.The analysis of the water injection method to force a GTE presents the main provisions and calculation results of the cycle, as a function of engine power on the amount of water injected into compressor inlet. It is shown that with water injection into compressor inlet in an amount of 1% of the total airflow there is a 17% power increase in the compressor. It also lists the main implementation problems of this method and makes a comparison with the results of other studies on the water injection into compressor.Next, the article concerns the GTE short-term forcing method through the pre-turbine short-term increase in the gas temperature. The article presents the calculation results of the cycle as a function of the power and the fuel-flow rate on the gas temperature at the turbine inlet. It is shown that with increasing temperature by 80 degrees the engine power increases by 11.2% and requires 11% more fuel. In the analysis of this method arises an issue of thermal barrier coating on the blade surface. The article discusses the most common types of coatings and their main shortcomings. It lists the main challenges and some ways of their solving when using this method to implement the short-term forcing.The last method under consideration is GTE short-term forcing by feeding the compressed air into the combustion chamber from the additional reserve cylinders. It should be noted that this method is

  7. Advanced High Voltage Power Device Concepts

    Baliga, B Jayant

    2012-01-01

    Advanced High Voltage Power Device Concepts describes devices utilized in power transmission and distribution equipment, and for very high power motor control in electric trains and steel-mills. Since these devices must be capable of supporting more than 5000-volts in the blocking mode, this books covers operation of devices rated at 5,000-V, 10,000-V and 20,000-V. Advanced concepts (the MCT, the BRT, and the EST) that enable MOS-gated control of power thyristor structures are described and analyzed in detail. In addition, detailed analyses of the silicon IGBT, as well as the silicon carbide MOSFET and IGBT, are provided for comparison purposes. Throughout the book, analytical models are generated to give a better understanding of the physics of operation for all the structures. This book provides readers with: The first comprehensive treatment of high voltage (over 5000-volts) power devices suitable for the power distribution, traction, and motor-control markets;  Analytical formulations for all the device ...

  8. Optimizing the design of very high power, high performance converters

    Edwards, R.J.; Tiagha, E.A.; Ganetis, G.; Nawrocky, R.J.

    1980-01-01

    This paper describes how various technologies are used to achieve the desired performance in a high current magnet power converter system. It is hoped that the discussions of the design approaches taken will be applicable to other power supply systems where stringent requirements in stability, accuracy and reliability must be met

  9. High-voltage pulse generator for electron gun power supply

    Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.

    1987-01-01

    High-voltage pulse generator with combined capacitive and inductive energy storages for electron gun power supply is described. Hydrogen thyratron set in a short magnetic lense is a current breaker. Times of current interruption in thyratrons are in the range from 100 to 300 ns. With 1 kV charging voltage of capacitive energy storage 25 kV voltage pulse is obtained in the load. The given high-voltage pulse generator was used for supply of an electron gun generating 10-30 keV low-energy electron beam

  10. High power infrared QCLs: advances and applications

    Patel, C. Kumar N.

    2012-01-01

    QCLs are becoming the most important sources of laser radiation in the midwave infrared (MWIR) and longwave infrared (LWIR) regions because of their size, weight, power and reliability advantages over other laser sources in the same spectral regions. The availability of multiwatt RT operation QCLs from 3.5 μm to >16 μm with wall plug efficiency of 10% or higher is hastening the replacement of traditional sources such as OPOs and OPSELs in many applications. QCLs can replace CO2 lasers in many low power applications. Of the two leading groups in improvements in QCL performance, Pranalytica is the commercial organization that has been supplying the highest performance QCLs to various customers for over four year. Using a new QCL design concept, the non-resonant extraction [1], we have achieved CW/RT power of >4.7 W and WPE of >17% in the 4.4 μm - 5.0 μm region. In the LWIR region, we have recently demonstrated QCLs with CW/RT power exceeding 1 W with WPE of nearly 10 % in the 7.0 μm-10.0 μm region. In general, the high power CW/RT operation requires use of TECs to maintain QCLs at appropriate operating temperatures. However, TECs consume additional electrical power, which is not desirable for handheld, battery-operated applications, where system power conversion efficiency is more important than just the QCL chip level power conversion efficiency. In high duty cycle pulsed (quasi-CW) mode, the QCLs can be operated without TECs and have produced nearly the same average power as that available in CW mode with TECs. Multiwatt average powers are obtained even in ambient T>70°C, with true efficiency of electrical power-to-optical power conversion being above 10%. Because of the availability of QCLs with multiwatt power outputs and wavelength range covering a spectral region from ~3.5 μm to >16 μm, the QCLs have found instantaneous acceptance for insertion into multitude of defense and homeland security applications, including laser sources for infrared

  11. The NASA CSTI High Capacity Power Program

    Winter, J.M.

    1991-09-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil applications. During 1986 and 1987, the NASA Advanced Technology Program was responsible for maintaining the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In 1988, the NASA Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA advanced technology project, and provides a bridge to the NASA exploration technology programs. The elements of CSTI high capacity power development include conversion systems: Stirling and thermoelectric, thermal management, power management, system diagnostics, and environmental interactions. Technology advancement in all areas, including materials, is required to provide the growth capability, high reliability, and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems while minimizing the impact of day/night operations as well as attitudes and distance from the Sun. Significant accomplishments in all of the program elements will be discussed, along with revised goals and project timelines recently developed

  12. High-power VCSELs for smart munitions

    Geske, Jon; MacDougal, Michael; Cole, Garrett; Snyder, Donald

    2006-08-01

    The next generation of low-cost smart munitions will be capable of autonomously detecting and identifying targets aided partly by the ability to image targets with compact and robust scanning rangefinder and LADAR capabilities. These imaging systems will utilize arrays of high performance, low-cost semiconductor diode lasers capable of achieving high peak powers in pulses ranging from 5 to 25 nanoseconds in duration. Aerius Photonics is developing high-power Vertical-Cavity Surface-Emitting Lasers (VCSELs) to meet the needs of these smart munitions applications. The authors will report the results of Aerius' development program in which peak pulsed powers exceeding 60 Watts were demonstrated from single VCSEL emitters. These compact packaged emitters achieved pulse energies in excess of 1.5 micro-joules with multi kilo-hertz pulse repetition frequencies. The progress of the ongoing effort toward extending this performance to arrays of VCSEL emitters and toward further improving laser slope efficiency will be reported.

  13. High power all solid state VUV lasers

    Zhang, Shen-jin; Cui, Da-fu; Zhang, Feng-feng; Xu, Zhi; Wang, Zhi-min; Yang, Feng; Zong, Nan; Tu, Wei; Chen, Ying; Xu, Hong-yan; Xu, Feng-liang; Peng, Qin-jun; Wang, Xiao-yang; Chen, Chuang-tian; Xu, Zu-yan

    2014-01-01

    Highlights: • Polarization and pulse repetition rate adjustable ps 177.3 nm laser was developed. • Wavelength tunable ns, ps and fs VUV lasers were developed. • High power ns 177.3 nm laser with narrow linewidth was investigated. - Abstract: We report the investigation on the high power all solid state vacuum ultra-violet (VUV) lasers by means of nonlinear frequency conversion with KBe 2 BO 3 F 2 (KBBF) nonlinear crystal. Several all solid state VUV lasers have developed in our group, including polarization and pulse repetition rate adjustable picosecond 177.3 nm VUV laser, wavelength tunable nanosecond, picosecond and femtosecond VUV lasers, high power ns 177.3 nm laser with narrow linewidth. The VUV lasers have impact, accurate and precise advantage

  14. High Power High Efficiency Diode Laser Stack for Processing

    Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

    2018-03-01

    High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

  15. High to ultra-high power electrical energy storage.

    Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

    2011-12-14

    High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

  16. Prospects of the high power iodine laser

    Hohla, K.; Brederlow, G.; Fill, E.; Volk, R.; Witte, K.J.

    1976-09-01

    The characteristic properties of the iodine laser (gaseous laser substance, photolytic pump mechanism, variable stimulated emission cross-section) made it possible in a relatively short time to generate ns pulses in the kJ range. The Asterix II and III iodine laser systems at IPP are working successfully, and the question arises what prospects are afforded for further iodine laser development. What are the problems that have to be clarified in order to build 10 or 100 kJ systems for laser fusion experiments. According to our experience these can be classified as follows: 1) Short pulse generation and contrast ratio, 2) pulse shaping in a high-gain laser and amplification in the coherent time range, 3) non-linear properties at high intensities, 4) scalable pumping schemes and chemical processes. (orig./WL) [de

  17. Signature of short distance physics on inflation power spectrum and CMB anisotropy

    Das, Suratna; Mohanty, Subhendra

    2009-01-01

    The inflaton field responsible for inflation may not be a canonical fundamental scalar. It is possible that the inflaton is a composite of fermions or it may have a decay width. In these cases the standard procedure for calculating the power spectrum is not applicable and a new formalism needs to be developed to determine the effect of short range interactions of the inflaton on the power spectrum and the CMB anisotropy. We develop a general formalism for computing the power spectrum of curvature perturbations for such non-canonical cases by using the flat space Källén-Lehmann spectral function in curved quasi-de Sitter space assuming implicitly that the Bunch-Davis boundary conditions enforces the inflaton mode functions to be plane wave in the short wavelength limit and a complete set of mode functions exists in quasi-de Sitter space. It is observed that the inflaton with a decay width suppresses the power at large scale while a composite inflaton's power spectrum oscillates at large scales. These observations may be vindicated in the WMAP data and confirmed by future observations with PLANCK

  18. Short-term wind power forecasting in Portugal by neural networks and wavelet transform

    Catalao, J.P.S. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Center for Innovation in Electrical and Energy Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Pousinho, H.M.I. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Mendes, V.M.F. [Department of Electrical Engineering and Automation, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro, 1950-062 Lisbon (Portugal)

    2011-04-15

    This paper proposes artificial neural networks in combination with wavelet transform for short-term wind power forecasting in Portugal. The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Hence, good forecasting tools play a key role in tackling these challenges. Results from a real-world case study are presented. A comparison is carried out, taking into account the results obtained with other approaches. Finally, conclusions are duly drawn. (author)

  19. Simple and reliable procedure for the evaluation of short-term dynamic processes in power systems

    Popovic, D P

    1986-10-01

    An efficient approach is presented to the solution of the short-term dynamics model in power systems. It consists of an adequate algebraic treatment of the original system of nonlinear differential equations, using linearization, decomposition and Cauchy's formula. The simple difference equations obtained in this way are incorporated into a model of the electrical network, which is of a low order compared to the ones usually used. Newton's method is applied to the model formed in this way, which leads to a simple and reliable iterative procedure. The characteristics of the procedure developed are demonstrated on examples of transient stability analysis of real power systems. 12 refs.

  20. A Short-Current Control Method for Constant Frequency Current-Fed Wireless Power Transfer Systems

    Yanling Li

    2017-04-01

    Full Text Available Frequency drift is a serious problem in Current-Fed Wireless Power Transfer (WPT systems. When the operating frequency is drifting from the inherent Zero Voltage Switching (ZVS frequency of resonant network, large short currents will appear and damage the switches. In this paper, an inductance-dampening method is proposed to inhibit short currents and achieve constant-frequency operation. By adding a small auxiliary series inductance in the primary resonant network, short currents are greatly attenuated to a safe level. The operation principle and steady-state analysis of the system are provided. An overlapping time self-regulating circuit is designed to guarantee ZVS running. The range of auxiliary inductances is discussed and its critical value is calculated exactly. The design methodology is described and a design example is presented. Finally, a prototype is built and the experimental results verify the proposed method.

  1. Evaluating the quality of scenarios of short-term wind power generation

    Pinson, Pierre; Girard, R.

    2012-01-01

    Scenarios of short-term wind power generation are becoming increasingly popular as input to multi-stage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benets from...... their use in decision-making. So far however, their verication is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verication tools, as well...... as diagnostic approaches based on event-based verication are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools....

  2. Powersail High Power Propulsion System Design Study

    Gulczinski, Frank S., III

    2000-11-01

    A desire by the United States Air Force to exploit the space environment has led to a need for increased on-orbit electrical power availability. To enable this, the Air Force Research Laboratory Space Vehicles Directorate (AFRL/ VS) is developing Powersail: a two-phased program to demonstrate high power (100 kW to 1 MW) capability in space using a deployable, flexible solar array connected to the host spacecraft using a slack umbilical. The first phase will be a proof-of-concept demonstration at 50 kW, followed by the second phase, an operational system at full power. In support of this program, the AFRL propulsion Directorate's Spacecraft Propulsion Branch (AFRL/PRS ) at Edwards AFB has commissioned a design study of the Powersail High Power Propulsion System. The purpose of this study, the results of which are summarized in this paper, is to perform mission and design trades to identify potential full-power applications (both near-Earth and interplanetary) and the corresponding propulsion system requirements and design. The design study shall farther identify a suitable low power demonstration flight that maximizes risk reduction for the fully operational system. This propulsion system is expected to be threefold: (1) primary propulsion for moving the entire vehicle, (2) a propulsion unit that maintains the solar array position relative to the host spacecraft, and (3) control propulsion for maintaining proper orientation for the flexible solar array.

  3. Reactor G1: high power experiments

    Laage, F. de; Teste du Baillet, A.; Veyssiere, A.; Wanner, G.

    1957-01-01

    The experiments carried out in the starting-up programme of the reactor G1 comprised a series of tests at high power, which allowed the following points to be studied: 1- Effect of poisoning by Xenon (absolute value, evolution). 2- Temperature coefficients of the uranium and graphite for a temperature distribution corresponding to heating by fission. 3- Effect of the pressure (due to the coiling system) on the reactivity. 4- Calibration of the security rods as a function of their position in the pile (1). 5- Temperature distribution of the graphite, the sheathing, the uranium and the air leaving the canals, in a pile running normally at high power. 6- Neutron flux distribution in a pile running normally at high power. 7- Determination of the power by nuclear and thermodynamic methods. These experiments have been carried out under two very different pile conditions. From the 1. to the 15. of August 1956, a series of power increases, followed by periods of stabilisation, were induced in a pile containing uranium only, in 457 canals, amounting to about 34 tons of fuel. A knowledge of the efficiency of the control rods in such a pile has made it possible to measure with good accuracy the principal effects at high temperatures, that is, to deal with points 1, 2, 3, 5. Flux charts giving information on the variations of the material Laplacian and extrapolation lengths in the reflector have been drawn up. Finally the thermodynamic power has been measured under good conditions, in spite of some installation difficulties. On September 16, the pile had its final charge of 100 tons. All the canals were loaded, 1,234 with uranium and 53 (i.e. exactly 4 per cent of the total number) with thorium uniformly distributed in a square lattice of 100 cm side. Since technical difficulties prevented the calibration of the control rods, the measurements were limited to the determination of the thermodynamic power and the temperature distributions (points 5 and 7). This report will

  4. High power RF transmission line component development

    Hong, B. G.; Hwang, C. K.; Bae, Y. D.; Yoon, J. S.; Wang, S. J.; Gu, S. H.; Yang, J. R.; Hahm, Y. S.; Oh, G. S.; Lee, J. R.; Lee, W. I.; Park, S. H.; Kang, M. S.; Oh, S. H.; Lee, W.I.

    1999-12-01

    We developed the liquid stub and phase shifter which are the key high RF power transmission line components. They show reliable operation characteristics and increased insulation capability, and reduced the size by using liquid (silicon oil, dielectric constant ε=2.72) instead of gas for insulating dielectric material. They do not have finger stock for the electric contact so the local temperature rise due to irregular contact and RF breakdown due to scratch in conductor are prevented. They can be utilized in broadcasting, radar facility which require high RF power transmission. Moreover, they are key components in RF heating system for fusion reactor. (author)

  5. High power RF transmission line component development

    Hong, B. G.; Hwang, C. K.; Bae, Y. D.; Yoon, J. S.; Wang, S. J.; Gu, S. H.; Yang, J. R.; Hahm, Y. S.; Oh, G. S.; Lee, J. R.; Lee, W. I.; Park, S. H.; Kang, M. S.; Oh, S. H.; Lee, W.I

    1999-12-01

    We developed the liquid stub and phase shifter which are the key high RF power transmission line components. They show reliable operation characteristics and increased insulation capability, and reduced the size by using liquid (silicon oil, dielectric constant {epsilon}=2.72) instead of gas for insulating dielectric material. They do not have finger stock for the electric contact so the local temperature rise due to irregular contact and RF breakdown due to scratch in conductor are prevented. They can be utilized in broadcasting, radar facility which require high RF power transmission. Moreover, they are key components in RF heating system for fusion reactor. (author)

  6. High voltage superconducting switch for power application

    Mawardi, O.; Ferendeci, A.; Gattozzi, A.

    1983-01-01

    This paper reports the development of a novel interrupter which meets the requirements of a high voltage direct current (HVDC) power switch and at the same time doubles as a current limiter. The basic concept of the interrupter makes use of a fast superconducting, high capacity (SHIC) switch that carries the full load current while in the superconducting state and reverts to the normal resistive state when triggered. Typical design parameters are examined for the case of a HVDC transmission line handling 2.5KA at 150KVDC. The result is a power switch with superior performance and smaller size than the ones reported to date

  7. Advances in Very High Frequency Power Conversion

    Kovacevic, Milovan

    Resonant and quasi-resonant converters operated at frequencies above 30 MHz have attracted special attention in the last two decades. Compared to conventional converters operated at ~100 kHz, they offer significant advantages: smaller volume and weight, lower cost, and faster transient performance....... Excellent performance and small size of magnetic components and capacitors at very high frequencies, along with constant advances in performance of power semiconductor devices, suggests a sizable shift in consumer power supplies market into this area in the near future. To operate dc-dc converter power...... method provides low complexity and low gate loss simultaneously. A direct design synthesis method is provided for resonant SEPIC converters employing this technique. Most experimental prototypes were developed using low cost, commercially available power semiconductors. Due to very fast transient...

  8. Advanced Output Coupling for High Power Gyrotrons

    Read, Michael [Calabazas Creek Research, Inc., San Mateo, CA (United States); Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Guss, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lohr, John [General Atomics, La Jolla, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States); Bui, Thuc [Calabazas Creek Research, Inc., San Mateo, CA (United States)

    2016-11-28

    The Phase II program developed an internal RF coupler that transforms the whispering gallery RF mode produced in gyrotron cavities to an HE11 waveguide mode propagating in corrugated waveguide. This power is extracted from the vacuum using a broadband, chemical vapor deposited (CVD) diamond, Brewster angle window capable of transmitting more than 1.5 MW CW of RF power over a broad range of frequencies. This coupling system eliminates the Mirror Optical Units now required to externally couple Gaussian output power into corrugated waveguide, significantly reducing system cost and increasing efficiency. The program simulated the performance using a broad range of advanced computer codes to optimize the design. Both a direct coupler and Brewster angle window were built and tested at low and high power. Test results confirmed the performance of both devices and demonstrated they are capable of achieving the required performance for scientific, defense, industrial, and medical applications.

  9. Short Pulse Switches for Airborne High Power Supplies

    1973-10-01

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  10. Short term and medium term power distribution load forecasting by neural networks

    Yalcinoz, T.; Eminoglu, U.

    2005-01-01

    Load forecasting is an important subject for power distribution systems and has been studied from different points of view. In general, load forecasts should be performed over a broad spectrum of time intervals, which could be classified into short term, medium term and long term forecasts. Several research groups have proposed various techniques for either short term load forecasting or medium term load forecasting or long term load forecasting. This paper presents a neural network (NN) model for short term peak load forecasting, short term total load forecasting and medium term monthly load forecasting in power distribution systems. The NN is used to learn the relationships among past, current and future temperatures and loads. The neural network was trained to recognize the peak load of the day, total load of the day and monthly electricity consumption. The suitability of the proposed approach is illustrated through an application to real load shapes from the Turkish Electricity Distribution Corporation (TEDAS) in Nigde. The data represents the daily and monthly electricity consumption in Nigde, Turkey

  11. The Effects of Music on High-intensity Short-term Exercise in Well Trained Athletes.

    Jarraya, Mohamed; Chtourou, Hamdi; Aloui, Asma; Hammouda, Omar; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2012-12-01

    The purpose of this investigation was to assess the effects of listening to music during warm-up on short-term supramaximal performances during the 30-s Wingate test in highly trained athletes. Twelve young male athletes (20.6±1.8 yrs, 177±4.4 cm and 72.3±5.3 kg) underwent two Wingate tests in separate sessions with a recovery period of 48 h in-between, either after a 10 min of warm-up with (MWU) or without (NMWU) music. High tempo music (>120 to 140bpm) was selected for the study. Heart rate (HR) and rate of perceived exertion (RPE) were recorded after the warm-up (for HR = average of warm-up) and immediately after the Wingate test. HR, RPE and the fatigue index during the Wingate test are not affected by the incorporation of music during warm-up. However, power output (P(peak) and P(mean)) was significantly higher after MWU than NMWU (Peffect of music during warm-up on short-term supramaximal performances. As it's a legal method and an additional aid, music may be used during warm-up before performing activities requiring powerful lower limbs' muscles contractions during short-term supramaximal exercises.

  12. Why do short term workers have high mortality?

    Kolstad, Henrik; Olsen, Jørn

    1999-01-01

    or violence, the rate ratios for short term employment were 2.30 (95% Cl 1.74-3.06) and 1.86 (95% Cl 1.35-2.56), respectively. An unhealthy lifestyle may also be a determinant of short term employment. While it is possible in principle to adjust for lifestyle factors if proper data are collected, the health......Increased mortality is often reported among workers in short term employment. This may indicate either a health-related selection process or the presence of different lifestyle or social conditions among short term workers. The authors studied these two aspects of short term employment among 16...

  13. Characterization of the voltage control systems and speed of a synchronous machine of high power for short circuit testing; Caracterizacion de los sistemas de control de voltaje y velocidad de una maquina sincrona de alta potencia para pruebas de corto circuito

    Segura Ozuna, Victor Octavio; Hernandez Rodriguez, Isaura Victoria; Alcaide Godinez, Indira Xochiquetzal; Garduno Ramirez, Raul; Montero Cervantes, Julio Cesar [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Ruiz Rodriguez, Genaro; Martinez Torres; Ricardo [CFE-LAPEM, Irapuato, Guanajuato (Mexico)

    2012-07-01

    This paper introduces a characterization of the behavior of the speed and voltage control systems of a special purpose synchronous machine (GCC) based on measuring and monitoring physical signals, and recording of the sampled waveforms. Basically, the GCC supplies the energy to perform high-power short-circuits tests to certify electrical equipment and components, as required by the Comision Federal de Electricidad (CFE) in Mexico. The GCC operates alternately as motor and generator. With the GCC operating as motor, speed control during startup, acceleration, re-acceleration and braking is carried out by a static frequency converter (SFC). Complementary, the voltage controller manipulates excitation power to control terminal voltage when the GCC operates as generator and regulates excitation current when the GCC operates as motor. Compared to conventional voltage regulation systems, which must go off in case of short-circuit, the GCC voltage regulator must keep controlling field excitation to maintain the required line current and terminal voltage during short-circuit tests. Monitoring of physical signals was carried out with a portable data acquisition system based on SCXI and PXI digital platforms. A total of 78 signals were monitored with a 6 kHz sampling rate that was enough to obtain detailed signal waveforms. Data captured was processed and plotted for analysis. The signal graphs show the current real behavior of both, the voltage control system and the speed control system, and constitute a precise characterization of their behavior. [Spanish] Este documento presenta una caracterizacion del comportamiento de los sistemas de control de velocidad y voltaje de una maquina sincrona de proposito especial (GCC) basada en la medicion y monitoreo de senales fisicas, asi como en el registro de las formas de onda muestreadas. Basicamente, la GCC suministra la energia para efectuar pruebas de corto circuito de alta potencia para certificar equipo y componentes

  14. High power switches for ion induction linacs

    Humphries, S.; Savage, M.; Saylor, W.B.

    1985-01-01

    The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystronlike interaction with the accelerating cavities, leading to enhanced momentum spread. In this paper, we describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4

  15. High power switches for ion induction linacs

    Humphries, S. Jr.; Savage, M.; Saylor, W.B.

    1985-01-01

    The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystron-like interaction with the accelerating cavities leading to enhanced momentum spread. In this paper, the author describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4

  16. High power RF oscillator with Marx generators

    Murase, Hiroshi; Hayashi, Izumi

    1980-01-01

    A method to maintain RF oscillation by using many Marx generators was proposed and studied experimentally. Many charging circuits were connected to an oscillator circuit, and successive pulsed charging was made. This successive charging amplified and maintained the RF oscillation. The use of vacuum gaps and high power silicon diodes improved the characteristics of RF current cut-off of the circuit. The efficiency of the pulsed charging from Marx generators to a condenser was theoretically investigated. The theoretical result showed the maximum efficiency of 0.98. The practical efficiency obtained by using a proposed circuit with a high power oscillator was in the range 0.50 to 0.56. The obtained effective output power of the RF pulses was 11 MW. The maximum holding time of the RF pulses was about 21 microsecond. (Kato, T.)

  17. Development of a high power femtosecond laser

    Neethling, PH

    2010-10-01

    Full Text Available The Laser Research Institute and the CSIR National Laser Centre are developing a high power femtosecond laser system in a joint project with a phased approach. The laser system consists of an fs oscillator and a regenerative amplifier. An OPCPA...

  18. Targets for high power neutral beams

    Kim, J.

    1980-01-01

    Stopping high-power, long-pulse beams is fast becoming an engineering challenge, particularly in neutral beam injectors for heating magnetically confined plasmas. A brief review of neutral beam target technology is presented along with heat transfer calculations for some selected target designs

  19. Exploring novel high power density concepts for attractive fusion systems

    Abdou, M.A. [California State Univ., Los Angeles, CA (United States). Dept. of Mechanical Engineering; APEX Team

    1999-05-01

    The advanced power extraction study is aimed at exploring innovative concepts for fusion power technology (FPT) that can tremendously enhance the potential of fusion as an attractive and competitive energy source. Specifically, the study is exploring new and `revolutionary` concepts that can provide the capability to efficiently extract heat from systems with high neutron and surface heat loads while satisfying all the FPT functional requirements and maximizing reliability, maintainability, safety, and environmental requirements. The primary criteria for measuring performance of the new concepts are: (1) high power density capability with a peak neutron wall load (NWL) of {proportional_to}10 MW m{sup -2} and surface heat flux of {proportional_to}2 MW m{sup -2}; (2) high power conversion efficiency, {proportional_to}40% net; and (3) clear potential to achieve high availability; specifically low failure rate, large design margin, and short downtime for maintenance. A requirement that MTBF{>=}43 MTTR was derived as a necessary condition to achieve the required first wall/blanket availability, where MTBF is the mean time between failures and MTTR is the mean time to recover. Highlights of innovative and promising new concepts that may satisfy these criteria are provided. (orig.) 40 refs.

  20. Ultrafast terawatt laser sources for high-field particle acceleration and short wavelength generation

    Downer, M.C.

    1996-01-01

    The Laser Sources working group concerned itself with recent advances in and future requirements for the development of laser sources relevant to high-energy physics (HEP) colliders, small scale accelerators, and the generation of short wave-length radiation. We heavily emphasized pulsed terawatt peak power laser sources for several reasons. First, their development over the past five years has been rapid and multi-faceted, and has made relativistic light intensity available to the advanced accelerator community, as well as the wider physics community, for the first time. Secondly, they have strongly impacted plasma-based accelerator research over the past two years, producing the first experimental demonstrations of the laser wakefield accelerator (LWFA) in both its resonantly-driven and self-modulated forms. Thirdly, their average power and wall-plug efficiency currently fall well short of projected requirements for future accelerators and other high average power applications, but show considerable promise for improving substantially over the next few years. A review of this rapidly emerging laser technology in the context of advanced accelerator research is therefore timely

  1. Reduced filamentation in high power semiconductor lasers

    Skovgaard, Peter M. W.; McInerney, John; O'Brien, Peter

    1999-01-01

    High brightness semiconductor lasers have applications in fields ranging from material processing to medicine. The main difficulty associated with high brightness is that high optical power densities cause damage to the laser facet and thus require large apertures. This, in turn, results in spatio......-temporal instabilities such as filamentation which degrades spatial coherence and brightness. We first evaluate performance of existing designs with a “top-hat” shaped transverse current density profile. The unstable nature of highly excited semiconductor material results in a run-away process where small modulations...

  2. Comparison of two new short-term wind-power forecasting systems

    Ramirez-Rosado, Ignacio J. [Department of Electrical Engineering, University of Zaragoza, Zaragoza (Spain); Fernandez-Jimenez, L. Alfredo [Department of Electrical Engineering, University of La Rioja, Logrono (Spain); Monteiro, Claudio; Sousa, Joao; Bessa, Ricardo [FEUP, Fac. Engenharia Univ. Porto (Portugal)]|[INESC - Instituto de Engenharia de Sistemas e Computadores do Porto, Porto (Portugal)

    2009-07-15

    This paper presents a comparison of two new advanced statistical short-term wind-power forecasting systems developed by two independent research teams. The input variables used in both systems were the same: forecasted meteorological variable values obtained from a numerical weather prediction model; and electric power-generation registers from the SCADA system of the wind farm. Both systems are described in detail and the forecasting results compared, revealing great similarities, although the proposed structures of the two systems are different. The forecast horizon for both systems is 72 h, allowing the use of the forecasted values in electric market operations, as diary and intra-diary power generation bid offers, and in wind-farm maintenance planning. (author)

  3. High Efficiency Reversible Fuel Cell Power Converter

    Pittini, Riccardo

    as well as different dc-ac and dc-dc converter topologies are presented and analyzed. A new ac-dc topology for high efficiency data center applications is proposed and an efficiency characterization based on the fuel cell stack I-V characteristic curve is presented. The second part discusses the main...... converter components. Wide bandgap power semiconductors are introduced due to their superior performance in comparison to traditional silicon power devices. The analysis presents a study based on switching loss measurements performed on Si IGBTs, SiC JFETs, SiC MOSFETs and their respective gate drivers...

  4. ELBE Center for High-Power Radiation Sources

    Peter Dr. Michel

    2016-01-01

    Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

  5. Very high power THz radiation at Jefferson Lab

    Carr, G.L.; Martin, Michael C.; McKinney, Wayne R.; Jordan, K.; Neil, George R.; Williams, G.P.

    2002-01-01

    We report the production of high power (20 watts average, ∼;1 Megawatt peak) broadband THz light based on coherent emission from relativistic electrons. We describe the source, presenting theoretical calculations and their experimental verification. For clarity we compare this source with one based on ultrafast laser techniques, and in fact the radiation has qualities closely analogous to that produced by such sources, namely that it is spatially coherent, and comprises short duration pulses with transform-limited spectral content. In contrast to conventional THz radiation, however, the intensity is many orders of magnitude greater due to the relativistic enhancement

  6. Short-term optimal wind power generation capacity in liberalized electricity markets

    Olsina, Fernando; Roescher, Mark; Larisson, Carlos; Garces, Francisco

    2007-01-01

    Mainly because of environmental concerns and fuel price uncertainties, considerable amounts of wind-based generation capacity are being added to some deregulated power systems. The rapid wind development registered in some countries has essentially been driven by strong subsidizing programs. Since wind investments are commonly isolated from market signals, installed wind capacity can be higher than optimal, leading to distortions of the power prices with a consequent loss of social welfare. In this work, the influence of wind generation on power prices in the framework of a liberalized electricity market has been assessed by means of stochastic simulation techniques. The developed methodology allows investigating the maximal wind capacity that would be profitably deployed if wind investments were subject to market conditions only. For this purpose, stochastic variables determining power prices are accurately modeled. A test system resembling the size and characteristics of the German power system has been selected for this study. The expected value of the optimal, short-term wind capacity is evaluated for a considerable number of random realizations of power prices. The impact of dispersing the wind capacity over statistical independent wind sites has also been evaluated. The simulation results reveal that fuel prices, installation and financing costs of wind investments are very influential parameters on the maximal wind capacity that might be accommodated in a market-based manner

  7. Short-term load and wind power forecasting using neural network-based prediction intervals.

    Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas

    2014-02-01

    Electrical power systems are evolving from today's centralized bulk systems to more decentralized systems. Penetrations of renewable energies, such as wind and solar power, significantly increase the level of uncertainty in power systems. Accurate load forecasting becomes more complex, yet more important for management of power systems. Traditional methods for generating point forecasts of load demands cannot properly handle uncertainties in system operations. To quantify potential uncertainties associated with forecasts, this paper implements a neural network (NN)-based method for the construction of prediction intervals (PIs). A newly introduced method, called lower upper bound estimation (LUBE), is applied and extended to develop PIs using NN models. A new problem formulation is proposed, which translates the primary multiobjective problem into a constrained single-objective problem. Compared with the cost function, this new formulation is closer to the primary problem and has fewer parameters. Particle swarm optimization (PSO) integrated with the mutation operator is used to solve the problem. Electrical demands from Singapore and New South Wales (Australia), as well as wind power generation from Capital Wind Farm, are used to validate the PSO-based LUBE method. Comparative results show that the proposed method can construct higher quality PIs for load and wind power generation forecasts in a short time.

  8. Design and development of high voltage high power operational ...

    address this challenge, a) Designing a discrete power opamp with high .... the use of high-impedance feedback networks, thus minimizing their output loading ... Spice simulation is done for the circuit and results are given in figures 4a–c.

  9. Voltage generators of high voltage high power accelerators

    Svinin, M.P.

    1981-01-01

    High voltage electron accelerators are widely used in modern radiation installations for industrial purposes. In the near future further increasing of their power may be effected, which enables to raise the efficiency of the radiation processes known and to master new power-consuming production in industry. Improvement of HV generators by increasing their power and efficiency is one of many scientific and engineering aspects the successful solution of which provides further development of these accelerators and their technical parameters. The subject is discussed in detail. (author)

  10. High impact data visualization with Power View, Power Map, and Power BI

    Aspin, Adam

    2014-01-01

    High Impact Data Visualization with Power View, Power Map, and Power BI helps you take business intelligence delivery to a new level that is interactive, engaging, even fun, all while driving commercial success through sound decision-making. Learn to harness the power of Microsoft's flagship, self-service business intelligence suite to deliver compelling and interactive insight with remarkable ease. Learn the essential techniques needed to enhance the look and feel of reports and dashboards so that you can seize your audience's attention and provide them with clear and accurate information. Al

  11. A High Power Linear Solid State Pulser

    Boris Yen; Brent Davis; Rex Booth

    1999-01-01

    Particle Accelerators require high voltage and often high power. Typically the high voltage/power generation utilizes a topology with an extra energy store and a switching means to extract that stored energy. The switches may be active or passive devices. Active switches are hard or soft vacuum tubes, or semiconductors. When required voltages exceed tens of kilovolts, numerous semiconductors are stacked to withstand that potential. Such topologies can use large numbers of critical parts that, when in series, compromise the system reliability and performance. This paper describes a modular, linear, solid state amplifier which uses a parallel array of semiconductors, coupled with transmission line transformers. Such a design can provide output signals with voltages exceeding 10kV (into 50-ohms), and with rise and fall times (10-90 % amplitude) that are less than 1--ns. This compact solid state amplifier is modular, and has both hot-swap and soft fail capabilities

  12. High prices on electric power now again?

    Doorman, Gerard

    2003-01-01

    Deregulation of the electric power market has yielded low prices for the consumers throughout the 1990s. Consumption has now increased considerably, but little new production has been added. This results in high prices in dry years, but to understand this one must understand price formation in the Nordic spot market. The high prices are a powerful signal to the consumers to reduce consumption, but they are also a signal to the producers to seize any opportunity to increase production. However, the construction of new dams etc. stirs up the environmentalists. Ordinary consumers may protect themselves against high prices by signing fixed-price contracts. For those who can tolerate price fluctuations, spot prices are a better alternative than the standard contract with variable price

  13. The Effect of Current-Limiting Reactors on the Tripping of Short Circuits in High-Voltage Electrical Equipment

    Volkov, M. S.; Gusev, Yu. P.; Monakov, Yu. V.; Cho, Gvan Chun

    2016-01-01

    The insertion of current-limiting reactors into electrical equipment operating at a voltage of 110 and 220 kV produces a change in the parameters of the transient recovery voltages at the contacts of the circuit breakers for disconnecting short circuits, which could be the reason for the increase in the duration of the short circuit, damage to the electrical equipment and losses in the power system. The results of mathematical modeling of the transients, caused by tripping of the short circuit in a reactive electric power transmission line are presented, and data are given on the negative effect of a current-limiting resistor on the rate of increase and peak value of the transient recovery voltages. Methods of ensuring the standard requirements imposed on the parameters of the transient recovery voltages when using current-limiting reactors in the high-voltage electrical equipment of power plants and substations are proposed and analyzed

  14. High average power linear induction accelerator development

    Bayless, J.R.; Adler, R.J.

    1987-07-01

    There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs

  15. High intensive short laser pulse interaction with submicron clusters media

    Faenov, A. Ya

    2008-01-01

    The interaction of short intense laser pulses with structured targets, such as clusters, exhibits unique features, stemming from the enhanced absorption of the incident laser light compared to solid targets. Due to the increased absorption, these targets are heated significantly, leading to enhanced emission of x rays in the keV range and generation of electrons and multiple charged ions with kinetic energies from tens of keV to tens of MeV. Possible applications of these targets can be an electron/ion source for a table top accelerator, a neutron source for a material damage study, or an x ray source for microscopy or lithography. The overview of recent results, obtained by the high intensive short laser pulse interaction with different submicron clusters media will be presented. High resolution K and L shell spectra of plasma generated by superintense laser irradiation of micron sized Ar, Kr and Xe clusters have been measured with intensity 10"17"-10"19"W/cm"2"and a pulse duration of 30-1000fs. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X ray line yield and the ion kinetic energy. Irradiation of clusters, produced from such gas mixture, by a fs Ti:Sa laser pulses allows to enhance the soft X ray radiation of Heβ(665.7eV)and Lyα(653.7eV)of Oxygen in 2-8 times compare with the case of using as targets pure CO"2"or N"2"O clusters and reach values 2.8x10"10"(∼3μJ)and 2.7x10"10"(∼2.9μJ)ph/(sr·pulse), respectively. Nanostructure conventional soft X ray images of 100nm thick Mo and Zr foils in a wide field of view (cm"2"scale)with high spatial resolution (700nm)are obtained using the LiF crystals as soft X ray imaging detectors. When the target used for the ion acceleration studies consists of solid density clusters embedded into the background gas, its irradiation by high intensity laser light makes the target

  16. High power gyrotrons: a close perspective

    Kartikeyan, M.V.

    2012-01-01

    Gyrotrons and their variants, popularly known as gyrodevices are millimetric wave sources provide very high powers ranging from long pulse to continuous wave (CW) for various technological, scientific and industrial applications. From their conception (monotron-version) in the late fifties until their successful development for various applications, these devices have come a long way technologically and made an irreversible impact on both users and developers. The possible applications of high power millimeter and sub-millimeter waves from gyrotrons and their variants (gyro-devices) span a wide range of technologies. The plasma physics community has already taken advantage of the recent advances of gyrotrons in the areas of RF plasma production, heating, non-inductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as lower hybrid current drive (LHCD) (8 GHz), electron cyclotron resonance heating (ECRH) (28-170-220 GHz), electron cyclotron current drive (ECCD), collective Thomson scattering (CTS), heat-wave propagation experiments, and space-power grid (SPG) applications. Other important applications of gyrotrons are electron cyclotron resonance (ECR) discharges for the generation of multi- charged ions and soft X-rays, as well as industrial materials processing and plasma chemistry. Submillimeter wave gyrotrons are employed in high frequency, broadband electron paramagnetic resonance (EPR) spectroscopy. Additional future applications await the development of novel high power gyro-amplifiers and devices for high resolution radar ranging and imaging in atmospheric and planetary science as well as deep space and specialized satellite communications, RF drivers for next generation high gradient linear accelerators (supercolliders), high resolution Doppler radar, radar ranging and imaging in atmospheric and planetary science, drivers for next-generation high-gradient linear accelerators

  17. Visible high power fiber coupled diode lasers

    Köhler, Bernd; Drovs, Simon; Stoiber, Michael; Dürsch, Sascha; Kissel, Heiko; Könning, Tobias; Biesenbach, Jens; König, Harald; Lell, Alfred; Stojetz, Bernhard; Löffler, Andreas; Strauß, Uwe

    2018-02-01

    In this paper we report on further development of fiber coupled high-power diode lasers in the visible spectral range. New visible laser modules presented in this paper include the use of multi single emitter arrays @ 450 nm leading to a 120 W fiber coupled unit with a beam quality of 44 mm x mrad, as well as very compact modules with multi-W output power from 405 nm to 640 nm. However, as these lasers are based on single emitters, power scaling quickly leads to bulky laser units with a lot of optical components to be aligned. We also report on a new approach based on 450 nm diode laser bars, which dramatically reduces size and alignment effort. These activities were performed within the German government-funded project "BlauLas": a maximum output power of 80 W per bar has been demonstrated @ 450 nm. We show results of a 200 μm NA0.22 fiber coupled 35 W source @ 450 nm, which has been reduced in size by a factor of 25 compared to standard single emitter approach. In addition, we will present a 200 μm NA0.22 fiber coupled laser unit with an output power of 135 W.

  18. High power VCSELs for miniature optical sensors

    Geske, Jon; Wang, Chad; MacDougal, Michael; Stahl, Ron; Follman, David; Garrett, Henry; Meyrath, Todd; Snyder, Don; Golden, Eric; Wagener, Jeff; Foley, Jason

    2010-02-01

    Recent advances in Vertical-cavity Surface-emitting Laser (VCSEL) efficiency and packaging have opened up alternative applications for VCSELs that leverage their inherent advantages over light emitting diodes and edge-emitting lasers (EELs), such as low-divergence symmetric emission, wavelength stability, and inherent 2-D array fabrication. Improvements in reproducible highly efficient VCSELs have allowed VCSELs to be considered for high power and high brightness applications. In this talk, Aerius will discuss recent advances with Aerius' VCSELs and application of these VCSELs to miniature optical sensors such as rangefinders and illuminators.

  19. 8. High power laser and ignition facilities

    Bayramian, A.J.; Beach, R.J.; Bibeau, C.

    2002-01-01

    This document gives a review of the various high power laser projects and ignition facilities in the world: the Mercury laser system and Electra (Usa), the krypton fluoride (KrF) laser and the HALNA (high average power laser for nuclear-fusion application) project (Japan), the Shenguang series, the Xingguang facility and the TIL (technical integration line) facility (China), the Vulcan peta-watt interaction facility (UK), the Megajoule project and its feasibility phase: the LIL (laser integration line) facility (France), the Asterix IV/PALS high power laser facility (Czech Republic), and the Phelix project (Germany). In Japan the 100 TW Petawatt Module Laser, constructed in 1997, is being upgraded to the world biggest peta-watt laser. Experiments have been performed with single-pulse large aperture e-beam-pumped Garpun (Russia) and with high-current-density El-1 KrF laser installation (Russia) to investigate Al-Be foil transmittance and stability to multiple e-beam irradiations. An article is dedicated to a comparison of debris shield impacts for 2 experiments at NIF (national ignition facility). (A.C.)

  20. High Power UV LED Industrial Curing Systems

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  1. Implementing Molecular Dynamics for Hybrid High Performance Computers - 1. Short Range Forces

    Brown, W. Michael; Wang, Peng; Plimpton, Steven J.; Tharrington, Arnold N.

    2011-01-01

    The use of accelerators such as general-purpose graphics processing units (GPGPUs) have become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high performance computers, machines with more than one type of floating-point processor, are now becoming more prevalent due to these advantages. In this work, we discuss several important issues in porting a large molecular dynamics code for use on parallel hybrid machines - (1) choosing a hybrid parallel decomposition that works on central processing units (CPUs) with distributed memory and accelerator cores with shared memory, (2) minimizing the amount of code that must be ported for efficient acceleration, (3) utilizing the available processing power from both many-core CPUs and accelerators, and (4) choosing a programming model for acceleration. We present our solution to each of these issues for short-range force calculation in the molecular dynamics package LAMMPS. We describe algorithms for efficient short range force calculation on hybrid high performance machines. We describe a new approach for dynamic load balancing of work between CPU and accelerator cores. We describe the Geryon library that allows a single code to compile with both CUDA and OpenCL for use on a variety of accelerators. Finally, we present results on a parallel test cluster containing 32 Fermi GPGPUs and 180 CPU cores.

  2. Short term economic emission power scheduling of hydrothermal energy systems using improved water cycle algorithm

    Haroon, S.S.; Malik, T.N.

    2017-01-01

    Due to the increasing environmental concerns, the demand of clean and green energy and concern of atmospheric pollution is increasing. Hence, the power utilities are forced to limit their emissions within the prescribed limits. Therefore, the minimization of fuel cost as well as exhaust gas emissions is becoming an important and challenging task in the short-term scheduling of hydro-thermal energy systems. This paper proposes a novel algorithm known as WCA-ER (Water Cycle Algorithm with Evaporation Rate) to inspect the short term EEPSHES (Economic Emission Power Scheduling of Hydrothermal Energy Systems). WCA has its ancestries from the natural hydrologic cycle i.e. the raining process forms streams and these streams start flowing towards the rivers which finally flow towards the sea. The worth of WCA-ER has been tested on the standard economic emission power scheduling of hydrothermal energy test system consisting of four hydropower and three thermal plants. The problem has been investigated for the three case studies (i) ECS (Economic Cost Scheduling), (ii) ES (Economic Emission Scheduling) and (iii) ECES (Economic Cost and Emission Scheduling). The results obtained show that WCA-ER is superior to many other methods in the literature in bringing lower fuel cost and emissions. (author)

  3. Evaluating the quality of scenarios of short-term wind power generation

    Pinson, P.; Girard, R.

    2012-01-01

    Highlights: ► Presentation of the desirable properties of wind power generation scenarios. ► Description of various evaluation frameworks (univariate, multivariate, diagnostic). ► Highlighting of the properties of current approaches to scenario generation. ► Guidelines for future evaluation/benchmark exercises. -- Abstract: Scenarios of short-term wind power generation are becoming increasingly popular as input to multistage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benefits from their use in decision-making. So far however, their verification is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verification tools, as well as diagnostic approaches based on event-based verification are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools.

  4. The free recovery of a short duration, high current discharge

    Piejak, R.

    1984-01-01

    The hold-off voltage between stainless steel electrodes has been measured as a function of time after an initial discharge. The hold-off voltage is the highest voltage that the gap will withstand without appreciable current flow. A high current (600-1200 amp), short duration (170 nsec) discharge was initiated between Rogowski profile electrodes. After a pre-determined time delay, a second pulse was applied to the discharge gap. The hold-off voltage as a function to time was determined up to the Paschen breakdown voltage. Background gas pressure between 30 and 100 torr and electrode separation of 2mm and 4mm were employed. UV preionization was introduced in some tests to create various discharge modes (glow/arc). The findings indicate significantly higher recovery rates in air than in N 2 , presumably due to attachment processes. In addition, the presence of pre-breakdown UV was found to influence the discharge mode, thus affecting the recovery rate of the gap. Hold-off voltage curves for the previously mentioned gases, background pressures and electrode spacing will be presented along with open shutter photographs of the various discharge modes

  5. High speed micromachining with high power UV laser

    Patel, Rajesh S.; Bovatsek, James M.

    2013-03-01

    Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

  6. New high power linacs and beam physics

    Wangler, T.P.; Gray, E.R.; Nath, S.; Crandall, K.R.; Hasegawa, K.

    1997-01-01

    New high-power proton linacs must be designed to control beam loss, which can lead to radioactivation of the accelerator. The threat of beam loss is increased significantly by the formation of beam halo. Numerical simulation studies have identified the space-charge interactions, especially those that occur in rms mismatched beams, as a major concern for halo growth. The maximum-amplitude predictions of the simulation codes must be subjected to independent tests to confirm the validity of the results. Consequently, the authors compare predictions from the particle-core halo models with computer simulations to test their understanding of the halo mechanisms that are incorporated in the computer codes. They present and discuss scaling laws that provide guidance for high-power linac design

  7. The high-power iodine laser

    Brederlow, G.; Fill, E.; Witte, K. J.

    The book provides a description of the present state of the art concerning the iodine laser, giving particular attention to the design and operation of pulsed high-power iodine lasers. The basic features of the laser are examined, taking into account aspects of spontaneous emission lifetime, hyperfine structure, line broadening and line shifts, stimulated emission cross sections, the influence of magnetic fields, sublevel relaxation, the photodissociation of alkyl iodides, flashlamp technology, excitation in a direct discharge, chemical excitation, and questions regarding the chemical kinetics of the photodissociation iodine laser. The principles of high-power operation are considered along with aspects of beam quality and losses, the design and layout of an iodine laser system, the scalability and prospects of the iodine laser, and the design of the single-beam Asterix III laser.

  8. Industrial Applications of High Power Ultrasonics

    Patist, Alex; Bates, Darren

    Since the change of the millennium, high-power ultrasound has become an alternative food processing technology applicable to large-scale commercial applications such as emulsification, homogenization, extraction, crystallization, dewatering, low-temperature pasteurization, degassing, defoaming, activation and inactivation of enzymes, particle size reduction, extrusion, and viscosity alteration. This new focus can be attributed to significant improvements in equipment design and efficiency during the late 1990 s. Like most innovative food processing technologies, high-power ultrasonics is not an off-the-shelf technology, and thus requires careful development and scale-up for each and every application. The objective of this chapter is to present examples of ultrasonic applications that have been successful at the commercialization stage, advantages, and limitations, as well as key learnings from scaling up an innovative food technology in general.

  9. High power, repetitive stacked Blumlein pulse generators

    Davanloo, F; Borovina, D L; Korioth, J L; Krause, R K; Collins, C B [Univ. of Texas at Dallas, Richardson, TX (United States). Center for Quantum Electronics; Agee, F J [US Air Force Phillips Lab., Kirtland AFB, NM (United States); Kingsley, L E [US Army CECOM, Ft. Monmouth, NJ (United States)

    1997-12-31

    The repetitive stacked Blumlein pulse power generators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switch at the other end. In this way, relatively low charging voltages are multiplied to give a high discharge voltage across an arbitrary load. Extensive characterization of these novel pulsers have been performed over the past few years. Results indicate that they are capable of producing high power waveforms with rise times and repetition rates in the range of 0.5-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap, or photoconductive switch. The progress in the development and use of stacked Blumlein pulse generators is reviewed. The technology and the characteristics of these novel pulsers driving flash x-ray diodes are discussed. (author). 4 figs., 5 refs.

  10. Power Supplies for High Energy Particle Accelerators

    Dey, Pranab Kumar

    2016-06-01

    The on-going research and the development projects with Large Hadron Collider at CERN, Geneva, Switzerland has generated enormous enthusiasm and interest amongst all to know about the ultimate findings on `God's Particle'. This paper has made an attempt to unfold the power supply requirements and the methodology adopted to provide the stringent demand of such high energy particle accelerators during the initial stages of the search for the ultimate particles. An attempt has also been made to highlight the present status on the requirement of power supplies in some high energy accelerators with a view that, precautionary measures can be drawn during design and development from earlier experience which will be of help for the proposed third generation synchrotron to be installed in India at a huge cost.

  11. Comparative Study on KNN and SVM Based Weather Classification Models for Day Ahead Short Term Solar PV Power Forecasting

    Fei Wang

    2017-12-01

    Full Text Available Accurate solar photovoltaic (PV power forecasting is an essential tool for mitigating the negative effects caused by the uncertainty of PV output power in systems with high penetration levels of solar PV generation. Weather classification based modeling is an effective way to increase the accuracy of day-ahead short-term (DAST solar PV power forecasting because PV output power is strongly dependent on the specific weather conditions in a given time period. However, the accuracy of daily weather classification relies on both the applied classifiers and the training data. This paper aims to reveal how these two factors impact the classification performance and to delineate the relation between classification accuracy and sample dataset scale. Two commonly used classification methods, K-nearest neighbors (KNN and support vector machines (SVM are applied to classify the daily local weather types for DAST solar PV power forecasting using the operation data from a grid-connected PV plant in Hohhot, Inner Mongolia, China. We assessed the performance of SVM and KNN approaches, and then investigated the influences of sample scale, the number of categories, and the data distribution in different categories on the daily weather classification results. The simulation results illustrate that SVM performs well with small sample scale, while KNN is more sensitive to the length of the training dataset and can achieve higher accuracy than SVM with sufficient samples.

  12. High stability, high current DC-power supplies

    Hosono, K.; Hatanaka, K.; Itahashi, T.

    1995-01-01

    Improvements of the power supplies and the control system of the AVF cyclotron which is used as an injector to the ring cyclotron and of the transport system to the ring cyclotron were done in order to get more high quality and more stable beam. The power supply of the main coil of the AVF cyclotron was exchanged to new one. The old DCCTs (zero-flux current transformers) used for the power supplies of the trim coils of the AVF cyclotron were changed to new DCCTs to get more stability. The potentiometers used for the reference voltages in the other power supplies of the AVF cyclotron and the transport system were changed to the temperature controlled DAC method for numerical-value settings. This paper presents the results of the improvements. (author)

  13. Low Cost, Low Power, High Sensitivity Magnetometer

    2008-12-01

    which are used to measure the small magnetic signals from brain. Other types of vector magnetometers are fluxgate , coil based, and magnetoresistance...concentrator with the magnetometer currently used in Army multimodal sensor systems, the Brown fluxgate . One sees the MEMS fluxgate magnetometer is...Guedes, A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G

  14. Prospects for high-power radioactive beam facilities worldwide

    Nolen, Jerry A

    2003-01-01

    Advances in accelerators, targets, ion sources, and experimental instrumentation are making possible ever more powerful facilities for basic and applied research with short-lived radioactive isotopes. There are several current generation facilities, based on a variety of technologies, operating worldwide. These include, for example, those based on the in-flight method such as the recently upgraded National Superconducting Cyclotron Laboratory at Michigan State University, the facility at RIKEN in Japan, GANIL in Caen, France, and GSI in Darmstadt, Germany. Present facilities based on the Isotope-Separator On-Line method include, for example, the ISOLDE laboratory at CERN, HRIBF at Oak Ridge, and the new high-power facility ISAC at TRIUMF in Vancouver. Next-generation facilities include the Radioactive-Ion Factory upgrade of RIKEN to higher energy and intensity and the upgrade of ISAC to a higher energy secondary beam; both of these projects are in progress. A new project, LINAG, to upgrade the capabilities at...

  15. Advanced power flow technologies for high current ICF accelerators

    VanDevender, J.P.; McDaniel, D.H.

    1978-01-01

    Two new technologies for raising the power density in high current, inertial confinement fusion accelerators have been developed in the past two years. Magnetic flashover inhibition utilizes the self-magnetic fields around the vacuum insulator surface to inhibit surface flashover; average electric fields of 40 Mv/m at magnetic fields of 1.1 T have been achieved. Self-magnetic insulation of long, vacuum transmission lines has been used to transport power at 1.6 x 10 14 W/m 2 over six meters and up to 1.6 x 10 15 W/m 2 over short distances in a radial anode-cathode feed. The recent data relevant to these new technologies and their implications for ICF will be explored

  16. A survey of SiC power MOSFETs short-circuit robustness and failure mode analysis

    Ceccarelli, L.; Reigosa, P. D.; Iannuzzo, F.

    2017-01-01

    The aim of this paper is to provide an extensive overview about the state-of-art commercially available SiC power MOSFET, focusing on their short-circuit ruggedness. A detailed literature investigation has been carried out, in order to collect and understand the latest research contribution within...... this topic and create a survey of the present scenario of SiC MOSFETs reliability evaluation and failure mode analysis, pointing out the evolution and improvements as well as the future challenges in this promising device technology....

  17. Generation of statistical scenarios of short-term wind power production

    Pinson, Pierre; Papaefthymiou, George; Klockl, Bernd

    2007-01-01

    Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with a paramount information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform...... on the development of the forecast uncertainty through forecast series. This issue is addressed here by describing a method that permits to generate statistical scenarios of wind generation that accounts for the interdependence structure of prediction errors, in plus of respecting predictive distributions of wind...

  18. The long and short run forcing variables of purchasing power parity of ASEAN-5

    Abdalrahman AbuDalu; Elsadig Musa Ahmed

    2013-01-01

    This study examines the long-run and short-run forcing variables of purchasing power parity (PPP) for ASEAN-5 currencies vis-a-vis the U.S. dollar, i.e., their real effective exchange rate (REER). This study uses the autoregressive distributed lag (ARDL) approach to co-integration over the period 1991:Q1 – 2006:Q2. Our empirical results suggest that the domestic money supply (M1) is a significant long run forcing variable for the REERs of Malaysia, Indonesia, the Philippines, and Singapore. H...

  19. High-power planar dielectric waveguide lasers

    Shepherd, D.P.; Hettrick, S.J.; Li, C.; Mackenzie, J.I.; Beach, R.J.; Mitchell, S.C.; Meissner, H.E.

    2001-01-01

    The advantages and potential hazards of using a planar waveguide as the host in a high-power diode-pumped laser system are described. The techniques discussed include the use of proximity-coupled diodes, double-clad waveguides, unstable resonators, tapers, and integrated passive Q switches. Laser devices are described based on Yb 3+ -, Nd 3+ -, and Tm 3+ -doped YAG, and monolithic and highly compact waveguide lasers with outputs greater than 10 W are demonstrated. The prospects for scaling to the 100 W level and for further integration of devices for added functionality in a monolithic laser system are discussed. (author)

  20. Advances in high voltage power switching with GTOs

    Podlesak, T.F.

    1990-01-01

    The control of high voltage at high power, particularly opening switches, has been difficult in the past. Using gate turnoff thyristors (GTOs) arranged in series enables large currents to be switched at high voltage. The authors report a high voltage opening switch has been successfully demonstrated. This switch uses GTOs in series and successfully operates at voltages higher than the rated voltage of the individual devices. It is believed that this is the first time this has been successfully demonstrated, in that GTOs have been operated in series before, but always in a manner as to not exceed the voltage capability of the individual devices. In short, the devices have not worked together, sharing the voltage, but one device has been operated using several backup devices. Of particular interest is how well the individual devices share the voltage applied to them. Equal voltage sharing between devices is absolutely essential, in order to not exceed the voltage rating of any of the devices in the series chain. This is accomplished at high (microsecond) switching speeds. Thus, the system is useful for high frequency applications as well as high power, making for a flexible circuit system element. This demonstration system is rated at 5 KV and uses 1 KV devices. A larger 24 KV system is under design and will use 4.5 KV devices. In order to design the 24 KV switch, the safe operating area of the large devices must be known thoroughly

  1. Impact of steep-front short-duration impulse on electric power system insulation

    Burrage, L M; Veverka, E F; Shaw, J H [Cooper Industries, Inc., Franksville, WI (USA). Cooper Power Systems; McConnell, B W [Oak Ridge National Lab., TN (USA)

    1991-04-01

    This research effort required the performance evaluation of three specific insulation systems in common usage by electric power transmission and distribution utilities under stresses imposed by: three characteristic impulse waveforms (two waves representative of steep-front short duration (SFSD) impulses and one representative of lightning), the cumulative effect of multiple shots'' of each pulse, 60 Hz voltage, and, where appropriate, and mechanical load. The insulation systems evaluated are the cellulose-paper/oil combination typical of power transformer and condenser bushing usage, the cellulose-paper/enamel/oil combination used in distribution transformer construction, and the porcelain/air combination representing transmission and distribution line structural insulation. 4 refs., 94 figs., 11 tabs.

  2. Economic evaluation of short-term wind power forecast in ERCOT. Preliminary results

    Orwig, Kirsten D.; Hodge, Bri-Mathias; Brinkman, Greg; Ela, Erik; Milligan, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Banunarayanan, Venkat; Nasir, Saleh [ICF International, Fairfax, VA (United States); Freedman, Jeff [AWS Truepower, Albany, NY (United States)

    2012-07-01

    A number of wind energy integration studies have investigated the monetary value of using day-ahead wind power forecasts for grid operation decisions. Historically, these studies have shown that large cost savings could be gained by grid operators implementing the forecasts in their system operations. To date, none of these studies have investigated the value of shorter term (0- to 6-h ahead) wind power forecasts. In 2010, the Department of Energy and the National Oceanic and Atmospheric Administration partnered to form the Wind Forecasting Improvement Project (WFIP) to fund improvements in short-term wind forecasts and determine the economic value of these improvements to grid operators. In this work, we discuss the preliminary results of the economic benefit analysis portion of the WFIP for the Electric Reliability Council of Texas. The improvements seen in the wind forecasts are examined and the economic results of a production cost model simulation are analyzed. (orig.)

  3. High Energy Density Sciences with High Power Lasers at SACLA

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  4. High-power LEDs for plant cultivation

    Tamulaitis, Gintautas; Duchovskis, Pavelas; Bliznikas, Zenius; Breive, Kestutis; Ulinskaite, Raimonda; Brazaityte, Ausra; Novickovas, Algirdas; Zukauskas, Arturas; Shur, Michael S.

    2004-10-01

    We report on high-power solid-state lighting facility for cultivation of greenhouse vegetables and on the results of the study of control of photosynthetic activity and growth morphology of radish and lettuce imposed by variation of the spectral composition of illumination. Experimental lighting modules (useful area of 0.22 m2) were designed based on 4 types of high-power light-emitting diodes (LEDs) with emission peaked in red at the wavelengths of 660 nm and 640 nm (predominantly absorbed by chlorophyll a and b for photosynthesis, respectively), in blue at 455 nm (phototropic function), and in far-red at 735 nm (important for photomorphology). Morphological characteristics, chlorophyll and phytohormone concentrations in radish and lettuce grown in phytotron chambers under lighting with different spectral composition of the LED-based illuminator and under illumination by high pressure sodium lamps with an equivalent photosynthetic photon flux density were compared. A well-balanced solid-state lighting was found to enhance production of green mass and to ensure healthy morphogenesis of plants compared to those grown using conventional lighting. We observed that the plant morphology and concentrations of morphologically active phytohormones is strongly affected by the spectral composition of light in the red region. Commercial application of the LED-based illumination for large-scale plant cultivation is discussed. This technology is favorable from the point of view of energy consumption, controllable growth, and food safety but is hindered by high cost of the LEDs. Large scale manufacturing of high-power red AlInGaP-based LEDs emitting at 650 nm and a further decrease of the photon price for the LEDs emitting in the vicinity of the absorption peak of chlorophylls have to be achieved to promote horticulture applications.

  5. Industrial Applications of High Average Power FELS

    Shinn, Michelle D

    2005-01-01

    The use of lasers for material processing continues to expand, and the annual sales of such lasers exceeds $1 B (US). Large scale (many m2) processing of materials require the economical production of laser powers of the tens of kilowatts, and therefore are not yet commercial processes, although they have been demonstrated. The development of FELs based on superconducting RF (SRF) linac technology provides a scaleable path to laser outputs above 50 kW in the IR, rendering these applications economically viable, since the cost/photon drops as the output power increases. This approach also enables high average power ~ 1 kW output in the UV spectrum. Such FELs will provide quasi-cw (PRFs in the tens of MHz), of ultrafast (pulsewidth ~ 1 ps) output with very high beam quality. This talk will provide an overview of applications tests by our facility's users such as pulsed laser deposition, laser ablation, and laser surface modification, as well as present plans that will be tested with our upgraded FELs. These upg...

  6. Reducing the Risk of Damage to Power Transformers of 110 kV and Above Accompanying Internal Short Circuits

    L’vova, M. M. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); L’vov, S. Yu. [Presselektro LLC (Russian Federation); Komarov, V. B. [IPCE RAS (Russian Federation); Lyut’ko, E. O. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); Vdoviko, V. P. [EMA Ltd. (Russian Federation); Demchenko, V. V. [JSC “Boguchanskaya HPP” (Russian Federation); Belyaev, S. G. [PKF Konif Ltd. (Russian Federation); Savel’ev, V. A. [Ivanovo State Power University (Russian Federation); L’vov, M. Yu., E-mail: timashova@nte-power.ru; L’vov, Yu. N. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation)

    2015-03-15

    Methods of increasing the operating reliability of power transformers, autotransformers and shunting reactors in order to reduce the risk of damage, which accompany internal short circuits and equipment fires and explosions, are considered.

  7. Industrial application of high power disk lasers

    Brockmann, Rüdiger; Havrilla, David

    2008-02-01

    Laser welding has become one of the fastest growing areas for industrial laser applications. The increasing cost effectiveness of the laser process is enabled by the development of new highly efficient laser sources, such as the Disk laser, coupled with decreasing cost per Watt. TRUMPF introduced the Disk laser several years ago, and today it has become the most reliable laser tool on the market. The excellent beam quality and output powers of up to 10 kW enable its application in the automotive industry as well as in the range of thick plate welding, such as heavy construction and ship building. This serves as an overview of the most recent developments on the TRUMPF Disk laser and its industrial applications like cutting, welding, remote welding and hybrid welding, too. The future prospects regarding increased power and even further improved productivity and economics are presented.

  8. High-field, high-density tokamak power reactor

    Cohn, D.R.; Cook, D.L.; Hay, R.D.; Kaplan, D.; Kreischer, K.; Lidskii, L.M.; Stephany, W.; Williams, J.E.C.; Jassby, D.L.; Okabayashi, M.

    1977-11-01

    A conceptual design of a compact (R 0 = 6.0 m) high power density (average P/sub f/ = 7.7 MW/m 3 ) tokamak demonstration power reactor has been developed. High magnetic field (B/sub t/ = 7.4 T) and moderate elongation (b/a = 1.6) permit operation at the high density (n(0) approximately 5 x 10 14 cm -3 ) needed for ignition in a relatively small plasma, with a spatially-averaged toroidal beta of only 4%. A unique design for the Nb 3 Sn toroidal-field magnet system reduces the stress in the high-field trunk region, and allows modularization for simpler disassembly. The modest value of toroidal beta permits a simple, modularized plasma-shaping coil system, located inside the TF coil trunk. Heating of the dense central plasma is attained by the use of ripple-assisted injection of 120-keV D 0 beams. The ripple-coil system also affords dynamic control of the plasma temperature during the burn period. A FLIBE-lithium blanket is designed especially for high-power-density operation in a high-field environment, and gives an overall tritium breeding ratio of 1.05 in the slowly pumped lithium

  9. The JLab high power ERL light source

    Neil, G.R.; Behre, C.; Benson, S.V.

    2006-01-01

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered (superconducting) Linac (ERL). The machine has a 160MeV electron beam and an average current of 10mA in 75MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz ∼ half cycle pulse whose average brightness is >5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20W of average power extracted [Carr, et al., Nature 420 (2002) 153]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100fs pulses with >200W of average power. The FELs also provide record-breaking laser power [Neil, et al., Phys. Rev. Lett. 84 (2000) 662]: up to 10kW of average power in the IR from 1 to 14μm in 400fs pulses at up to 74.85MHz repetition rates and soon will produce similar pulses of 300-1000nm light at up to 3kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10ms long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and

  10. The JLab high power ERL light source

    G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

    2005-03-19

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made

  11. High peak power tubes and gate effect Klystrons

    Gerbelot, N.; Bres, M.; Faillon, G.; Buzzi, J.M.

    1993-01-01

    The conventional microwave tubes such as TWTs, Magnetrons, Klystrons... deliver the very high peak powers which are required by radar transmitters but more especially by many particle accelerators. In the range of a few hundred MHz to about 10 GHz, some dozen of MWs per unit are currently obtained and commercially available, according to the frequency and the pulse lengths. But peak power requirements are ever increasing, especially for the expected new linear particle acceleratores, where several hundred MWs per tube would be necessary. Also some special military transmitters begin to request GW pulses, with short pulse lengths - of course - but at nonnegligible repetition rates. Therefore several laboratories and microwave vacuum tube manufacturers have engaged - for several years - studies and development in the field of very high peak microwave power (HPM) toward two main directions: extended operation and extrapolation of the conventional tubes and devices; development of new concepts, among which the most promising are likely the high-current relativistic klystrons - that are also referred to as gate effect klystrons

  12. Swarm Intelligence-Based Hybrid Models for Short-Term Power Load Prediction

    Jianzhou Wang

    2014-01-01

    Full Text Available Swarm intelligence (SI is widely and successfully applied in the engineering field to solve practical optimization problems because various hybrid models, which are based on the SI algorithm and statistical models, are developed to further improve the predictive abilities. In this paper, hybrid intelligent forecasting models based on the cuckoo search (CS as well as the singular spectrum analysis (SSA, time series, and machine learning methods are proposed to conduct short-term power load prediction. The forecasting performance of the proposed models is augmented by a rolling multistep strategy over the prediction horizon. The test results are representative of the out-performance of the SSA and CS in tuning the seasonal autoregressive integrated moving average (SARIMA and support vector regression (SVR in improving load forecasting, which indicates that both the SSA-based data denoising and SI-based intelligent optimization strategy can effectively improve the model’s predictive performance. Additionally, the proposed CS-SSA-SARIMA and CS-SSA-SVR models provide very impressive forecasting results, demonstrating their strong robustness and universal forecasting capacities in terms of short-term power load prediction 24 hours in advance.

  13. Approaching Repetitive Short Circuit Tests on MW-Scale Power Modules by means of an Automatic Testing Setup

    Reigosa, Paula Diaz; Wang, Huai; Iannuzzo, Francesco

    2016-01-01

    An automatic testing system to perform repetitive short-circuit tests on megawatt-scale IGBT power modules is pre-sented and described in this paper, pointing out the advantages and features of such testing approach. The developed system is based on a non-destructive short-circuit tester, which has...

  14. Several problems of algorithmization in integrated computation programs on third generation computers for short circuit currents in complex power networks

    Krylov, V.A.; Pisarenko, V.P.

    1982-01-01

    Methods of modeling complex power networks with short circuits in the networks are described. The methods are implemented in integrated computation programs for short circuit currents and equivalents in electrical networks with a large number of branch points (up to 1000) on a computer with a limited on line memory capacity (M equals 4030 for the computer).

  15. ACE DD genotype is unfavorable to Korean short-term muscle power athletes.

    Kim, C-H; Cho, J-Y; Jeon, J Y; Koh, Y G; Kim, Y-M; Kim, H-J; Park, M; Um, H-S; Kim, C

    2010-01-01

    The purpose of this study was to test the hypothesis that the ACE DD genotype is unfavorably associated with the ultimate power-oriented performance. To test the hypothesis we recruited a total of 848 subjects including 55 international level power-oriented athletes (High-performance), 100 national level power-oriented athletes (Mid-performance) and 693 healthy controls (Control) in Korea. Then the distributions of ACE polymorphism throughout these groups were analyzed. As a result, there was a gradual decrease of frequencies of the DD genotype with advancing levels of performance (Control vs. Mid-performance vs. High-performance=17.2% vs. 10.0% vs. 5.5%, p=0.002). Also, the frequencies of D allele decreased gradually with advancing levels of performance (Control vs. Mid-performance vs. High-performance=42.6% vs. 35.0% vs. 30.9%, pDD genotype and the D allele. This finding gave 3.83 times lower probability of success in power-oriented sports for individuals with the DD genotype than those with the II+ ID genotype. In conclusion, these results indicate that Korean power-oriented athletes with a lower frequency of the DD genotype had a lower probability of success in power-oriented sports. Georg Thieme Verlag KG Stuttgart, New York.

  16. Analog Circuit Design Low Voltage Low Power; Short Range Wireless Front-Ends; Power Management and DC-DC

    Roermund, Arthur; Baschirotto, Andrea

    2012-01-01

    The book contains the contribution of 18 tutorials of the 20th workshop on Advances in Analog Circuit Design.  Each part discusses a specific to-date topic on new and valuable design ideas in the area of analog circuit design. Each part is presented by six experts in that field and state of the art information is shared and overviewed. This book is number 20 in this successful series of Analog Circuit Design, providing valuable information and excellent overviews of Low-Voltage Low-Power Data Converters - Chaired by Prof. Anderea Baschirotto, University of Milan-Bicocca Short Range Wireless Front-Ends - Chaired by Prof. Arthur van Roermund, Eindhoven University of Technology Power management and DC-DC - Chaired by Prof. M. Steyaert, Katholieke University Leuven Analog Circuit Design is an essential reference source for analog circuit designers and researchers wishing to keep abreast with the latest development in the field. The tutorial coverage also makes it suitable for use in an advanced design.

  17. Application of high power microwave vacuum electron devices

    Ding Yaogen; Liu Pukun; Zhang Zhaochuan; Wang Yong; Shen Bin

    2011-01-01

    High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

  18. Feasibility study of superconducting power cables for DC electric railway feeding systems in view of thermal condition at short circuit accident

    Kumagai, Daisuke; Ohsaki, Hiroyuki; Tomita, Masaru

    2016-12-01

    A superconducting power cable has merits of a high power transmission capacity, transmission losses reduction, a compactness, etc., therefore, we have been studying the feasibility of applying superconducting power cables to DC electric railway feeding systems. However, a superconducting power cable is required to be cooled down and kept at a very low temperature, so it is important to reveal its thermal and cooling characteristics. In this study, electric circuit analysis models of the system and thermal analysis models of superconducting cables were constructed and the system behaviors were simulated. We analyzed the heat generation by a short circuit accident and transient temperature distribution of the cable to estimate the value of temperature rise and the time required from the accident. From these results, we discussed a feasibility of superconducting cables for DC electric railway feeding systems. The results showed that the short circuit accident had little impact on the thermal condition of a superconducting cable in the installed system.

  19. Novel miniature high power ring filter

    Huang Huifen; Mao Junfa; Luo Zhihua

    2005-01-01

    The power handling capability of high temperature superconducting (HTS) filters is limited due to current concentration at the edges of the superconducting films. This problem can be overcome by using ring resonator, which employs the edge current free and reduces the current concentration. However, this kind of filter has large size. In order to reduce the cost and size and increase the power handling capability, in this paper a HTS photonic bandgap (PBG) structure filter is developed. The proposed pass band filter with PBG structure exhibits center frequency 12.23 GHz, steepness (about 35 dB/GHz), bandwidth (-3 dB bandwidth is 0.045 GHz), and low insertion loss (about -0.5 dB), and can handle input power up to 1 W (this value was limited by the measurement instrument used in the experiment). The size is reduced by 25%, insertion loss reduced by 37.5%, and steeper roll-off of the filter is also obtained compared with that in published literature

  20. OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

    Medhin, Ashenafi Kiros

    This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra...

  1. High-power converters and AC drives

    Wu, Bin

    2017-01-01

    This new edition reflects the recent technological advancements in the MV drive industry, such as advanced multilevel converters and drive configurations. It includes three new chapters, Control of Synchronous Motor Drives, Transformerless MV Drives, and Matrix Converter Fed Drives. In addition, there are extensively revised chapters on Multilevel Voltage Source Inverters and Voltage Source Inverter-Fed Drives. This book includes a systematic analysis on a variety of high-power multilevel converters, illustrates important concepts with simulations and experiments, introduces various megawatt drives produced by world leading drive manufacturers, and addresses practical problems and their mitigations methods.

  2. Compulsator, a high power compensated pulsed alternator

    Weldon, W.F.; Bird, W.L.; Driga, M.D.; Rylander, H.G.; Tolk, K.M.; Woodson, H.H.

    1983-01-01

    This chapter describes a pulsed power supply utilizing inertial energy storage as a possible replacement for large capacitor banks. The compulsator overcomes many of the limitations of the pulsed homopolar generators previously developed by the Center for Electromechanics and elsewhere in that it offers high voltage (10's of kV) and consequently higher pulse rise times, is self commutating, and offers the possibility of generating repetitive pulses. The compulsator converts rotational inertial energy directly into electrical energy utilizing the principles of both magnetic induction and flux compression. The theory of operation, a prototype compulsator design, and advanced compulsator designs are discussed

  3. Cost optimisation studies of high power accelerators

    McAdams, R.; Nightingale, M.P.S.; Godden, D. [AEA Technology, Oxon (United Kingdom)] [and others

    1995-10-01

    Cost optimisation studies are carried out for an accelerator based neutron source consisting of a series of linear accelerators. The characteristics of the lowest cost design for a given beam current and energy machine such as power and length are found to depend on the lifetime envisaged for it. For a fixed neutron yield it is preferable to have a low current, high energy machine. The benefits of superconducting technology are also investigated. A Separated Orbit Cyclotron (SOC) has the potential to reduce capital and operating costs and intial estimates for the transverse and longitudinal current limits of such machines are made.

  4. Short-Term Wind Electric Power Forecasting Using a Novel Multi-Stage Intelligent Algorithm

    Haoran Zhao

    2018-03-01

    Full Text Available As the most efficient renewable energy source for generating electricity in a modern electricity network, wind power has the potential to realize sustainable energy supply. However, owing to its random and intermittent instincts, a high permeability of wind power into a power network demands accurate and effective wind energy prediction models. This study proposes a multi-stage intelligent algorithm for wind electric power prediction, which combines the Beveridge–Nelson (B-N decomposition approach, the Least Square Support Vector Machine (LSSVM, and a newly proposed intelligent optimization approach called the Grasshopper Optimization Algorithm (GOA. For data preprocessing, the B-N decomposition approach was employed to disintegrate the hourly wind electric power data into a deterministic trend, a cyclic term, and a random component. Then, the LSSVM optimized by the GOA (denoted GOA-LSSVM was applied to forecast the future 168 h of the deterministic trend, the cyclic term, and the stochastic component, respectively. Finally, the future hourly wind electric power values can be obtained by multiplying the forecasted values of these three trends. Through comparing the forecasting performance of this proposed method with the LSSVM, the LSSVM optimized by the Fruit-fly Optimization Algorithm (FOA-LSSVM, and the LSSVM optimized by Particle Swarm Optimization (PSO-LSSVM, it is verified that the established multi-stage approach is superior to other models and can increase the precision of wind electric power prediction effectively.

  5. Reliability of high power electron accelerators for radiation processing

    Zimek, Z.

    2011-01-01

    Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

  6. Reliability of high power electron accelerators for radiation processing

    Zimek, Z. [Department of Radiation Chemistry and Technology, Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Accelerators applied for radiation processing are installed in industrial facilities where accelerator availability coefficient should be at the level of 95% to fulfill requirements according to industry standards. Usually the exploitation of electron accelerator reviles the number of short and few long lasting failures. Some technical shortages can be overcome by practical implementation the experience gained in accelerator technology development by different accelerator manufactures. The reliability/availability of high power accelerators for application in flue gas treatment process must be dramatically improved to meet industrial standards. Support of accelerator technology dedicated for environment protection should be provided by governmental and international institutions to overcome accelerator reliability/availability problem and high risk and low direct profit in this particular application. (author)

  7. An Optimized Prediction Intervals Approach for Short Term PV Power Forecasting

    Qiang Ni

    2017-10-01

    Full Text Available High quality photovoltaic (PV power prediction intervals (PIs are essential to power system operation and planning. To improve the reliability and sharpness of PIs, in this paper, a new method is proposed, which involves the model uncertainties and noise uncertainties, and PIs are constructed with a two-step formulation. In the first step, the variance of model uncertainties is obtained by using extreme learning machine to make deterministic forecasts of PV power. In the second stage, innovative PI-based cost function is developed to optimize the parameters of ELM and noise uncertainties are quantization in terms of variance. The performance of the proposed approach is examined by using the PV power and meteorological data measured from 1kW rooftop DC micro-grid system. The validity of the proposed method is verified by comparing the experimental analysis with other benchmarking methods, and the results exhibit a superior performance.

  8. INFLUENCE OF RAMADAN FASTING ON ANAEROBIC PERFORMANCE AND RECOVERY FOLLOWING SHORT TIME HIGH INTENSITY EXERCISE

    Umid Karli

    2007-12-01

    Full Text Available The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 ± 1.25 yr participated in this study. The subjects were tested three times [3 days before the beginning of Ramadan (Pre-RF, the last 3 days of Ramadan (End-RF and the last 3 days of the 4th week after the end of Ramadan (After-RF]. Anaerobic power and capacity were measured by using the Wingate Anaerobic Test (WAnT at Pre-RF, End-RF and After- RF. Capillary blood samples for lactate analyses and heart rate recordings were taken at rest, immediately after WAnT and throughout the recovery period. Repeated measures of ANOVA indicated that there were no significant changes in body weight, body mass index, fat free mass, percentage of body fat, daily sleeping time and daily caloric intake associated with Ramadan fasting. No significant changes were found in total body water either, but urinary density measured at End-RF was significantly higher than After-RF. Similarity among peak HR and peak LA values at Pre-RF, End- RF and After-RF demonstrated that cardiovascular and metabolic stress caused by WAnT was not affected by Ramadan fasting. In addition, no influence of Ramadan fasting on anaerobic power and capacity and removal rate of LA from blood following high intensity exercise was observed. The results of this study revealed that if strength-power training is performed regularly and daily food intake, body fluid balance and daily sleeping time are maintained as before Ramadan, Ramadan fasting will not have adverse effects on body composition, anaerobic power and capacity, and LA metabolism during and after high intensity exercise in power athletes

  9. An Advanced Bayesian Method for Short-Term Probabilistic Forecasting of the Generation of Wind Power

    Antonio Bracale

    2015-09-01

    Full Text Available Currently, among renewable distributed generation systems, wind generators are receiving a great deal of interest due to the great economic, technological, and environmental incentives they involve. However, the uncertainties due to the intermittent nature of wind energy make it difficult to operate electrical power systems optimally and make decisions that satisfy the needs of all the stakeholders of the electricity energy market. Thus, there is increasing interest determining how to forecast wind power production accurately. Most the methods that have been published in the relevant literature provided deterministic forecasts even though great interest has been focused recently on probabilistic forecast methods. In this paper, an advanced probabilistic method is proposed for short-term forecasting of wind power production. A mixture of two Weibull distributions was used as a probability function to model the uncertainties associated with wind speed. Then, a Bayesian inference approach with a particularly-effective, autoregressive, integrated, moving-average model was used to determine the parameters of the mixture Weibull distribution. Numerical applications also are presented to provide evidence of the forecasting performance of the Bayesian-based approach.

  10. High-Power Ion Thruster Technology

    Beattie, J. R.; Matossian, J. N.

    1996-01-01

    Performance data are presented for the NASA/Hughes 30-cm-diam 'common' thruster operated over the power range from 600 W to 4.6 kW. At the 4.6-kW power level, the thruster produces 172 mN of thrust at a specific impulse of just under 4000 s. Xenon pressure and temperature measurements are presented for a 6.4-mm-diam hollow cathode operated at emission currents ranging from 5 to 30 A and flow rates of 4 sccm and 8 sccm. Highly reproducible results show that the cathode temperature is a linear function of emission current, ranging from approx. 1000 C to 1150 C over this same current range. Laser-induced fluorescence (LIF) measurements obtained from a 30-cm-diam thruster are presented, suggesting that LIF could be a valuable diagnostic for real-time assessment of accelerator-arid erosion. Calibration results of laminar-thin-film (LTF) erosion badges with bulk molybdenum are presented for 300-eV xenon, krypton, and argon sputtering ions. Facility-pressure effects on the charge-exchange ion current collected by 8-cm-diam and 30-cm-diam thrusters operated on xenon propellant are presented to show that accel current is nearly independent of facility pressure at low pressures, but increases rapidly under high-background-pressure conditions.

  11. Utilisation of symmetrical components in a communication-based protection for loop MV feeders with variable short-circuit power

    Ciontea, Catalin-Iosif; Bak, Claus Leth; Blaabjerg, Frede

    2018-01-01

    -circuit power is presented. It relies on utilisation of symmetrical components of the short-circuit currents and on communication between the protection relays. The proposed method addresses the Single Phase to Ground (SPG) faults occurring in directly grounded distribution networks, with focus on closed......Variability of the available short-circuit power also implies variation of the fault level, which can potentially cause several protection problems in the electric networks. In this paper, a novel protection method that is insensitive to the fault level changes caused by variable short......-loop Medium Voltage (MV) feeders. Case studies are presented, which demonstrate that the proposed protection scheme is capable of effectively detecting the SPG faults in closed-loop feeders with variable short-circuit power....

  12. Short-circuit experiments on a high Tc-superconducting cable conductor

    Tønnesen, Ole; Jensen, E.H.; Traholt, C.

    2002-01-01

    A high temperature superconductor (HTS) cable conductor (CC) with a critical current of 2.1 kA was tested over a range of short-circuit currents up to 20 kA. The duration of the short-circuit currents is 1 s. Between each short-circuit test the critical current of the HTS CC was measured in order...

  13. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    2010-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When operating...

  14. Optimal Operation of Plug-In Electric Vehicles in Power Systems with High Wind Power Penetrations

    Hu, Weihao; Su, Chi; Chen, Zhe

    2013-01-01

    in the power systems with high wind power penetrations. In this paper, the integration of plug-in electric vehicles in the power systems with high wind power penetrations is proposed and discussed. Optimal operation strategies of PEV in the spot market are proposed in order to decrease the energy cost for PEV......The Danish power system has a large penetration of wind power. The wind fluctuation causes a high variation in the power generation, which must be balanced by other sources. The battery storage based Plug-In Electric Vehicles (PEV) may be a possible solution to balance the wind power variations...... owners. Furthermore, the application of battery storage based aggregated PEV is analyzed as a regulation services provider in the power system with high wind power penetrations. The western Danish power system where the total share of annual wind power production is more than 27% of the electrical energy...

  15. Medium and Short Wave RF Energy Harvester for Powering Wireless Sensor Networks.

    Leon-Gil, Jesus A; Cortes-Loredo, Agustin; Fabian-Mijangos, Angel; Martinez-Flores, Javier J; Tovar-Padilla, Marco; Cardona-Castro, M Antonia; Morales-Sánchez, Alfredo; Alvarez-Quintana, Jaime

    2018-03-03

    Internet of Things (IoT) is an emerging platform in which every day physical objects provided with unique identifiers are connected to the Internet without requiring human interaction. The possibilities of such a connected world enables new forms of automation to make our lives easier and safer. Evidently, in order to keep billions of these communicating devices powered long-term, a self-sustainable operation is a key point for realization of such a complex network. In this sense, energy-harvesting technologies combined with low power consumption ICs eliminate the need for batteries, removing an obstacle to the success of the IoT. In this work, a Radio Frequency (RF) energy harvester tuned at AM broadcast has been developed for low consumption power devices. The AM signals from ambient are detected via a high-performance antenna-free LC circuit with an efficiency of 3.2%. To maximize energy scavenging, the RF-DC conversion stage is based on a full-wave Cockcroft-Walton voltage multiplier (CWVM) with efficiency up to 90%. System performance is evaluated by rating the maximum power delivered into the load via its output impedance, which is around 62 μW, although power level seems to be low, it is able to power up low consumption devices such as Leds, portable calculators and weather monitoring stations.

  16. An analog ensemble for short-term probabilistic solar power forecast

    Alessandrini, S.; Delle Monache, L.; Sperati, S.; Cervone, G.

    2015-01-01

    Highlights: • A novel method for solar power probabilistic forecasting is proposed. • The forecast accuracy does not depend on the nominal power. • The impact of climatology on forecast accuracy is evaluated. - Abstract: The energy produced by photovoltaic farms has a variable nature depending on astronomical and meteorological factors. The former are the solar elevation and the solar azimuth, which are easily predictable without any uncertainty. The amount of liquid water met by the solar radiation within the troposphere is the main meteorological factor influencing the solar power production, as a fraction of short wave solar radiation is reflected by the water particles and cannot reach the earth surface. The total cloud cover is a meteorological variable often used to indicate the presence of liquid water in the troposphere and has a limited predictability, which is also reflected on the global horizontal irradiance and, as a consequence, on solar photovoltaic power prediction. This lack of predictability makes the solar energy integration into the grid challenging. A cost-effective utilization of solar energy over a grid strongly depends on the accuracy and reliability of the power forecasts available to the Transmission System Operators (TSOs). Furthermore, several countries have in place legislation requiring solar power producers to pay penalties proportional to the errors of day-ahead energy forecasts, which makes the accuracy of such predictions a determining factor for producers to reduce their economic losses. Probabilistic predictions can provide accurate deterministic forecasts along with a quantification of their uncertainty, as well as a reliable estimate of the probability to overcome a certain production threshold. In this paper we propose the application of an analog ensemble (AnEn) method to generate probabilistic solar power forecasts (SPF). The AnEn is based on an historical set of deterministic numerical weather prediction (NWP) model

  17. Short-term electric power demand forecasting based on economic-electricity transmission model

    Li, Wenfeng; Bai, Hongkun; Liu, Wei; Liu, Yongmin; Wang, Yubin Mao; Wang, Jiangbo; He, Dandan

    2018-04-01

    Short-term electricity demand forecasting is the basic work to ensure safe operation of the power system. In this paper, a practical economic electricity transmission model (EETM) is built. With the intelligent adaptive modeling capabilities of Prognoz Platform 7.2, the econometric model consists of three industrial added value and income levels is firstly built, the electricity demand transmission model is also built. By multiple regression, moving averages and seasonal decomposition, the problem of multiple correlations between variables is effectively overcome in EETM. The validity of EETM is proved by comparison with the actual value of Henan Province. Finally, EETM model is used to forecast the electricity consumption of the 1-4 quarter of 2018.

  18. Nonlinear interaction of powerful short electromagnetic pulses with an electron plasma

    Rao, N.N.; Yu, M.Y.; Shukla, P.K.

    1990-01-01

    The nonlinear interaction of powerful short electromagnetic pulses with a plasma consisting of two groups of electrons and immobile ions has been studied. It is shown that the interaction is governed by a nonlinear equation for the electromagnetic wave envelope and a driven nonlinear equation for the low-frequency electron fluctuations. The driver for the latter depends explicitly on the spatio-temporal evolution of the electromagnetic wave flux. It is found that, depending on the cold-to-hot electron density ratio, the localized pulse can propagate with sub- as well as supersonic velocities accompanied by compressional or rarefactional density perturbations. The conditions of existence for the different types of solitary pulses are obtained. The present investigation may be relevant to the study of wave-plasma interaction devices such as inertial fusion confinement as well as to ionospheric modification experiments. (author)

  19. Adaptive short-term electricity price forecasting using artificial neural networks in the restructured power markets

    Yamin, H.Y.; Shahidehpour, S.M.; Li, Z.

    2004-01-01

    This paper proposes a comprehensive model for the adaptive short-term electricity price forecasting using Artificial Neural Networks (ANN) in the restructured power markets. The model consists: price simulation, price forecasting, and performance analysis. The factors impacting the electricity price forecasting, including time factors, load factors, reserve factors, and historical price factor are discussed. We adopted ANN and proposed a new definition for the MAPE using the median to study the relationship between these factors and market price as well as the performance of the electricity price forecasting. The reserve factors are included to enhance the performance of the forecasting process. The proposed model handles the price spikes more efficiently due to considering the median instead of the average. The IEEE 118-bus system and California practical system are used to demonstrate the superiority of the proposed model. (author)

  20. New configurations for short-pulses high power solid-state lasers: conception and realization of highly doped waveguide amplifiers/lasers grown by liquid phase epitaxy and demonstration of Y2SiO5: Yb and Lu2SiO5: Yb femtosecond lasers

    Thibault, F.

    2006-04-01

    Yb-doped yttrium and lutetium ortho-silicates, Y 2 SiO 5 :Yb and Lu 2 SiO 5 :Yb respectively, exhibit spectroscopic properties favorable to an efficient laser operation in both high power cw and femtosecond regime. Their first diode-pumped femtosecond operation demonstration lead to exceptional performances in terms of output power and efficiency. In order to realize compact and efficient solid-state laser devices using those materials, we chose a configuration with an Yb-doped medium planar waveguide geometry, grown by liquid phase epitaxy, face-pumped by a single laser diode bar. The growth of highly doped Y 2 SiO 5 :Yb layers, within a large range of compositions and thicknesses, was demonstrated. The refractive index increase due to the substitution of the various dopants is analyzed. The layers spectroscopic properties are similar to the bulk ones, with an noticeably higher crystalline quality. The Yb ion lifetime evolution with respect to its doping shows up a particularly low decrease, proof of a low concentration of extrinsic quenching centers. The covered YSO:24%Yb waveguides exhibit lower than 0.3 dB/cm propagation losses, and provided up to 2.9 dB/cm net amplification at 1082 nm with a single mode output. The realization of the first diode-pumped monolithic cw waveguide lasers was also demonstrated. For a 4% output coupler, they provided up to 340 mW at 1082 nm with a 14% slope efficiency. (author)

  1. High power diode laser remelting of metals

    Chmelickova, H; Tomastik, J; Ctvrtlik, R; Supik, J; Nemecek, S; Misek, M

    2014-01-01

    This article is focused on the laser surface remelting of the steel samples with predefined overlapping of the laser spots. The goal of our experimental work was to evaluate microstructure and hardness both in overlapped zone and single pass ones for three kinds of ferrous metals with different content of carbon, cast iron, non-alloy structural steel and tool steel. High power fibre coupled diode laser Laserline LDF 3600-100 was used with robotic guided processing head equipped by the laser beam homogenizer that creates rectangular beam shape with uniform intensity distribution. Each sample was treated with identical process parameters - laser power, beam diameter, focus position, speed of motion and 40% spot overlap. Dimensions and structures of the remelted zone, zone of the partial melting, heat affected zone and base material were detected and measured by means of laser scanning and optical microscopes. Hardness progress in the vertical axis of the overlapped zone from remelted surface layer to base material was measured and compared with the hardness of the single spots. The most hardness growth was found for cast iron, the least for structural steel. Experiment results will be used to processing parameters optimization for each tested material separately.

  2. High resolving power spectrometer for beam analysis

    Moshammer, H.W.; Spencer, J.E.

    1992-03-01

    We describe a system designed to analyze the high energy, closely spaced bunches from individual RF pulses. Neither a large solid angle nor momentum range is required so this allows characteristics that appear useful for other applications such as ion beam lithography. The spectrometer is a compact, double-focusing QBQ design whose symmetry allows the Quads to range between F or D with a correspondingly large range of magnifications, dispersion and resolving power. This flexibility insures the possibility of spatially separating all of the bunches along the focal plane with minimal transverse kicks and bending angle for differing input conditions. The symmetry of the system allows a simple geometric interpretationof the resolving power in terms of thin lenses and ray optics. We discuss the optics and the hardware that is proposed to measure emittance, energy, energy spread and bunch length for each bunch in an RF pulse train for small bunch separations. We also discuss how to use such measurements for feedback and feedforward control of these bunch characteristics as well as maintain their stability. 2 refs

  3. Improved Collectors for High Power Gyrotrons

    Ives, R. Lawrence; Singh, Amarjit; Read, Michael; Borchard, Philipp; Neilson, Jeff

    2009-01-01

    High power gyrotrons are used for electron cyclotron heating, current drive and parasitic mode suppression in tokamaks for fusion energy research. These devices are crucial for successful operation of many research programs around the world, including the ITER program currently being constructed in France. Recent gyrotron failures resulted from cyclic fatigue of the copper material used to fabricated the collectors. The techniques used to collect the spent beam power is common in many gyrotrons produced around the world. There is serious concern that these tubes may also be at risk from cyclic fatigue. This program addresses the cause of the collector failure. The Phase I program successfully demonstrated feasibility of a mode of operation that eliminates the cyclic operation that caused the failure. It also demonstrated that new material can provide increased lifetime under cyclic operation that could increase the lifetime by more than on order of magnitude. The Phase II program will complete that research and develop a collector that eliminates the fatigue failures. Such a design would find application around the world.

  4. Modelling short and long-term risks in power markets: Empirical evidence from Nord Pool

    Nomikos, Nikos K.; Soldatos, Orestes A.

    2010-01-01

    In this paper we propose a three-factor spike model that accounts for different speeds of mean reversion between normal and spiky shocks in the Scandinavian power market. In this model both short and long-run factors are unobservable and are hence estimated as latent variables using the Kalman filter. The proposed model has several advantages. First, it seems to capture in a parsimonious way the most important risks that practitioners face in the market, such as spike risk, short-term risk and long-term risk. Second, it explains the seasonal risk premium observed in the market and improves the fit between theoretical and observed forward prices, particularly for long-dated forward contracts. Finally, closed-form solutions for forward contracts, derived from the model, are consistent with the fact that the correlation between contracts of different maturities is imperfect. The resulting model is very promising, providing a very useful policy analysis and financial engineering tool to market participants for risk management and derivative pricing particularly for long-dated contracts.

  5. Short-Term Wind Power Forecasting Based on Clustering Pre-Calculated CFD Method

    Yimei Wang

    2018-04-01

    Full Text Available To meet the increasing wind power forecasting (WPF demands of newly built wind farms without historical data, physical WPF methods are widely used. The computational fluid dynamics (CFD pre-calculated flow fields (CPFF-based WPF is a promising physical approach, which can balance well the competing demands of computational efficiency and accuracy. To enhance its adaptability for wind farms in complex terrain, a WPF method combining wind turbine clustering with CPFF is first proposed where the wind turbines in the wind farm are clustered and a forecasting is undertaken for each cluster. K-means, hierarchical agglomerative and spectral analysis methods are used to establish the wind turbine clustering models. The Silhouette Coefficient, Calinski-Harabaz index and within-between index are proposed as criteria to evaluate the effectiveness of the established clustering models. Based on different clustering methods and schemes, various clustering databases are built for clustering pre-calculated CFD (CPCC-based short-term WPF. For the wind farm case studied, clustering evaluation criteria show that hierarchical agglomerative clustering has reasonable results, spectral clustering is better and K-means gives the best performance. The WPF results produced by different clustering databases also prove the effectiveness of the three evaluation criteria in turn. The newly developed CPCC model has a much higher WPF accuracy than the CPFF model without using clustering techniques, both on temporal and spatial scales. The research provides supports for both the development and improvement of short-term physical WPF systems.

  6. A review on the young history of the wind power short-term prediction

    Costa, Alexandre; Navarro, Jorge [Wind Energy, Division of Renewable Energies, Department of Energy, CIEMAT, Av. Complutense, 22, Ed. 42, 28044 Madrid (Spain); Crespo, Antonio [Laboratorio de Mecanica de Fluidos, Departmento de Ingenieria Energetica y Fluidomecanica, ETSII, Universidad Politecnica de Madrid, C/Jose Gutierrez Abascal, 2-28006 Madrid (Spain); Lizcano, Gil [Oxford University Centre for the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY (United Kingdom); Madsen, Henrik [Informatics and Mathematical Modelling - IMM, Technical University of Denmark, Richard Petersens Plads, Building 321, Office 019, 2800 Kgs. Lyngby (Denmark); Feitosa, Everaldo [Brazilian Wind Energy Centre - CBEE, Centro de Tecnologia e Geociencias, UFPE-50.740-530 Recife, PE (Brazil)

    2008-08-15

    This paper makes a brief review on 30 years of history of the wind power short-term prediction, since the first ideas and sketches on the theme to the actual state of the art on models and tools, giving emphasis to the most significant proposals and developments. The two principal lines of thought on short-term prediction (mathematical and physical) are indistinctly treated here and comparisons between models and tools are avoided, mainly because, on the one hand, a standard for a measure of performance is still not adopted and, on the other hand, it is very important that the data are exactly the same in order to compare two models (this fact makes it almost impossible to carry out a quantitative comparison between a huge number of models and methods). In place of a quantitative description, a qualitative approach is preferred for this review, remarking the contribution (and innovative aspect) of each model. On the basis of the review, some topics for future research are pointed out. (author)

  7. Series-Tuned High Efficiency RF-Power Amplifiers

    Vidkjær, Jens

    2008-01-01

    An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

  8. Target experiments with high-power proton beams

    Baumung, K; Bluhm, H; Hoppe, P; Rusch, D; Singer, J; Stoltz, O [Forschungszentrum Karlsruhe (Germany); Kanel, G I; Razorenov, S V; Utkin, A V [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Chemical Physics

    1997-12-31

    At the Karlsruhe Light Ion Facility KALE a pulsed high-power proton beam (50 ns, 0.15 TW/cm{sup 2}, 8 mm fwhm focus diameter, 1.7 MeV peak proton energy) is used to generate short, intense pressure pulses or to ablatively accelerate targets 10-100 {mu}m thick to velocities > 10 km/s. The velocity history of the rear target surface is recorded by line-imaging laser Doppler velocimetry with high spatial ({>=} 10 {mu}m) and temporal ({>=} 200 ps) resolution, and provides information on proton beam parameters, and on the state of the matter at high energy densities and intense loading. Utilizing the bell-shaped power density profile the authors demonstrated a new straightforward method for measuring the shock pressure that leads to material melting in the rarefaction wave. For the first time, the dynamic tensile strength was measured across a crystal grain boundary, and using targets with a 1D periodic structure, the growth rate of a Rayleigh Taylor instability could be measured for the first time in direct drive experiments with an ion beam. (author). 8 figs., 15 refs.

  9. Splitting of high power, cw proton beams

    Alberto Facco

    2007-09-01

    Full Text Available A simple method for splitting a high power, continuous wave (cw proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility design study. The aim of the system is to deliver up to 4 MW of H^{-} beam to the main radioactive ion beam production target, and up to 100 kW of proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fraction of the main H^{-} beam, magnetic splitting of H^{-} and H^{0}, and stripping of H^{0} to H^{+}. The method allows slow raising and individual fine adjustment of the beam intensity in each branch.

  10. Survey on modern pulsed high power lasers

    Witte, K.J.

    1985-01-01

    The requirements to be met by lasers for particle acceleration are partially similar to those already known for fusion lasers. The power level wanted in both caes is up to 100 TW or even more. The pulse durations favourable for laser accelerators are in the range from 1 ps to 1000 ps whereas fusion lasers require several ns. The energy range for laser accelerators is thus correspondingly smaller than that for fusion lasers: 1-100 kJ versus several 100 kJ. The design criteria of lasers meeting the requirements are discussed in the following. The CO 2 , iodine, Nd:glass and excimer lasers are treated in detail. The high repetition rate aspect will not be particularly addressed since for the present generation of lasers the wanted rates of far above 1 Hz are completely out of scope. Moreover, for the demonstration of principle these rates are not needed. (orig./HSI)

  11. QED studies using high-power lasers

    Mattias Marklund

    2010-01-01

    Complete text of publication follows. The event of extreme lasers, which intensities above 10 22 W/cm 2 will be reached on a routine basis, will give us opportunities to probe new aspects of quantum electrodynamics. In particular, the non-trivial properties of the quantum vacuum can be investigated as we reach previously unattainable laser intensities. Effects such as vacuum birefringence and pair production in strong fields could thus be probed. The prospects of obtaining new insights regarding the non-perturbative structure of quantum field theories shows that the next generation laser facilities can be important tool for fundamental physical studies. Here we aim at giving a brief overview of such aspects of high-power laser physics.

  12. High-power laser diodes with high polarization purity

    Rosenkrantz, Etai; Yanson, Dan; Peleg, Ophir; Blonder, Moshe; Rappaport, Noam; Klumel, Genady

    2017-02-01

    Fiber-coupled laser diode modules employ power scaling of single emitters for fiber laser pumping. To this end, techniques such as geometrical, spectral and polarization beam combining (PBC) are used. For PBC, linear polarization with high degree of purity is important, as any non-perfectly polarized light leads to losses and heating. Furthermore, PBC is typically performed in a collimated portion of the beams, which also cancels the angular dependence of the PBC element, e.g., beam-splitter. However, we discovered that single emitters have variable degrees of polarization, which depends both on the operating current and far-field divergence. We present data to show angle-resolved polarization measurements that correlate with the ignition of high-order modes in the slow-axis emission of the emitter. We demonstrate that the ultimate laser brightness includes not only the standard parameters such as power, emitting area and beam divergence, but also the degree of polarization (DoP), which is a strong function of the latter. Improved slow-axis divergence, therefore, contributes not only to high brightness but also high beam combining efficiency through polarization.

  13. High technology supporting nuclear power industry in CRIEPI

    Ueda, Nobuyuki

    2009-01-01

    As a central research institute of electric power industry, Central Research Institute of Electric Power Industry (CRIEPI) has carried out R and D on broad range of topics such as power generation, power transmission, power distribution, power application and energy economics and society, aiming to develop prospective and advanced technologies, fundamental reinforce technologies and next-generation core technologies. To realize low-carbon society to cope with enhancement of global environmental issues, nuclear power is highly recommended as large-scale power with low-carbon emission. At the new start of serial explanation on advanced technologies, R and D on electric power industry was outlined. (T. Tanaka)

  14. Switching transients in high-frequency high-power converters using power MOSFET's

    Sloane, T. H.; Owen, H. A., Jr.; Wilson, T. G.

    1979-01-01

    The use of MOSFETs in a high-frequency high-power dc-to-dc converter is investigated. Consideration is given to the phenomena associated with the paralleling of MOSFETs and to the effect of stray circuit inductances on the converter circuit performance. Analytical relationships between various time constants during the turning-on and turning-off intervals are derived which provide estimates of plateau and peak levels during these intervals.

  15. Wind Power Forecasting Based on Echo State Networks and Long Short-Term Memory

    Erick López

    2018-02-01

    Full Text Available Wind power generation has presented an important development around the world. However, its integration into electrical systems presents numerous challenges due to the variable nature of the wind. Therefore, to maintain an economical and reliable electricity supply, it is necessary to accurately predict wind generation. The Wind Power Prediction Tool (WPPT has been proposed to solve this task using the power curve associated with a wind farm. Recurrent Neural Networks (RNNs model complex non-linear relationships without requiring explicit mathematical expressions that relate the variables involved. In particular, two types of RNN, Long Short-Term Memory (LSTM and Echo State Network (ESN, have shown good results in time series forecasting. In this work, we present an LSTM+ESN architecture that combines the characteristics of both networks. An architecture similar to an ESN is proposed, but using LSTM blocks as units in the hidden layer. The training process of this network has two key stages: (i the hidden layer is trained with a descending gradient method online using one epoch; (ii the output layer is adjusted with a regularized regression. In particular, the case is proposed where Step (i is used as a target for the input signal, in order to extract characteristics automatically as the autoencoder approach; and in the second stage (ii, a quantile regression is used in order to obtain a robust estimate of the expected target. The experimental results show that LSTM+ESN using the autoencoder and quantile regression outperforms the WPPT model in all global metrics used.

  16. Chaos in high-power high-frequency gyrotrons

    Airila, M.

    2004-01-01

    Gyrotron interaction is a complex nonlinear dynamical process, which may turn chaotic in certain circumstances. The emergence of chaos renders dynamical systems unpredictable and causes bandwidth broadening of signals. Such effects would jeopardize the prospect of advanced gyrotrons in fusion. Therefore, it is important to be aware of the possibility of chaos in gyrotrons. There are three different chaos scenarios closely related to the development of high-power gyrotrons: First, the onset of chaos in electron trajectories would lead to difficulties in the design and efficient operation of depressed potential collectors, which are used for efficiency enhancement. Second, the radio-frequency signal could turn chaotic, decreasing the output power and the spectral purity of the output signal. As a result, mode conversion, transmission, and absorption efficiencies would be reduced. Third, spatio-temporal chaos in the resonator field structure can set a limit for the use of large-diameter interaction cavities and high-order TE modes (large azimuthal index) allowing higher generated power. In this thesis, the issues above are addressed with numerical modeling. It is found that chaos in electron residual energies is practically absent in the parameter region corresponding to high efficiency. Accordingly, depressed collectors are a feasible solution also in advanced high-power gyrotrons. A new method is presented for straightforward numerical solution of the one-dimensional self-consistent time-dependent gyrotron equations, and the method is generalized to two dimensions. In 1D, a chart of gyrotron oscillations is calculated. It is shown that the regions of stationary oscillations, automodulation, and chaos have a complicated topology in the plane of generalized gyrotron variables. The threshold current for chaotic oscillations exceeds typical operating currents by a factor of ten. However, reflection of the output signal may significantly lower the threshold. 2D

  17. Power transistor module for high current applications

    Cilyo, F.F.

    1975-01-01

    One of the parts needed for the control system of the 400-GeV accelerator at Fermilab was a power transistor with a safe operating area of 1800A at 50V, dc current gain of 100,000 and 20 kHz bandwidth. Since the commercially available discrete devices and power hybrid packages did not meet these requirements, a power transistor module was developed which performed satisfactorily. By connecting 13 power transistors in parallel, with due consideration for network and heat dissipation problems, and by driving these 13 with another power transistor, a super power transistor is made, having an equivalent current, power, and safe operating area capability of 13 transistors. For higher capabilities, additional modules can be conveniently added. (auth)

  18. High power accelerator for environmental application

    Han, B.; Kim, J.K.; Kim, Y.R.; Kim, S.M.

    2011-01-01

    The problems of environmental damage and degradation of natural resources are receiving increasing attention throughout the world. The increased population, higher living standards, increased urbanization and enhanced industrial activities of humankind are all leading to degradation of the environment. Increasing urbanization has been accompanied by significant environmental pollution, given the seriousness of the situation and future risk of crises, there is an urgent need to develop the efficient technologies including economical treatment methods. Therefore, cost-effective treatment of the stack gases, wastewater and sludge containing refractory pollutant with electron beam is actively studied in EB TECH Co. Electron beam treatment of such hazardous wastes is caused by the decomposition of pollutants as a result of their reactions with highly reactive species formed from radiolysis. However, to have advantages over existing processes, the electron beam process should have cost-effective and reliable in operation. Therefore high power accelerators (400kW~1MW) are developed for environmental application and they show the decrease in the cost of construction and operation of electron beam plant. In other way to reduce the cost for treatment, radical reactions accompanied by the other processes are introduced, and the synergistic effect upon the use of combined methods such as electron beam treatment with catalytic system, biological treatment and physico-chemical adsorption and others also show the improvement of the effect of electron beam treatment. (author)

  19. High-average-power solid state lasers

    Summers, M.A.

    1989-01-01

    In 1987, a broad-based, aggressive R ampersand D program aimed at developing the technologies necessary to make possible the use of solid state lasers that are capable of delivering medium- to high-average power in new and demanding applications. Efforts were focused along the following major lines: development of laser and nonlinear optical materials, and of coatings for parasitic suppression and evanescent wave control; development of computational design tools; verification of computational models on thoroughly instrumented test beds; and applications of selected aspects of this technology to specific missions. In the laser materials areas, efforts were directed towards producing strong, low-loss laser glasses and large, high quality garnet crystals. The crystal program consisted of computational and experimental efforts aimed at understanding the physics, thermodynamics, and chemistry of large garnet crystal growth. The laser experimental efforts were directed at understanding thermally induced wave front aberrations in zig-zag slabs, understanding fluid mechanics, heat transfer, and optical interactions in gas-cooled slabs, and conducting critical test-bed experiments with various electro-optic switch geometries. 113 refs., 99 figs., 18 tabs

  20. High power accelerator for environmental application

    Han, B.; Kim, J. K.; Kim, Y. R.; Kim, S. M. [EB-TECH Co., Ltd., Yuseong-gu Daejeon (Korea, Republic of)

    2011-07-01

    The problems of environmental damage and degradation of natural resources are receiving increasing attention throughout the world. The increased population, higher living standards, increased urbanization and enhanced industrial activities of humankind are all leading to degradation of the environment. Increasing urbanization has been accompanied by significant environmental pollution, given the seriousness of the situation and future risk of crises, there is an urgent need to develop the efficient technologies including economical treatment methods. Therefore, cost-effective treatment of the stack gases, wastewater and sludge containing refractory pollutant with electron beam is actively studied in EB TECH Co. Electron beam treatment of such hazardous wastes is caused by the decomposition of pollutants as a result of their reactions with highly reactive species formed from radiolysis. However, to have advantages over existing processes, the electron beam process should have cost-effective and reliable in operation. Therefore high power accelerators (400kW~1MW) are developed for environmental application and they show the decrease in the cost of construction and operation of electron beam plant. In other way to reduce the cost for treatment, radical reactions accompanied by the other processes are introduced, and the synergistic effect upon the use of combined methods such as electron beam treatment with catalytic system, biological treatment and physico-chemical adsorption and others also show the improvement of the effect of electron beam treatment. (author)

  1. High power accelerators and wastewater treatment

    Han, B.; Kim, J.K.; Kim, Y.R.; Kim, S.M.; Makaov, I.E.; Ponomarev, A.V.

    2006-01-01

    The problems of environmental damage and degradation of natural resources are receiving increasing attention throughout the world. The increased population, higher living standards, increased urbanization and enhanced industrial activities of humankind are all leading to degradation of the environment. Increasing urbanization has been accompanied by significant water pollution. Given the seriousness of the situation and future risk of crises, there is an urgent need to develop the water-efficient technologies including economical treatment methods of wastewater and polluted water. Therefore, cost-effective treatment of the municipal and industrial wastewater containing refractory pollutant with electron beam is actively studied in EB TECH Co.. Electron beam treatment of wastewater is caused by the decomposition of pollutants as a result of their reactions with highly reactive species formed from water radiolysis (hydrated electron, OH free radical and H atom). However, to have advantages over existing processes, the electron beam process should have cost-effective and reliable in operation. Therefore high power accelerators (400kW∼1MW) are developed for environmental application and they show the decrease in the cost of construction and operation of electron beam plant. In other way to reduce the cost for wastewater treatment, radical reactions accompanied by the other processes are introduced, and the synergistic effect upon the use of combined methods such as electron beam treatment with ozonation, biological treatment and physico-chemical adsorption and others also show the improvement of the effect of electron beam treatment for the wastewater purification. (author)

  2. High power diode lasers converted to the visible

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Andersen, Peter E.

    2017-01-01

    High power diode lasers have in recent years become available in many wavelength regions. However, some spectral regions are not well covered. In particular, the visible spectral range is lacking high power diode lasers with good spatial quality. In this paper, we highlight some of our recent...... results in nonlinear frequency conversion of high power near infrared diode lasers to the visible spectral region....

  3. High RF Power Production for CLIC

    Syratchev, I; Adli, E; Taborelli, M

    2007-01-01

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and excite preferentially the synchronous mode. The RF power produced (several hundred MW) is collected at the downstream end of the structure by means of the Power Extractor and delivered to the main linac structure. The PETS geometry is a result of multiple compromises between beam stability and main linac RF power needs. Another requirement is to provide local RF power termination in case of accelerating structure failure (ON/OFF capability). Surface electric and magnetic fields, power extraction method, HOM damping, ON/OFF capability and fabrication technology were all evaluated to provide a reliable design

  4. PASTEURISASI HIGH TEMPERATURE SHORT TIME (HTST) SUSU TERHADAP Listeria monocytogenes PADA PENYIMPANAN REFRIGERATOR

    SABIL, SYAHRIANA

    2015-01-01

    2015 SYAHRIANA SABIL (I 111 11 273). Pasteurisasi High Temperature Short Time (HTST) Susu terhadap Listeria monocytogenes pada Penyimpanan Refrigerator. Dibimbing oleh RATMAWATI MALAKA dan FARIDA NUR YULIATI. Pasteurisasi High Temperature Short Time (HTST) merupakan proses pemanasan susu di bawah titik didih yang diharapkan dapat membunuh Listeria monocytogenes (L. monocytogenes) karena bersifat patogen dan mengakibatkan listeriosis yang merupakan penyakit zoonosis. Tu...

  5. Tomographic Particle Image Velocimetry using Pulsed, High Power LED Volume Illumination

    Buchmann, N. A.; Willert, C.; Soria, J.

    2011-01-01

    This paper investigates the use of high-power light emitting diode (LED) illumination in Particle Image Velocimetry (PIV) as an alternative to traditional laser-based illumination. The solid-state LED devices can provide averaged radiant power in excess of 10W and by operating the LEDs with short current pulses, considerably higher than in continuous operation, light pulses of sufficient energy suitable for imaging micron-sized particles can be generated. The feasibility of this LED-based ill...

  6. The SPES High Power ISOL production target

    Andrighetto, A.; Corradetti, S.; Ballan, M.; Borgna, F.; Manzolaro, M.; Scarpa, D.; Monetti, A.; Rossignoli, M.; Silingardi, R.; Mozzi, A.; Vivian, G.; Boratto, E.; De Ruvo, L.; Sattin, N.; Meneghetti, G.; Oboe, R.; Guerzoni, M.; Margotti, A.; Ferrari, M.; Zenoni, A.; Prete, G.

    2016-11-01

    SPES (Selective Production of Exotic Species) is a facility under construction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams (RIBs). These will be obtained using the ISOL (Isotope Separation On-Line) method, bombarding a uranium carbide target with a proton beam of 40MeV energy and currents up to 200μA. The target configuration was designed to obtain a high number of fissions, up to 1013 per second, low power deposition and fast release of the produced isotopes. The exotic isotopes generated in the target are ionized, mass separated and re-accelerated by the ALPI superconducting LINAC at energies of 10AMeV and higher, for masses in the region of A = 130 amu , with an expected rate on the secondary target up to 109 particles per second. In this work, recent results on the R&D activities regarding the SPES RIB production target-ion source system are reported.

  7. High-power pure blue laser diodes

    Ohta, M.; Ohizumi, Y.; Hoshina, Y.; Tanaka, T.; Yabuki, Y.; Goto, S.; Ikeda, M. [Development Center, Sony Shiroishi Semiconductor Inc., Miyagi (Japan); Funato, K. [Materials Laboratories, Sony Corporation, Kanagawa (Japan); Tomiya, S. [Materials Analysis Laboratory, Sony Corporation, Kanagawa (Japan)

    2007-06-15

    We successfully developed high-power and long-lived pure blue laser diodes (LDs) having an emission wavelength of 440-450 nm. The pure-blue LDs were grown by metalorganic chemical vapor deposition (MOCVD) on GaN substrates. The dislocation density was successfully reduced to {proportional_to}10{sup 6} cm{sup -2} by optimizing the MOCVD growth conditions and the active layer structure. The vertical layer structure was designed to have an absorption loss of 4.9 cm{sup -1} and an internal quantum efficiency of 91%. We also reduced the operating current density to 6 kA/cm{sup 2} under 750 mW continuous-wave operation at 35 C by optimizing the stripe width to 12 {mu}m and the cavity length to 2000 {mu}m. The half lifetimes in constant current mode are estimated to be longer than 10000 h. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Complete low power controller for high voltage power systems

    Sumner, R.; Blanar, G.

    1997-01-01

    The MHV100 is a custom CMOS integrated circuit, developed for the AMS experiment. It provides complete control for a single channel high voltage (HV) generator and integrates all the required digital communications, D to A and A to D converters, the analog feedback loop and output drivers. This chip has been designed for use in both distributed high voltage systems or for low cost single channel high voltage systems. The output voltage and current range is determined by the external components

  9. High-Altitude Wind Power Generation

    Fagiano, L.; Milanese, M.; Piga, D.

    2010-01-01

    Abstract—The paper presents the innovative technology of highaltitude wind power generation, indicated as Kitenergy, which exploits the automatic flight of tethered airfoils (e.g., power kites) to extract energy from wind blowing between 200 and 800 m above the ground. The key points of this

  10. 30 GHz High Power Production for CLIC

    Syratchev, I V

    2006-01-01

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and excite preferentially the synchronous TM01 mode at 30 GHz. The RF power produced (several hundred MW) is collected at the downstream end of the structure by means of the Power Extractor and conveyed to the main linac structure. The PETS geometry is a result of multiple compromises between beam stability along a single decelerator sector (600 m) and the active length of the structure to match the main linac RF power needs and layout. Surface electric and magnetic fields, power extraction method, HOM damping, ON/OFF capability and fabrication technology were all evaluated to provide a reliable design.

  11. A short-term ensemble wind speed forecasting system for wind power applications

    Baidya Roy, S.; Traiteur, J. J.; Callicutt, D.; Smith, M.

    2011-12-01

    This study develops an adaptive, blended forecasting system to provide accurate wind speed forecasts 1 hour ahead of time for wind power applications. The system consists of an ensemble of 21 forecasts with different configurations of the Weather Research and Forecasting Single Column Model (WRFSCM) and a persistence model. The ensemble is calibrated against observations for a 2 month period (June-July, 2008) at a potential wind farm site in Illinois using the Bayesian Model Averaging (BMA) technique. The forecasting system is evaluated against observations for August 2008 at the same site. The calibrated ensemble forecasts significantly outperform the forecasts from the uncalibrated ensemble while significantly reducing forecast uncertainty under all environmental stability conditions. The system also generates significantly better forecasts than persistence, autoregressive (AR) and autoregressive moving average (ARMA) models during the morning transition and the diurnal convective regimes. This forecasting system is computationally more efficient than traditional numerical weather prediction models and can generate a calibrated forecast, including model runs and calibration, in approximately 1 minute. Currently, hour-ahead wind speed forecasts are almost exclusively produced using statistical models. However, numerical models have several distinct advantages over statistical models including the potential to provide turbulence forecasts. Hence, there is an urgent need to explore the role of numerical models in short-term wind speed forecasting. This work is a step in that direction and is likely to trigger a debate within the wind speed forecasting community.

  12. A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

    Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2018-01-01

    . This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage upto 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wideband gap semiconductor devices of GaN switches and SiC diodes are combined...... to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated halfbridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved......State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable...

  13. A high-power rf linear accelerator for FELS [free-electron lasers

    Sheffield, R.L.; Watson, J.M.

    1987-01-01

    This paper describes the design of a high average current rf linear accelerator suitable for driving short-wavelength free-electron lasers (FEL). It is concluded that the design of a room-temperature rf linear acelerator that can meet the stringent requirements of a high-power short-wavelength FEL appears possible. The accelerator requires the use of an advanced photoelectric injector that is under development; the accelerator components, however, do not require appreciable development. At these large beam currents, low-frequency, large-bore room-temperature cavities can be highly efficient and give all specified performance with minimal risk. 20 refs

  14. Measurement of high-power microwave pulse under intense ...

    Abstract. KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator. (VIRCATOR) device. HPM power measurements were carried out using a transmitting– receiving system in the presence of intense high frequency (a few ...

  15. On the origin of very-high-energy photons in astrophysics: a short introduction to acceleration and radiation physics

    Lemoine, M.; Pelletier, G.

    2015-01-01

    Powerful astrophysical sources produce non-thermal spectra of very-high-energy photons, with generic power-law distributions, through various radiative processes of charged particles, e.g., synchrotron radiation, inverse Compton processes, and hadronic interactions. Those charged particles have themselves been accelerated to ultra-relativistic energies in intense electromagnetic fields in the source. In many cases, the exact acceleration scheme is not known, but standard scenarios, such as Fermi mechanisms and reconnection processes are generally considered as prime suspects for the conversion of bulk kinetic or electromagnetic energy into a power law of supra-thermal particles. This paper proposes a short introduction to the various acceleration and radiative processes which shape the distributions of very-high-energy photons (E > 100 MeV) in astrophysics. (authors)

  16. Study and development of 22 kW peak power fiber coupled short pulse Nd:YAG laser for cleaning applications

    Choubey, Ambar; Vishwakarma, S. C.; Vachhani, D. M.; Singh, Ravindra; Misra, Pushkar; Jain, R. K.; Arya, R.; Upadhyaya, B. N.; Oak, S. M.

    2014-11-01

    Free running short pulse Nd:YAG laser of microsecond pulse duration and high peak power has a unique capability to ablate material from the surface without heat propagation into the bulk. Applications of short pulse Nd:YAG lasers include cleaning and restoration of marble, stones, and a variety of metals for conservation. A study on the development of high peak power short pulses from Nd:YAG laser along with its cleaning and conservation applications has been performed. A pulse energy of 1.25 J with 55 μs pulse duration and a maximum peak power of 22 kW has been achieved. Laser beam has an M2 value of ~28 and a pulse-to-pulse stability of ±2.5%. A lower value of M2 means a better beam quality of the laser in multimode operation. A top hat spatial profile of the laser beam was achieved at the exit end of 200 μm core diameter optical fiber, which is desirable for uniform cleaning. This laser system has been evaluated for efficient cleaning of surface contaminations on marble, zircaloy, and inconel materials for conservation with cleaning efficiency as high as 98%. Laser's cleaning quality and efficiency have been analysed by using a microscope, a scanning electron microscope (SEM), and X-ray photon spectroscopy (XPS) measurements.

  17. High quality, high efficiency welding technology for nuclear power plants

    Aoki, Shigeyuki; Nagura, Yasumi

    1996-01-01

    For nuclear power plants, it is required to ensure the safety under the high reliability and to attain the high rate of operation. In the manufacture and installation of the machinery and equipment, the welding techniques which become the basis exert large influence to them. For the purpose of improving joint performance and excluding human errors, welding heat input and the number of passes have been reduced, the automation of welding has been advanced, and at present, narrow gap arc welding and high energy density welding such as electron beam welding and laser welding have been put to practical use. Also in the welding of pipings, automatic gas metal arc welding is employed. As for the welding of main machinery and equipment, there are the welding of the joints that constitute pressure boundaries, the build-up welding on the internal surfaces of pressure vessels for separating primary water from them, and the sealing welding of heating tubes and tube plates in steam generators. These weldings are explained. The welding of pipings and the state of development and application of new welding methods are reported. (K.I.)

  18. High performance magnet power supply optimization

    Jackson, L.T.

    1975-01-01

    Three types of magnet power supply systems for the joint LBL-SLAC proposed accelerator PEP are discussed. The systems considered include a firing circuit and six-pulse controlled rectifier, transistor systems, and a chopper system. (U.S.)

  19. Controlled Compact High Voltage Power Lines

    Postolati V.

    2016-04-01

    Full Text Available Nowadays modern overhead transmission lines (OHL constructions having several significant differences from conventional ones are being used in power grids more and more widely. Implementation of compact overhead lines equipped with FACTS devices, including phase angle regulator settings (compact controlled OHL, appears to be one of the most effective ways of power grid development. Compact controlled AC HV OHL represent a new generation of power transmission lines embodying recent advanced achievements in design solutions, including towers and insulation, together with interconnection schemes and control systems. Results of comprehensive research and development in relation to 110–500kV compact controlled power transmission lines together with theoretical basis, substantiation, and methodological approaches to their practical application are presented in the present paper.

  20. Advanced Capacitors for High-Power Applications, Phase I

    National Aeronautics and Space Administration — As the consumer and industrial requirements for compact, high-power-density, electrical power systems grow substantially over the next decade; there will be a...

  1. Advances in high-power rf amplifiers

    Tallerico, P.J.

    1979-01-01

    Several powerful accelerators and storage rings are being considered that will require tens or even hundreds of megawatts of continuous rf power. The economics of such large machines can be dictated by the cost and efficiency of the rf amplifiers. The overall design and performance of such narrow-band amplifiers, operating in the 50- to 1500-MHz region, are being theoretically studied as a function of frequency to determine the optimum rf amplifier output power, gain, efficiency, and dc power requirements. The state of the art for three types of amplifiers (gridded tubes, klystrons, and gyrocons) is considered and the development work necessary to improve each is discussed. The gyrocon is a new device, hence its various embodiments are discussed in detail. The Soviet designs are reviewed and the gyrocon's strengths and weaknesses are compared to other types of microwave amplifiers. The primary advantages of the gyrocon are the very large amount of power available from a single device and the excellent efficiency and stable operation. The klystron however, has much greater gain and is simpler mechanically. At very low frequencies, the small size of the gridded tube makes it the optimum choice for all but the most powerful systems

  2. Design and development of high voltage high power operational ...

    Applications of power operational amplifiers (opamps) are increasing day by day in the industry as they are used in audio amplifiers, Piezo transducer systems and the electron deflection systems. Power operational amplifiers have all the features of a general purpose opamp except the additional power handling capability.

  3. Atmospheric Propagation and Combining of High-Power Lasers

    2015-09-08

    Brightness-scaling potential of actively phase- locked solid state laser arrays,” IEEE J. Sel. Topics Quantum Electron., vol. 13, no. 3, pp. 460–472, May...attempting to phase- lock high-power lasers, which is not encountered when phase- locking low-power lasers, for example mW power levels. Regardless, we...technology does not currently exist. This presents a challenging problem when attempting to phase- lock high-power lasers, which is not encountered when

  4. Welding with high power fiber lasers - A preliminary study

    Quintino, L.; Costa, A.; Miranda, R.; Yapp, D.; Kumar, V.; Kong, C.J.

    2007-01-01

    The new generation of high power fiber lasers presents several benefits for industrial purposes, namely high power with low beam divergence, flexible beam delivery, low maintenance costs, high efficiency and compact size. This paper presents a brief review of the development of high power lasers, and presents initial data on welding of API 5L: X100 pipeline steel with an 8 kW fiber laser. Weld bead geometry was evaluated and transition between conduction and deep penetration welding modes was investigated

  5. The state-of-the-art in short-term prediction of wind power. A literature overview

    Giebel, G.; Brownsword, R.; Kariniotakis, G.

    2003-08-01

    Based on an appropriate questionnaire (WP1.1) and some other works already in progress, this report details the state-of-the-art in short term prediction of wind power, mostly summarising nearly all existing literature on the topic. (au)

  6. Modular High Voltage Pulse Converter for Short Rise and Decay Times

    Mao, S.

    2018-01-01

    This thesis explores a modular HV pulse converter technology with short rise and decay times. A systematic methodology to derive and classify HV architectures based on a modularization level of power building blocks of the HV pulse converter is developed to summarize existing architectures and

  7. A fast network solution by the decoupled procedure during short-term dynamic processes in power systems

    Popovic, D P; Stefanovic, M D [Nikola Tesla Inst., Belgrade (YU). Power System Dept.

    1990-01-01

    A simple, fast and reliable decoupled procedure for solving the network problems during short-term dynamic processes in power systems is presented. It is based on the Newton-Raphson method applied to the power balance equations, which include the effects of generator saliency and non-impedance loads, with further modifications resulting from the physical properties of the phenomena under study. The good convergence characteristics of the developed procedure are demonstrated, and a comparison is made with the traditional method based on the current equation and the triangularized admittance matrix, using the example of stability analysis of the Yugoslav power grid. (author).

  8. Comparison of axial length, anterior chamber depth and intraocular lens power between IOLMaster and ultrasound in normal, long and short eyes.

    Dong, Jing; Zhang, Yaqin; Zhang, Haining; Jia, Zhijie; Zhang, Suhua; Wang, Xiaogang

    2018-01-01

    To compare the axial length (AL), anterior chamber depth (ACD) and intraocular lens power (IOLP) of IOLMaster and Ultrasound in normal, long and short eyes. Seventy-four normal eyes (≥ 22 mm and ≤ 25 mm), 74 long eyes (> 25 mm) and 78 short eyes (devices in the order of IOLMaster followed by Ultrasound. The IOLP were calculated using a free online LADAS IOL formula calculator. The difference in AL and IOLP between IOLMaster and Ultrasound was statistically significant when all three groups were combined. The difference in ACD between IOLMaster and Ultrasound was statistically significant in the normal group (Peye group (Peye group (P = 0.465). For the IOLP difference between IOLMaster and Ultrasound in the normal group, the percentage of IOLP differences eye group, they were 90.5%, 5.4%, 4.1% and 0%, respectively. For the short eye group, they were 61.5%, 23.1%, 10.3%, and 5.1%, respectively. IOLMaster and Ultrasound have statistically significant differences in AL measurements and IOLP (using LADAS formula) for normal, long eye and short eye. The two instruments agree regarding ACD measurements for the long eye group, but differ for the normal and short eye groups. Moreover, the high percentage of IOLP differences greater than |0.5|D in the short eye group is noteworthy.

  9. Novel short-pulse laser diode source for high-resolution 3D flash lidar

    Canal, Celine; Laugustin, Arnaud; Kohl, Andreas; Rabot, Olivier

    2017-06-01

    Imaging based on laser illumination is present in various fields of applications such as medicine, security, defense, civil engineering and in the automotive sector. In this last domain, research and development to bring autonomous vehicles on the roads has been intensified the recent years. Among the various technologies currently studied, automotive lidars are a fast-growing one due to their accuracy to detect a wide range of objects at distances up to a few hundreds of meters in various weather conditions. First commercialized devices for ADAS were laser scanners. Since then, new architectures have recently appeared such as solid-state lidar and flash lidar that offer a higher compactness, robustness and a cost reduction. Flash lidars are based on time-of-flight measurements, with the particularity that they do not require beam scanners because only one short laser pulse with a large divergence is used to enlighten the whole scene. Depth of encountered objects can then be recovered from measurement of echoed light at once, hence enabling real-time 3D mapping of the environment. This paper will bring into the picture a cutting edge laser diode source that can deliver millijoule pulses as short as 12 ns, which makes them highly suitable for integration in flash lidars. They provide a 100-kW peak power highly divergent beam in a footprint of 4x5 cm2 (including both the laser diode and driver) and with a 30-% electrical-to-optical efficiency, making them suitable for integration in environments in which compactness and power consumption are a priority. Their emission in the range of 800-1000 nm is considered to be eye safe when taking into account the high divergence of the output beam. An overview of architecture of these state-of-the-art pulsed laser diode sources will be given together with some solutions for their integration in 3D mapping systems. Future work leads will be discussed for miniaturization of the laser diode and drastic cost reduction.

  10. High power diode pumped solid state lasers

    Solarz, R.; Albrecht, G.; Beach, R.; Comaskey, B.

    1992-01-01

    Although operational for over twenty years, diode pumped solid state lasers have, for most of their existence, been limited to individual diodes pumping a tiny volume of active medium in an end pumped configuration. More recent years have witnessed the appearance of diode bars, packing around 100 diodes in a 1 cm bar which have enabled end and side pumped small solid state lasers at the few Watt level of output. This paper describes the subsequent development of how proper cooling and stacking of bars enables the fabrication of multi kill average power diode pump arrays with irradiances of 1 kw/cm peak and 250 W/cm 2 average pump power. Since typical conversion efficiencies from the diode light to the pumped laser output light are of order 30% or more, kW average power diode pumped solid state lasers now are possible

  11. Regime dependence of photo-darkening-induced modal degradation in high power fiber amplifier (Conference Presentation)

    Boullet, Johan; Vincont, Cyril; Jolly, Alain; Pierre, Christophe

    2017-03-01

    Thermally induced transverse modal instabilities (TMI) have attracted these five years an intense research efforts of the entire fiber laser development community, as it represents the current most limiting effect of further power scaling of high power fiber laser. Anyway, since 2014, a few publications point out a new limiting thermal effect: fiber modal degradation (FMD). It is characterized by a power rollover and simultaneous increase of the cladding light at an average power far from the TMI threshold together with a degraded beam which does not exhibit temporal fluctuations, which is one of the main characteristic of TMI. We report here on the first systemic experimental study of FMD in a high power photonic crystal fiber. We put a particular emphasis on the dependence of its average power threshold on the regime of operation. We experimentally demonstrate that this dependence is intrinsically linked to regime-dependent PD-saturated losses, which are nearly three times higher in CW regime than in short pulse picosecond regime. We make the hypothesis that the existence of these different PD equilibrium states between CW regime and picosecond QCW pulsed regime is due to a partial photo-bleaching of color centers in picosecond regime thanks to a higher probability of multi-photon process induced photobleaching (PB) at high peak power. This hypothesis is corroborated by the demonstration of the reversibility of the FMD induced in CW regime by simply switching the seed CW 1064 nm light by a short pulse, picosecond oscillator.

  12. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1996-01-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several μs) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  13. High ion charge states in a high-current, short-pulse, vacuum arc ion source

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1995-09-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1--4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several micros) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  14. Implications of Wide-Area Geographic Diversity for Short- Term Variability of Solar Power

    Mills, Andrew; Wiser, Ryan

    2010-08-23

    Worldwide interest in the deployment of photovoltaic generation (PV) is rapidly increasing. Operating experience with large PV plants, however, demonstrates that large, rapid changes in the output of PV plants are possible. Early studies of PV grid impacts suggested that short-term variability could be a potential limiting factor in deploying PV. Many of these early studies, however, lacked high-quality data from multiple sites to assess the costs and impacts of increasing PV penetration. As is well known for wind, accounting for the potential for geographic diversity can significantly reduce the magnitude of extreme changes in aggregated PV output, the resources required to accommodate that variability, and the potential costs of managing variability. We use measured 1-min solar insolation for 23 time-synchronized sites in the Southern Great Plains network of the Atmospheric Radiation Measurement program and wind speed data from 10 sites in the same network to characterize the variability of PV with different degrees of geographic diversity and to compare the variability of PV to the variability of similarly sited wind. The relative aggregate variability of PV plants sited in a dense 10 x 10 array with 20 km spacing is six times less than the variability of a single site for variability on time scales less than 15-min. We find in our analysis of wind and PV plants similarly sited in a 5 x 5 grid with 50 km spacing that the variability of PV is only slightly more than the variability of wind on time scales of 5-15 min. Over shorter and longer time scales the level of variability is nearly identical. Finally, we use a simple approximation method to estimate the cost of carrying additional reserves to manage sub-hourly variability. We conclude that the costs of managing the short-term variability of PV are dramatically reduced by geographic diversity and are not substantially different from the costs for managing the short-term variability of similarly sited wind in

  15. Small-bandgap polymer solar cells with unprecedented short-circuit current density and high fill factor.

    Choi, Hyosung; Ko, Seo-Jin; Kim, Taehyo; Morin, Pierre-Olivier; Walker, Bright; Lee, Byoung Hoon; Leclerc, Mario; Kim, Jin Young; Heeger, Alan J

    2015-06-03

    Small-bandgap polymer solar cells (PSCs) with a thick bulk heterojunction film of 340 nm exhibit high power conversion efficiencies of 9.40% resulting from high short-circuit current density (JSC ) of 20.07 mA cm(-2) and fill factor of 0.70. This remarkable efficiency is attributed to maximized light absorption by the thick active layer and minimized recombination by the optimized lateral and vertical morphology through the processing additive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Solid-state high voltage modulator and its application to rf source high voltage power supplies

    Tooker, J.F.; Huynh, P.; Street, R.W.

    2009-01-01

    A solid-state high voltage modulator is described in which series-connected insulated-gate bipolar transistors (IGBTs) are switched at a fixed frequency by a pulse width modulation (PWM) regulator, that adjusts the pulse width to control the voltage out of an inductor-capacitor filter network. General Atomics proposed the HV power supply (HVPS) topology of multiple IGBT modulators connected to a common HVdc source for the large number of 1 MW klystrons in the linear accelerator of the Accelerator Production of Tritium project. The switching of 24 IGBTs to obtain 20 kVdc at 20 A for short pulses was successfully demonstrated. This effort was incorporated into the design of a -70 kV, 80 A, IGBT modulator, and in a short-pulse test 12 IGBTs regulated -5 kV at 50 A under PWM control. These two tests confirm the practicality of solid-state IGBT modulators to regulate high voltage at reasonable currents. Tokamaks such as ITER require large rf heating and current drive systems with multiple rf sources. A HVPS topology is presented that readily adapts to the three rf heating systems on ITER. To take advantage of the known economy of scale for power conversion equipment, a single HVdc source feeds multiple rf sources. The large power conversion equipment, which is located outside, converts the incoming utility line voltage directly to the HVdc needed for the class of rf sources connected to it, to further reduce cost. The HVdc feeds a set of IGBT modulators, one for each rf source, to independently control the voltage applied to each source, maximizing operational flexibility. Only the modulators are indoors, close to the rf sources, minimizing the use of costly near-tokamak floor space.

  17. New high power CW klystrons at TED

    Beunas, A; Marchesin, R

    2003-01-01

    Thales Electron Devices (TED) has been awarded a contract by CERN to develop and produce 20 units of the klystrons needed to feed the Large Hadrons Collider (LHC). Each of these delivers 300 kW of CW RF power at 400 MHz. Three klystrons have been delivered to CERN up to now.

  18. High-voltage, high-power architecture considerations

    Moser, R.L.

    1985-01-01

    Three basic EPS architectures, direct energy transfer, peak-power tracking, and a potential EPS architecture for a nuclear reactor are described and compared. Considerations for the power source and energy storage are discussed. Factors to be considered in selecting the operating voltage are pointed out. Other EPS architecture considerations are autonomy, solar array degrees of freedom, and EPS modularity. It was concluded that selection of the power source and energy storage has major impacts on the spacecraft architecture and mass

  19. Development of Hollow Cathode of High Power Middle Pressure Arcjet

    Vaulin, Eujeni

    1995-01-01

    ...: Determine integral performances of arcjet devices in nitrogen, ammonia, and their mixtures using hollow cathode devices at low and high current levels, perform short term tests (up to 50 hours...

  20. Modelling aluminium wire bond reliability in high power OMP devices

    Kregting, R.; Yuan, C.A.; Xiao, A.; Bruijn, F. de

    2011-01-01

    In a RF power application such as the OMP, the wires are subjected to high current (because of the high power) and high temperature (because of the heat from IC and joule-heating from the wire itself). Moreover, the wire shape is essential to the RF performance. Hence, the aluminium wire is

  1. Interaction of high power ultrashort laser pulses with plasmas

    Geissler, M.

    2000-12-01

    The invention of short laser-pulses has opened a vast application range from testing ultra high-speed semiconductor devices to precision material processing, from triggering and tracing chemical reactions to sophisticated surgical applications in opthalmology and neurosurgery. In physical science, ultrashort light pulses enable researchers to follow ultrafast relaxation processes in the microcosm on time scale never before accessible and study light-matter-interactions at unprecedented intensity levels. The aim of this thesis is to investigate the interaction of ultrashort high power laser pulses with plasmas for a broad intensity range. First the ionization of atoms with intense laser fields is investigated. For sufficient strong and low frequent laser pulses, electrons can be removed from the core by a tunnel process through a potential barrier formed by the electric field of the laser. This mechanism is described by a well-established theory, but the interaction of few-cycle laser pulses with atoms can lead to regimes where the tunnel theory loses its validity. This regime is investigated and a new description of the ionization is found. Although the ionization plays a major role in many high-energy laser processes, there exist no simple and complete model for the evolution of laser pulses in field-ionizing media. A new propagation equation and the polarization response for field-ionizing media are presented and the results are compared with experimental data. Further the interaction of high power laser radiation with atoms result in nonlinear response of the electrons. The spectrum of this induced nonlinear dipole moment reaches beyond visible wavelengths into the x-ray regime. This effect is known as high harmonic generation (HHG) and is a promising tool for the generation of coherent shot wavelength radiation, but the conversions are still not efficient enough for most practical applications. Phase matching schemes to overcome the limitation are discussed

  2. GaN-based High Power High Frequency Wide Range LLC Resonant Converter, Phase I

    National Aeronautics and Space Administration — SET Group will design, build and demonstrate a Gallium Nitride (GaN) based High Power High Frequency Wide Range LLC Resonant Converter capable of handling high power...

  3. Effectiveness of mouse minute virus inactivation by high temperature short time treatment technology: a statistical assessment.

    Murphy, Marie; Quesada, Guillermo Miro; Chen, Dayue

    2011-11-01

    Viral contamination of mammalian cell cultures in GMP manufacturing facility represents a serious safety threat to biopharmaceutical industry. Such adverse events usually require facility shutdown for cleaning/decontamination, and thus result in significant loss of production and/or delay of product development. High temperature short time (HTST) treatment of culture media has been considered as an effective method to protect GMP facilities from viral contaminations. Log reduction factor (LRF) has been commonly used to measure the effectiveness of HTST treatment for viral inactivation. However, in order to prevent viral contaminations, HTST treatment must inactivate all infectious viruses (100%) in the medium batch since a single virus is sufficient to cause contamination. Therefore, LRF may not be the most appropriate indicator for measuring the effectiveness of HTST in preventing viral contaminations. We report here the use of the probability to achieve complete (100%) virus inactivation to assess the effectiveness of HTST treatment. By using mouse minute virus (MMV) as a model virus, we have demonstrated that the effectiveness of HTST treatment highly depends upon the level of viral contaminants in addition to treatment temperature and duration. We believe that the statistical method described in this report can provide more accurate information about the power and potential limitation of technologies such as HTST in our shared quest to mitigate the risk of viral contamination in manufacturing facilities. Copyright © 2011 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  4. Los Alamos high-power proton linac designs

    Lawrence, G.P. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

  5. Performance of a high efficiency high power UHF klystron

    Konrad, G.T.

    1977-03-01

    A 500 kW c-w klystron was designed for the PEP storage ring at SLAC. The tube operates at 353.2 MHz, 62 kV, a microperveance of 0.75, and a gain of approximately 50 dB. Stable operation is required for a VSWR as high as 2 : 1 at any phase angle. The design efficiency is 70%. To obtain this value of efficiency, a second harmonic cavity is used in order to produce a very tightly bunched beam in the output gap. At the present time it is planned to install 12 such klystrons in PEP. A tube with a reduced size collector was operated at 4% duty at 500 kW. An efficiency of 63% was observed. The same tube was operated up to 200 kW c-w for PEP accelerator cavity tests. A full-scale c-w tube reached 500 kW at 65 kV with an efficiency of 55%. In addition to power and phase measurements into a matched load, some data at various load mismatches are presented

  6. Temperature Stabilized Characterization of High Voltage Power Supplies

    Krarup, Ole

    2017-01-01

    High precision measurements of the masses of nuclear ions in the ISOLTRAP experiment relies on an MR-ToF. A major source of noise and drift is the instability of the high voltage power supplies employed. Electrical noise and temperature changes can broaden peaks in time-of-flight spectra and shift the position of peaks between runs. In this report we investigate how the noise and drift of high-voltage power supplies can be characterized. Results indicate that analog power supplies generally have better relative stability than digitally controlled ones, and that the high temperature coefficients of all power supplies merit efforts to stabilize them.

  7. Fusion blankets for high efficiency power cycles

    Powell, J.R.; Fillo, J.A.; Horn, F.L.; Lazareth, O.W.; Usher, J.L.

    1980-04-01

    Definitions are given of 10 generic blanket types and the specific blanket chosen to be analyzed in detail from each of the 10 types. Dimensions, compositions, energy depositions and breeding ratios (where applicable) are presented for each of the 10 designs. Ultimately, based largely on neutronics and thermal hyraulics results, breeding an nonbreeding blanket options are selected for further design analysis and integration with a suitable power conversion subsystem

  8. Compact electro-thermal modeling of a SiC MOSFET power module under short-circuit conditions

    Ceccarelli, Lorenzo; Reigosa, Paula Diaz; Bahman, Amir Sajjad

    2017-01-01

    A novel physics-based, electro-thermal model which is capable of estimating accurately the short-circuit behavior and thermal instabilities of silicon carbide MOSFET multi-chip power modules is proposed in this paper. The model has been implemented in PSpice and describes the internal structure.......2 kV breakdown voltage and about 300 A rated current. The short-circuit behavior of the module is investigated experimentally through a non-destructive test setup and the model is validated. The estimation of overcurrent and temperature distribution among the chips can provide useful information...

  9. Power affects performance when the pressure is on: evidence for low-power threat and high-power lift.

    Kang, Sonia K; Galinsky, Adam D; Kray, Laura J; Shirako, Aiwa

    2015-05-01

    The current research examines how power affects performance in pressure-filled contexts. We present low-power-threat and high-power-lift effects, whereby performance in high-stakes situations suffers or is enhanced depending on one's power; that is, the power inherent to a situational role can produce effects similar to stereotype threat and lift. Three negotiations experiments demonstrate that role-based power affects outcomes but only when the negotiation is diagnostic of ability and, therefore, pressure-filled. We link these outcomes conceptually to threat and lift effects by showing that (a) role power affects performance more strongly when the negotiation is diagnostic of ability and (b) underperformance disappears when the low-power negotiator has an opportunity to self-affirm. These results suggest that stereotype threat and lift effects may represent a more general phenomenon: When the stakes are raised high, relative power can act as either a toxic brew (stereotype/low-power threat) or a beneficial elixir (stereotype/high-power lift) for performance. © 2015 by the Society for Personality and Social Psychology, Inc.

  10. A Dynamic Programming based method for optimizing power system restoration with high wind power penetration

    Hu, Rui; Hu, Weihao; Li, Pengfei

    2016-01-01

    and relatively low cost. Thus, many countries are increasing the wind power penetration in their power system step by step, such as Denmark, Spain and Germany. The incremental wind power penetration brings a lot of new issues in operation and programming. The power system sometimes will operate close to its...... stable limits. Once the blackout happens, a well-designed restoration strategy is significant. This paper focuses on how to ameliorate the power system restoration procedures to adapt the high wind power penetration and how to take full advantages of the wind power plants during the restoration....... In this paper, the possibility to exploit the stochastic wind power during restoration was discussed, and a Dynamic Programming (DP) method was proposed to make wind power contribute in the restoration rationally as far as possible. In this paper, the method is tested and verified by a modified IEEE 30 Buses...

  11. High-frequency high-voltage high-power DC-to-DC converters

    Wilson, T. G.; Owen, H. A.; Wilson, P. M.

    1982-09-01

    A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

  12. Intelligent and robust prediction of short term wind power using genetic programming based ensemble of neural networks

    Zameer, Aneela; Arshad, Junaid; Khan, Asifullah; Raja, Muhammad Asif Zahoor

    2017-01-01

    Highlights: • Genetic programming based ensemble of neural networks is employed for short term wind power prediction. • Proposed predictor shows resilience against abrupt changes in weather. • Genetic programming evolves nonlinear mapping between meteorological measures and wind-power. • Proposed approach gives mathematical expressions of wind power to its independent variables. • Proposed model shows relatively accurate and steady wind-power prediction performance. - Abstract: The inherent instability of wind power production leads to critical problems for smooth power generation from wind turbines, which then requires an accurate forecast of wind power. In this study, an effective short term wind power prediction methodology is presented, which uses an intelligent ensemble regressor that comprises Artificial Neural Networks and Genetic Programming. In contrast to existing series based combination of wind power predictors, whereby the error or variation in the leading predictor is propagated down the stream to the next predictors, the proposed intelligent ensemble predictor avoids this shortcoming by introducing Genetical Programming based semi-stochastic combination of neural networks. It is observed that the decision of the individual base regressors may vary due to the frequent and inherent fluctuations in the atmospheric conditions and thus meteorological properties. The novelty of the reported work lies in creating ensemble to generate an intelligent, collective and robust decision space and thereby avoiding large errors due to the sensitivity of the individual wind predictors. The proposed ensemble based regressor, Genetic Programming based ensemble of Artificial Neural Networks, has been implemented and tested on data taken from five different wind farms located in Europe. Obtained numerical results of the proposed model in terms of various error measures are compared with the recent artificial intelligence based strategies to demonstrate the

  13. High power s-band vacuum load

    Neubauer, Michael [Muons, Inc., Batavia, IL (United States); Dudas, Alan [Muons, Inc., Batavia, IL (United States); Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-29

    Through a combination of experimentation and calculation the components of a novel room temperature dry load were successfully fabricated. These components included lossy ceramic cylinders of various lengths, thicknesses, and percent of silicon carbide (SiC). The cylinders were then assembled into stainless steel compression rings by differential heating of the parts and a special fixture. Post machining of this assembly provided a means for a final weld. The ring assemblies were then measured for S-parameters, individually and in pairs using a low-cost TE10 rectangular to TE01 circular waveguide adapter specially designed to be part of the final load assembly. Matched pairs of rings were measured for assembly into the final load, and a sliding short designed and fabricated to assist in determining the desired short location in the final assembly. The plan for the project was for Muons, Inc. to produce prototype loads for long-term testing at SLAC. The STTR funds for SLAC were to upgrade and operate their test station to ensure that the loads would satisfy their requirements. Phase III was to be the sale to SLAC of loads that Muons, Inc. would manufacture. However, an alternate solution that involved a rebuild of the old loads, reduced SLAC budget projections, and a relaxed time for the replacement of all loads meant that in-house labor will be used to do the upgrade without the need for the loads developed in this project. Consequently, the project was terminated before the long term testing was initiated. However, SLAC can use the upgraded test stand to compare the long-term performance of the ones produced in this project with their rebuilt loads when they are available.

  14. High power s-band vacuum load

    Neubauer, Michael; Dudas, Alan; Krasnykh, Anatoly

    2016-01-01

    Through a combination of experimentation and calculation the components of a novel room temperature dry load were successfully fabricated. These components included lossy ceramic cylinders of various lengths, thicknesses, and percent of silicon carbide (SiC). The cylinders were then assembled into stainless steel compression rings by differential heating of the parts and a special fixture. Post machining of this assembly provided a means for a final weld. The ring assemblies were then measured for S-parameters, individually and in pairs using a low-cost TE10 rectangular to TE01 circular waveguide adapter specially designed to be part of the final load assembly. Matched pairs of rings were measured for assembly into the final load, and a sliding short designed and fabricated to assist in determining the desired short location in the final assembly. The plan for the project was for Muons, Inc. to produce prototype loads for long-term testing at SLAC. The STTR funds for SLAC were to upgrade and operate their test station to ensure that the loads would satisfy their requirements. Phase III was to be the sale to SLAC of loads that Muons, Inc. would manufacture. However, an alternate solution that involved a rebuild of the old loads, reduced SLAC budget projections, and a relaxed time for the replacement of all loads meant that in-house labor will be used to do the upgrade without the need for the loads developed in this project. Consequently, the project was terminated before the long term testing was initiated. However, SLAC can use the upgraded test stand to compare the long-term performance of the ones produced in this project with their rebuilt loads when they are available.

  15. New high power 200 MHz RF system for the LANSCE drift tube linac

    Lyles, J.; Friedrichs, C.; Lynch, M.

    1998-01-01

    The Los Alamos Neutron Science Center (LANSCE) linac provides an 800 MeV direct H + proton beam, and injects H - to the upgraded proton storage ring for charge accumulation for the Short Pulse Spallation Source. Accelerating these interlaced beams requires high average power from the 201.25 MHz drift tube linac (DTL) RF system. Three power amplifiers have operated at up to three Megawatts with 12% duty factor. The total number of electron power tubes in the RF amplifiers and their modulators has been reduced from fifty-two to twenty-four. The plant continues to utilize the original design of a tetrode driving a super power triode. Further increases in the linac duty factor are limited, in part, by the maximum dissipation ratings of the triodes. A description of the system modifications proposed to overcome these limitations includes new power amplifiers using low-level RF modulation for tank field control. The first high power Diacrode reg-sign is being delivered and a new amplifier cavity is being designed. With only eight power tubes, the new system will deliver both peak power and high duty factor, with lower mains power and cooling requirements. The remaining components needed for the new RF system will be discussed

  16. Experimental investigation of steep-front short duration (SFSD) surge effects on power systems components

    Miller, D.B. (Mississippi State Univ., MS (United States). Dept. of Electrical and Computer Engineering)

    1992-05-01

    Results are reported from experiments in which steep-front, short- duration (SFSD) voltage impulses were imposed on various electrical distribution components. These pulses were generated by switching a section of charged, high voltage coaxial cable across the component under study. Components included underground distribution cable, terminators, insulators and arresters. SFSD voltage needed to flashover 15 kV polyethylene cable with a single pulse is approximately 625 kV peak. Strength of polyethylene cable decreases with increasing number of SFSD pulses, indicating cumulative degradation of the polymer. For 15 kV and 25 kV cable terminators, the SFSD CFO was over twice the rated standard lightning BIL for the same units. Similarly, porcelain suspension insulators required more than a doubling of voltage to decrease time to flashover from 1 microsecond to .1 microsecond. Arresters were found to respond rapidly to steep-front current pulses, but the arrester material itself was found to result in a higher discharge voltage for SFSD pulses. Arresters also showed a delay in turn-on of current following the arrival of a steep-front voltage surge.

  17. Effects of massive wind power integration on short-term water resource management in central Chile - a grid-wide study

    Haas, J.; Olivares, M. A.; Palma, R.

    2013-12-01

    In central Chile, water from reservoirs and streams is mainly used for irrigation and power generation. Hydropower reservoirs operation is particularly challenging because: i) decisions at each plant impact the entire power system, and ii) the existence of large storage capacity implies inter-temporal ties. An Independent System Operator (ISO) decides the grid-wide optimal allocation of water for power generation, under irrigation-related constraints. To account for the long-term opportunity cost of water, a future cost function is determined and used in the short term planning. As population growth and green policies demand increasing levels of renewable energy in power systems, deployment of wind farms and solar plants is rising quickly. However, their power output is highly fluctuating on short time scales, affecting the operation of power plants, particularly those fast responding units as hydropower reservoirs. This study addresses these indirect consequences of massive introduction of green energy sources on reservoir operations. Short-term reservoir operation, under different wind penetration scenarios, is simulated using a replica of Chile's ISO's scheduling optimization tools. Furthermore, an ongoing study is exploring the potential to augment the capacity the existing hydro-power plants to better cope with the balancing needs due to a higher wind power share in the system. As reservoir releases determine to a great extent flows at downstream locations, hourly time series of turbined flows for 24-hour periods were computed for selected combinations between new wind farms and increased capacity of existing hydropower plants. These time series are compiled into subdaily hydrologic alteration (SDHA) indexes (Zimmerman et al, 2010). The resulting sample of indexes is then analyzed using duration curves. Results show a clear increase in the SDHA for every reservoir of the system as more fluctuating renewables are integrated into the system. High

  18. Just Trust Us: A Short History of Emergency Powers and Constitutional Change

    de Wilde, M.

    2015-01-01

    This article focuses on the relationship between governmental emergency power (ie, the power to derogate from the laws in emergencies) and constitutional change. It seeks to explain how, in the past, uses of emergency power contributed to constitutional transformations. Three historical examples are

  19. Sexual aggression when power is new: Effects of acute high power on chronically low-power individuals.

    Williams, Melissa J; Gruenfeld, Deborah H; Guillory, Lucia E

    2017-02-01

    Previous theorists have characterized sexually aggressive behavior as an expression of power, yet evidence that power causes sexual aggression is mixed. We hypothesize that power can indeed create opportunities for sexual aggression-but that it is those who chronically experience low power who will choose to exploit such opportunities. Here, low-power men placed in a high-power role showed the most hostility in response to a denied opportunity with an attractive woman (Studies 1 and 2). Chronically low-power men and women given acute power were the most likely to say they would inappropriately pursue an unrequited workplace attraction (Studies 3 and 4). Finally, having power over an attractive woman increased harassment behavior among men with chronic low, but not high, power (Study 5). People who see themselves as chronically denied power appear to have a stronger desire to feel powerful and are more likely to use sexual aggression toward that end. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  20. Prospects for development of powerful, highly efficient, relativistic gyrodevices

    Nusinovich, G.S.; Granatstein, V.L.

    1992-01-01

    For various applications the required parameters of sources of powerful microwave radiation lie far beyond the capabilities of existing tubes. This provokes an interest in reconsidering basic principles of relevant microwave sources in order to search for alternative concepts in their development. One of the most promising devices in the short-wavelength region of microwaves is the cyclotron resonance maser (CRM). During the last decade, two important varieties of CRMs have been distinguished, namely, gyrotrons, which operate at frequencies close to cut-off, and cyclotron autoresonance masers (CARMs), which operate at frequencies far from cut-off. When the axial phase velocity of the wave in properly adjusted to the beam voltage and electron pitch-ratio, the efficiency of relativistic CRMs may be high (≥50%). The method of optimizing efficiency based on a partial compensation of the shift in the relativistic electron cyclotron frequency by the change in the Doppler term can be, in principle, accompanied by a corresponding profiling of the external magnetic field and/or the wave phase velocity in a slightly irregular waveguide. These methods can be used in such relativistic CRMs as relativistic gyrotrons, gyroklystrons, gyro-traveling-wave-tubes and gyrotwistrons. The most important point is their sensitivity to a spread in electron parameters. As the beam voltage grows, the operation becomes more sensitive. However, at relatively low voltages such devices are quite tolerant to electron velocity spread

  1. High performance magnet power supply optimization

    Jackson, L.T.

    1988-01-01

    The power supply system for the joint LBL--SLAC proposed accelerator PEP provides the opportunity to take a fresh look at the current techniques employed for controlling large amounts of dc power and the possibility of using a new one. A basic requirement of +- 100 ppM regulation is placed on the guide field of the bending magnets and quadrupoles placed around the 2200 meter circumference of the accelerator. The optimization questions to be answered by this paper are threefold: Can a firing circuit be designed to reduce the combined effects of the harmonics and line voltage combined effects of the harmonics and line voltage unbalance to less than 100 ppM in the magnet field. Given the ambiguity of the previous statement, is the addition of a transistor bank to a nominal SCR controlled system the way to go or should one opt for an SCR chopper system running at 1 KHz where multiple supplies are fed from one large dc bus and the cost--performance evaluation of the three possible systems

  2. Low reflectance high power RF load

    Ives, R. Lawrence; Mizuhara, Yosuke M.

    2016-02-02

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  3. An ultra-high discrimination Y chromosome short tandem repeat multiplex DNA typing system.

    Erin K Hanson

    Full Text Available In forensic casework, Y chromosome short tandem repeat markers (Y-STRs are often used to identify a male donor DNA profile in the presence of excess quantities of female DNA, such as is found in many sexual assault investigations. Commercially available Y-STR multiplexes incorporating 12-17 loci are currently used in forensic casework (Promega's PowerPlex Y and Applied Biosystems' AmpFlSTR Yfiler. Despite the robustness of these commercial multiplex Y-STR systems and the ability to discriminate two male individuals in most cases, the coincidence match probabilities between unrelated males are modest compared with the standard set of autosomal STR markers. Hence there is still a need to develop new multiplex systems to supplement these for those cases where additional discriminatory power is desired or where there is a coincidental Y-STR match between potential male participants. Over 400 Y-STR loci have been identified on the Y chromosome. While these have the potential to increase the discrimination potential afforded by the commercially available kits, many have not been well characterized. In the present work, 91 loci were tested for their relative ability to increase the discrimination potential of the commonly used 'core' Y-STR loci. The result of this extensive evaluation was the development of an ultra high discrimination (UHD multiplex DNA typing system that allows for the robust co-amplification of 14 non-core Y-STR loci. Population studies with a mixed African American and American Caucasian sample set (n = 572 indicated that the overall discriminatory potential of the UHD multiplex was superior to all commercial kits tested. The combined use of the UHD multiplex and the Applied Biosystems' AmpFlSTR Yfiler kit resulted in 100% discrimination of all individuals within the sample set, which presages its potential to maximally augment currently available forensic casework markers. It could also find applications in human evolutionary

  4. High-Specificity Targeted Functional Profiling in Microbial Communities with ShortBRED.

    James Kaminski

    2015-12-01

    Full Text Available Profiling microbial community function from metagenomic sequencing data remains a computationally challenging problem. Mapping millions of DNA reads from such samples to reference protein databases requires long run-times, and short read lengths can result in spurious hits to unrelated proteins (loss of specificity. We developed ShortBRED (Short, Better Representative Extract Dataset to address these challenges, facilitating fast, accurate functional profiling of metagenomic samples. ShortBRED consists of two components: (i a method that reduces reference proteins of interest to short, highly representative amino acid sequences ("markers" and (ii a search step that maps reads to these markers to quantify the relative abundance of their associated proteins. After evaluating ShortBRED on synthetic data, we applied it to profile antibiotic resistance protein families in the gut microbiomes of individuals from the United States, China, Malawi, and Venezuela. Our results support antibiotic resistance as a core function in the human gut microbiome, with tetracycline-resistant ribosomal protection proteins and Class A beta-lactamases being the most widely distributed resistance mechanisms worldwide. ShortBRED markers are applicable to other homology-based search tasks, which we demonstrate here by identifying phylogenetic signatures of antibiotic resistance across more than 3,000 microbial isolate genomes. ShortBRED can be applied to profile a wide variety of protein families of interest; the software, source code, and documentation are available for download at http://huttenhower.sph.harvard.edu/shortbred.

  5. In-volume heating using high-power laser diodes

    Denisenkov, V.S.; Kiyko, V.V.; Vdovin, G.V.

    2015-01-01

    High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface

  6. High-power sputtering employed for film deposition

    Shapovalov, V I

    2017-01-01

    The features of high-power magnetron sputtering employed for the films’ deposition are reviewed. The main physical phenomena accompanying high-power sputtering including ion-electron emission, gas rarefaction, ionization of sputtered atoms, self-sputtering, ion sound waves and the impact of the target heating are described. (paper)

  7. Active Snubber Circuit for High Power Inverter Leg

    Rasmussen, Tonny Wederberg; Johansen, Morten Holst

    2009-01-01

    Abstract— High power converters in the conventional 6 pulse configuration with 6 switching elements IGBTs (Insulated Gate Bipolar Transistor) are pushed to the limit of power. Especially the switching loss is high. This reduces the switching frequency due to cooling problems. Passive snubber circ...

  8. Improved cutting performance in high power laser cutting

    Olsen, Flemming Ove

    2003-01-01

    Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described.......Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described....

  9. High-power microwave diplexers for advanced ECRH systems

    Kasparek, W.; Petelin, M.; Erckmann, V.; Bruschi, A.; Noke, F.; Purps, F.; Hollmann, F.; Koshurinov, Y.; Lubyako, L.; Plaum, B.; Wubie, W.

    2009-01-01

    In electron cyclotron resonance heating systems, high-power multiplexers can be employed as power combiners, adjustable power dividers, fast switches to toggle the power between two launchers, as well as frequency sensitive directional couplers to combine heating and diagnostic applications on one launcher. In the paper, various diplexer designs for quasi-optical and corrugated waveguide transmission systems are discussed. Numerical calculations, low-power tests and especially high-power experiments performed at the ECRH system of W7-X are shown, which demonstrate the capability of these devices. Near term plans for applications on ASDEX Upgrade and FTU are presented. Based on the present results, options for implementation of power combiners and fast switches in the ECRH system of ITER is discussed.

  10. High-precision GNSS ocean positioning with BeiDou short-message communication

    Li, Bofeng; Zhang, Zhiteng; Zang, Nan; Wang, Siyao

    2018-04-01

    The current popular GNSS RTK technique would be not applicable on ocean due to the limited communication access for transmitting differential corrections. A new technique is proposed for high-precision ocean RTK, referred to as ORTK, where the corrections are transmitted by employing the function of BeiDou satellite short-message communication (SMC). To overcome the limitation of narrow bandwidth of BeiDou SMC, a new strategy of simplifying and encoding corrections is proposed instead of standard differential corrections, which reduces the single-epoch corrections from more than 1000 to less than 300 bytes. To solve the problems of correction delays, cycle slips, blunders and abnormal epochs over ultra-long baseline ORTK, a series of powerful algorithms were designed at the user-end software for achieving the stable and precise kinematic solutions on far ocean applications. The results from two long baselines of 240 and 420 km and real ocean experiments reveal that the kinematic solutions with horizontal accuracy of 5 cm and vertical accuracy of better than 15 cm are achievable by convergence time of 3-10 min. Compared to commercial ocean PPP with satellite telecommunication, ORTK is of much cheaper expense, higher accuracy and shorter convergence. It will be very prospective in many location-based ocean services.

  11. High rate gamma spectroscopy system for activation analysis of short-lived isomeric transitions

    Westphall, G P [Atominstitut der Oesterreichischen Hochschulen, Vienna

    1976-07-15

    A high rate spectroscopy system specially suited for measurement of short-lived isomeric transitions is described, which, as part of a fast activation analysis facility at the TRIGA Mark II reactor, provides for automatic recording and immediate evaluation of gamma spectra taken from nuclides activated at stationary or pulsed reactor power. The system consists of a commercial de-coupled Ge(Li)-detector of 70 cm/sup 3/ modified for recycling operation for input rates in excess of 500000 c/s /sup 60/Co, a time variant trapezoidal shaping section and a fast constant dead-time ADC coupled to a programmed multichannel analyzer. Novel circuits for efficient pile-up rejection and time variant base line restoration extend the concept of gated integration up to count rates of more than 200000 c/s /sup 60/Co. Time-sequenced recording of spectra is performed by a minicomputer operated as a front-end processor of a larger laboratory computer, where final data processing takes place. New concepts for very simple and cost-effective implementation of multichannel analyzers by means of general purpose small computers are described.

  12. A high rate gamma spectroscopy system for activation analysis of short lived isomeric transitions

    Westphal, G P [Atominstitut, Vienna (Austria)

    1976-07-01

    A high rate spectroscopy system specially suited for measurement of short-lived isomeric transitions is described, which, as part of a fast activation analysis facility at the TRIGA Mark II reactor, provides for automatic recording and immediate evaluation of gamma spectra taken from nuclides activated at stationary or pulsed reactor power. The system consists of a commercial DC-coupled Ge(Li)-detector of 70 cm{sup 3} modified for recycling operation for input rates in excess of 500,000 c/s Co-60, a time variant trapezoidal shaping section and a fast constant dead-time ADC coupled to a programmed multi-channel analyzer. Novel circuits for efficient pile-up rejection and time variant base line restoration extend the concept of gated integration up to count rates of more than 300,000 c/s Co-60. Time-sequenced recording of spectra is performed by a mini computer operated as a front-end processor of a larger laboratory computer, where final data processing takes place. New concepts for very simple and cost-effective implementation of multi-channel analyzers by means of general purpose small computers are described. (author)

  13. High Average Power Fiber Laser for Satellite Communications, Phase I

    National Aeronautics and Space Administration — Very high average power lasers with high electrical-top-optical (E-O) efficiency, which also support pulse position modulation (PPM) formats in the MHz-data rate...

  14. High Performance Auxiliary Power Unit Technology Demonstrator.

    1980-12-01

    aft bearings 1.13 P3 - Power producer CDP 1.14 DPHE - Lube pressure drop at heat exchanger 1.15 POFP - Load airflow orifice pressure 1.16 DPOFP - Load...P𔃽I -PSI G PEBL -PSIG P2 -PS.IG DPHE -PID POFP -F Iu 0. 022±_ 77. 3478 6o5. 6 4±4 ±8L-. 4852 19. 51-17.4 DPOFP -PSID Ni -,. N2-i -RPM NSATM -FPM...28. 0250 83. 3505 29. 861 1:9. 7680 PGi -PSIG PEBL -PSIG P3 -PSIG DPHE -PSID POFP -PSIG 0. 0100 77. 9199 72.4862 17. 25 ±19. 4122 1= DPOFP -PSID NI

  15. On the interplay between short and long term memory in the power-law cross-correlations setting

    Krištoufek, Ladislav

    2015-01-01

    Roč. 421, č. 1 (2015), s. 218-222 ISSN 0378-4371 R&D Projects: GA ČR(CZ) GP14-11402P Institutional support: RVO:67985556 Keywords : Power-law cross-correlations * Long term memory * Short term memory Subject RIV: AH - Economics Impact factor: 1.785, year: 2015 http://library.utia.cas.cz/separaty/2015/E/kristoufek-0452316.pdf

  16. High Efficiency, High Temperature Foam Core Heat Exchanger for Fission Surface Power Systems, Phase II

    National Aeronautics and Space Administration — Fission-based power systems with power levels of 30 to ≥100 kWe will be needed for planetary surface bases. Development of high temperature, high efficiency heat...

  17. Design and development of power supplies for high power IOT based RF amplifier

    Kumar, Yashwant; Kumari, S.; Ghosh, M.K.; Bera, A.; Sadhukhan, A.; Pal, S.S.; Khare, V.K.; Tiwari, T.P.; Thakur, S.K.; Saha, S.

    2013-01-01

    Design, development, circuit topology, function of system components and key system specifications of different power supplies for biasing electrodes of Thales Inductive Output Tube (IOT) based high power RF amplifier are presented in this paper. A high voltage power supply (-30 kV, 3.2A dc) with fast (∼microsecond) crowbar protection circuit is designed, developed and commissioned at VECC for testing the complete setup. Other power supplies for biasing grid electrode (300V, 0.5A dc) and Ion Pump (3 kV, 0.1mA dc) of IOT are also designed, developed and tested with actual load. A HV Deck (60kV Isolation) is specially designed in house to place these power supplies which are floating at 30 kV. All these power supplies are powered by an Isolation Transformer (5 kVA, 60 kV isolation) designed and developed in VECC. (author)

  18. Design of The High Efficiency Power Factor Correction Circuit for Power Supply

    Atiye Hülya OBDAN

    2017-12-01

    Full Text Available Designing power factor correction circuits for switched power supplies has become important in recent years in terms of efficient use of energy. Power factor correction techniques play a significant role in high power density and energy efficiency. For these purposes, bridgeless PFC topologies and control strategies have been developed alongside basic boost PFC circuits. The power density can be increased using bridgeless structures by means of reducing losses in the circuit. This article examines bridgeless PFC structures and compares their performances in terms of losses and power factor. A semi-bridgeless PFC, which is widely used at high power levels, was analyzed and simulated. The designed circuit simulation using the current mode control method was performed in the PSIM program. A prototype of a 900 W semi-bridgeless PFC circuit was implemented and the results obtained from the circuit are presented

  19. Cascade: a high-efficiency ICF power reactor

    Pitts, J.H.

    1985-01-01

    Cascade attains a net power-plant efficiency of 49% and its cost is competitive with high-temperature gas-cooled reactor, pressurized-water reactor, and coal-fired power plants. The Cascade reactor and blanket are made of ceramic materials and activation is 6 times less than that of the MARS Tandem Mirror Reactor operating at comparable power. Hands-on maintenance of the heat exchangers is possible one day after shutdown. Essentially all tritium is recovered in the vacuum system, with the remainder recovered from the helium power conversion loop. Tritium leakage external to the vacuum system and power conversion loop is only 0.03 Ci/d

  20. On the Ongoing Evolution of Very High Frequency Power Supplies

    Knott, Arnold; Andersen, Toke Meyer; Kamby, Peter

    2013-01-01

    The ongoing demand for smaller and lighter power supplies is driving the motivation to increase the switching frequencies of power converters. Drastic increases however come along with new challenges, namely the increase of switching losses in all components. The application of power circuits used...... in radio frequency transmission equipment helps to overcome those. However those circuits were not designed to meet the same requirements as power converters. This paper summarizes the contributions in recent years in application of very high frequency (VHF) technologies in power electronics, describes...

  1. ISRNA: an integrative online toolkit for short reads from high-throughput sequencing data.

    Luo, Guan-Zheng; Yang, Wei; Ma, Ying-Ke; Wang, Xiu-Jie

    2014-02-01

    Integrative Short Reads NAvigator (ISRNA) is an online toolkit for analyzing high-throughput small RNA sequencing data. Besides the high-speed genome mapping function, ISRNA provides statistics for genomic location, length distribution and nucleotide composition bias analysis of sequence reads. Number of reads mapped to known microRNAs and other classes of short non-coding RNAs, coverage of short reads on genes, expression abundance of sequence reads as well as some other analysis functions are also supported. The versatile search functions enable users to select sequence reads according to their sub-sequences, expression abundance, genomic location, relationship to genes, etc. A specialized genome browser is integrated to visualize the genomic distribution of short reads. ISRNA also supports management and comparison among multiple datasets. ISRNA is implemented in Java/C++/Perl/MySQL and can be freely accessed at http://omicslab.genetics.ac.cn/ISRNA/.

  2. Eighth CW and High Average Power RF Workshop

    2014-01-01

    We are pleased to announce the next Continuous Wave and High Average RF Power Workshop, CWRF2014, to take place at Hotel NH Trieste, Trieste, Italy from 13 to 16 May, 2014. This is the eighth in the CWRF workshop series and will be hosted by Elettra - Sincrotrone Trieste S.C.p.A. (www.elettra.eu). CWRF2014 will provide an opportunity for designers and users of CW and high average power RF systems to meet and interact in a convivial environment to share experiences and ideas on applications which utilize high-power klystrons, gridded tubes, combined solid-state architectures, high-voltage power supplies, high-voltage modulators, high-power combiners, circulators, cavities, power couplers and tuners. New ideas for high-power RF system upgrades and novel ways of RF power generation and distribution will also be discussed. CWRF2014 sessions will start on Tuesday morning and will conclude on Friday lunchtime. A visit to Elettra and FERMI will be organized during the workshop. ORGANIZING COMMITTEE (OC): Al...

  3. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

  4. Short-term spatio-temporal wind power forecast in robust look-ahead power system dispatch

    Xie, Le

    2014-01-01

    We propose a novel statistical wind power forecast framework, which leverages the spatio-temporal correlation in wind speed and direction data among geographically dispersed wind farms. Critical assessment of the performance of spatio-temporal wind power forecast is performed using realistic wind farm data from West Texas. It is shown that spatio-temporal wind forecast models are numerically efficient approaches to improving forecast quality. By reducing uncertainties in near-term wind power forecasts, the overall cost benefits on system dispatch can be quantified. We integrate the improved forecast with an advanced robust look-ahead dispatch framework. This integrated forecast and economic dispatch framework is tested in a modified IEEE RTS 24-bus system. Numerical simulation suggests that the overall generation cost can be reduced by up to 6% using a robust look-ahead dispatch coupled with spatio-temporal wind forecast as compared with persistent wind forecast models. © 2013 IEEE.

  5. Detecting the single line to ground short circuit fault in the submarine’s power system using the artificial neural network

    Behniafar Ali

    2013-01-01

    Full Text Available The electric marine instruments are newly inserted in the trade and industry, for which the existence of an equipped and reliable power system is necessitated. One of the features of such a power system is that it cannot have an earth system causing the protection relays not to be able to detect the single line to ground short circuit fault. While on the other hand, the occurrence of another similar fault at the same time can lead to the double line fault and thereby the tripping of relays and shortening of vital loads. This in turn endangers the personals' security and causes the loss of military plans. From the above considerations, it is inferred that detecting the single line to ground fault in the marine instruments is of a special importance. In this way, this paper intends to detect the single line to ground fault in the power systems of the marine instruments using the wavelet transform and Multi-Layer Perceptron (MLP neural network. In the numerical analysis, several different types of short circuit faults are simulated on several marine power systems and the proposed approach is applied to detect the single line to ground fault. The results are of a high quality and preciseness and perfectly demonstrate the effectiveness of the proposed approach.

  6. Benefits for wind energy in electricity markets from using short term wind power prediction tools: a simulation study

    Usaola, J.; Ravelo, O.; Gonzalez, G.; Soto, F.; Davila, M.C.; Diaz-Guerra, B.

    2004-01-01

    One of the characteristics of wind energy, from the grid point of view, is its non-dispatchability, i.e. generation cannot be ordered, hence integration in electrical networks may be difficult. Short-term wind power prediction-tools could make this integration easier, either by their use by the grid System Operator, or by promoting the participation of wind farms in the electricity markets and using prediction tools to make their bids in the market. In this paper, the importance of a short-term wind power-prediction tool for the participation of wind energy systems in electricity markets is studied. Simulations, according to the current Spanish market rules, have been performed to the production of different wind farms, with different degrees of accuracy in the prediction tool. It may be concluded that income from participation in electricity markets is increased using a short-term wind power prediction-tool of average accuracy. This both marginally increases income and also reduces the impact on system operation with the improved forecasts. (author)

  7. The research on high power transducer

    Zhao Wuling; Li Yubin; Peng Shuwen

    2014-01-01

    This paper introduces the transducer structure used double PWM mode, the control system design of hardware and software. The transducer has been applied in factory. From the real experiment, it shows that the system has a high reliability. (authors)

  8. A high-power target experiment

    Kirk, H G; Ludewig, H; Palmer, Robert; Samulyak, V; Simos, N; Tsang, Thomas; Bradshaw, T W; Drumm, Paul V; Edgecock, T R; Ivanyushenkov, Yury; Bennett, Roger; Efthymiopoulos, Ilias; Fabich, Adrian; Haseroth, H; Haug, F; Lettry, Jacques; Hayato, Y; Yoshimura, Koji; Gabriel, Tony A; Graves, Van; Spampinato, P; Haines, John; McDonald, Kirk T

    2005-01-01

    We describe an experiment designed as a proof-of-principle test for a target system capable of converting a 4 MW proton beam into a high-intensity muon beam suitable for incorporation into either a neutrino factory complex or a muon collider. The target system is based on exposing a free mercury jet to an intense proton beam in the presence of a high strength solenoidal field.

  9. Long-pulse applications of pulse-forming lines for high-power linac application

    Hoeberling, R.F.; Tallerico, P.J.

    1981-01-01

    The ever present demands for high efficiency in the RF power stations for particle accelerators have caused increased interest in longer RF pulses (ten's of microseconds) for linacs such as the Pion Generator for Medical Irradiation (PIGMI) and Free Electron Laser (FEL). For either RF power station, a fundamental decision is whether to use a modulating anode/hard-tube driver or pulsed cathode/line-type pulser configuration. The choices in the extremes of low power for very long pulses or for very-high-power, short pulses are, respectively, a modulated anode/hard tube modulator and pulsed cathode/pulse forming line. However, the demarcation between these two extremes is not clearcut. The criteria (cost, flexibility performance, reliability, efficiency) that resulted in the RF station definition of these two specific systems will be described

  10. Stabilized High Power Laser for Advanced Gravitational Wave Detectors

    Willke, B; Danzmann, K; Fallnich, C; Frede, M; Heurs, M; King, P; Kracht, D; Kwee, P; Savage, R; Seifert, F; Wilhelm, R

    2006-01-01

    Second generation gravitational wave detectors require high power lasers with several 100W of output power and with very low temporal and spatial fluctuations. In this paper we discuss possible setups to achieve high laser power and describe a 200W prestabilized laser system (PSL). The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described. Special emphasis will be given to the most demanding power stabilization requirements and new results (RIN ≤ 4x10 -9 /√Hz) will be presented

  11. Power Constrained High-Level Synthesis of Battery Powered Digital Systems

    Nielsen, Sune Fallgaard; Madsen, Jan

    2003-01-01

    We present a high-level synthesis algorithm solving the combined scheduling, allocation and binding problem minimizing area under both latency and maximum power per clock-cycle constraints. Our approach eliminates the large power spikes, resulting in an increased battery lifetime, a property...... of utmost importance for battery powered embedded systems. Our approach extends the partial-clique partitioning algorithm by introducing power awareness through a heuristic algorithm which bounds the design space to those of power feasible schedules. We have applied our algorithm on a set of dataflow graphs...

  12. Experiments on high power EB evaporation of niobium

    Kandaswamy, E.; Bhardwaj, R.L.; Ram Gopal; Ray, A.K.; Kulgod, S.V.

    2002-01-01

    Full text: The versatility of electron beam evaporation makes the deposition of many new and unusual materials possible. This technique offers freedom from contamination and precise control. High power electron guns are especially used for obtaining high evaporation rates for large area coatings. This paper deals with the coating experiments carried out on an indigenously developed high power strip electron gun with niobium as evaporant at 40 kW on S.S. substrate. The practical problems of conditioning the gun and venting the vacuum system after the high power operation are also discussed. The coating rate was calculated by weight difference method

  13. High power industrial picosecond laser from IR to UV

    Saby, Julien; Sangla, Damien; Pierrot, Simonette; Deslandes, Pierre; Salin, François

    2013-02-01

    Many industrial applications such as glass cutting, ceramic micro-machining or photovoltaic processes require high average and high peak power Picosecond pulses. The main limitation for the expansion of the picosecond market is the cost of high power picosecond laser sources, which is due to the complexity of the architecture used for picosecond pulse amplification, and the difficulty to keep an excellent beam quality at high average power. Amplification with fibers is a good technology to achieve high power in picosecond regime but, because of its tight confinement over long distances, light undergoes dramatic non linearities while propagating in fibers. One way to avoid strong non linearities is to increase fiber's mode area. Nineteen missing holes fibers offering core diameter larger than 80μm have been used over the past few years [1-3] but it has been shown that mode instabilities occur at approximately 100W average output power in these fibers [4]. Recently a new fiber design has been introduced, in which HOMs are delocalized from the core to the clad, preventing from HOMs amplification [5]. In these so-called Large Pitch Fibers, threshold for mode instabilities is increased to 294W offering robust single-mode operation below this power level [6]. We have demonstrated a high power-high efficiency industrial picosecond source using single-mode Large Pitch rod-type fibers doped with Ytterbium. Large Pitch Rod type fibers can offer a unique combination of single-mode output with a very large mode area from 40 μm up to 100μm and very high gain. This enables to directly amplify a low power-low energy Mode Locked Fiber laser with a simple amplification architecture, achieving very high power together with singlemode output independent of power level or repetition rate.

  14. Application of parallel connected power-MOSFET elements to high current d.c. power supply

    Matsukawa, Tatsuya; Shioyama, Masanori; Shimada, Katsuhiro; Takaku, Taku; Neumeyer, Charles; Tsuji-Iio, Shunji; Shimada, Ryuichi

    2001-01-01

    The low aspect ratio spherical torus (ST), which has single turn toroidal field coil, requires the extremely high d.c. current like as 20 MA to energize the coil. Considering the ratings of such extremely high current and low voltage, power-MOSFET element is employed as the switching device for the a.c./d.c. converter of power supply. One of the advantages of power-MOSFET element is low on-state resistance, which is to meet the high current and low voltage operation. Recently, the capacity of power-MOSFET element has been increased and its on-state resistance has been decreased, so that the possibility of construction of high current and low voltage a.c./d.c. converter with parallel connected power-MOSFET elements has been growing. With the aim of developing the high current d.c. power supply using power-MOSFET, the basic characteristics of parallel operation with power-MOSFET elements are experimentally investigated. And, the synchronous rectifier type and the bi-directional self commutated type a.c./d.c. converters using parallel connected power-MOSFET elements are proposed

  15. Simulation of Oscillations in High Power Klystrons

    Ko, K

    2003-01-01

    Spurious oscillations can seriously limit a klystron's performance from reaching its design specifications. These are modes with frequencies different from the drive frequency, and have been found to be localized in various regions of the tube. If left unsuppressed, such oscillations can be driven to large amplitudes by the beam. As a result, the main output signal may suffer from amplitude and phase instabilities which lead to pulse shortening or reduction in power generation efficiency, as observed during the testing of the first 150MW S-band klystron, which was designed and built at SLAC as a part of an international collaboration with DESY. We present efficient methods to identify suspicious modes and then test their possibility of oscillation. In difference to [3], where each beam-loaded quality-factor Qbl was calculated by time-consuming PIC simulations, now only tracking-simulations with much reduced cpu-time and less sensitivity against noise are applied. This enables the determination of Qbl for larg...

  16. High cost of nuclear power plants

    Bassett, C.

    1978-01-01

    Retroactive safety standards were found to account for over half the costs of a nuclear power plant and point up the need for an effective cost-benefit analysis of changes made by the Nuclear Regulatory Commission after construction has started. The author compared the Davis-Besse Unit No. 1 construction-cost estimates with the final-cost increases during a rate-case investigation in Ohio. He presents data furnished for ten of the largest construction contracts to illustrate the cost increases involving fixed hardware and intensive labor. The situation was found to repeat with other utilities across the country even though safeguards against irresponsible low bidding were introduced. Low bidding was found to continue, encouraged by the need for retrofitting to meet regulation changes. The average cost per kilowatt of major light-water reactors is shown to have increased from $171 in 1970 to $555 in 1977, while construction duration increased from 43.4 to 95.6 months during the same period

  17. High Power Proton Beam Shocks and Magnetohydrodynamics in a Mercury Jet Target for a Neutrino Factory

    Fabich, A; Fabjan, Christian

    2002-01-01

    The feasibility of liquid metal jet targets for secondary particle production with high power proton beams has been studied. The main aspects of the thesis were benchmark experiments covering the behaviour of liquid targets under thermal shock waves induced by high power proton beams, and also magnetohydrodynamic effects. Severe challenges were imposed by safety issues and the restricted beam time to the tests in ISOLDE at CERN and at the High Magnetic Field Laboratory at Grenoble. Restricted access times in high radiation level areas were of the order of minutes and in this short time span, the complete experimental setup had to be performed and verified. The involvement of mercury as liquid target material and its activation during beam tests demanded special confinement precautions. The setup for both experiments was based on the use of a high speed camera system for observation of the mercury target. The presence of high radiation or high magnetic field required the installation of the sensitive camera sy...

  18. Numerical simulations of novel high-power high-brightness diode laser structures

    Boucke, Konstantin; Rogg, Joseph; Kelemen, Marc T.; Poprawe, Reinhart; Weimann, Guenter

    2001-07-01

    One of the key topics in today's semiconductor laser development activities is to increase the brightness of high-power diode lasers. Although structures showing an increased brightness have been developed specific draw-backs of these structures lead to a still strong demand for investigation of alternative concepts. Especially for the investigation of basically novel structures easy-to-use and fast simulation tools are essential to avoid unnecessary, cost and time consuming experiments. A diode laser simulation tool based on finite difference representations of the Helmholtz equation in 'wide-angle' approximation and the carrier diffusion equation has been developed. An optimized numerical algorithm leads to short execution times of a few seconds per resonator round-trip on a standard PC. After each round-trip characteristics like optical output power, beam profile and beam parameters are calculated. A graphical user interface allows online monitoring of the simulation results. The simulation tool is used to investigate a novel high-power, high-brightness diode laser structure, the so-called 'Z-Structure'. In this structure an increased brightness is achieved by reducing the divergency angle of the beam by angular filtering: The round trip path of the beam is two times folded using internal total reflection at surfaces defined by a small index step in the semiconductor material, forming a stretched 'Z'. The sharp decrease of the reflectivity for angles of incidence above the angle of total reflection leads to a narrowing of the angular spectrum of the beam. The simulations of the 'Z-Structure' indicate an increase of the beam quality by a factor of five to ten compared to standard broad-area lasers.

  19. High power and high energy electrodes using carbon nanotubes

    Martini, Fabrizio; Brambilla, Nicolo Michele; Signorelli, Riccardo

    2015-04-07

    An electrode useful in an energy storage system, such as a capacitor, includes an electrode that includes at least one to a plurality of layers of compressed carbon nanotube aggregate. Methods of fabrication are provided. The resulting electrode exhibits superior electrical performance in terms of gravimetric and volumetric power density.

  20. Seismic Performance of High-Ductile Fiber-Reinforced Concrete Short Columns

    Mingke Deng

    2018-01-01

    Full Text Available This study mainly aims to investigate the effectiveness of high-ductile fiber-reinforced concrete (HDC as a means to enhance the seismic performance of short columns. Six HDC short columns and one reinforced concrete (RC short column were designed and tested under lateral cyclic loading. The influence of the material type (concrete or HDC, axial load, stirrup ratio, and shear span ratio on crack patterns, hysteresis behavior, shear strength, deformation capacity, energy dissipation, and stiffness degradation was presented and discussed, respectively. The test results show that the RC short column failed in brittle shear with poor energy dissipation, while using HDC to replace concrete can effectively improve the seismic behavior of the short columns. Compared with the RC short column, the shear strength of HDC specimens was improved by 12.6–30.2%, and the drift ratio and the energy dissipation increases were 56.9–88.5% and 237.7–336.7%, respectively, at the ultimate displacement. Additionally, the prediction model of the shear strength for RC columns based on GB50010-2010 (Chinese code can be safely adopted to evaluate the shear strength of HDC short columns.

  1. Deterministic and probabilistic interval prediction for short-term wind power generation based on variational mode decomposition and machine learning methods

    Zhang, Yachao; Liu, Kaipei; Qin, Liang; An, Xueli

    2016-01-01

    Highlights: • Variational mode decomposition is adopted to process original wind power series. • A novel combined model based on machine learning methods is established. • An improved differential evolution algorithm is proposed for weight adjustment. • Probabilistic interval prediction is performed by quantile regression averaging. - Abstract: Due to the increasingly significant energy crisis nowadays, the exploitation and utilization of new clean energy gains more and more attention. As an important category of renewable energy, wind power generation has become the most rapidly growing renewable energy in China. However, the intermittency and volatility of wind power has restricted the large-scale integration of wind turbines into power systems. High-precision wind power forecasting is an effective measure to alleviate the negative influence of wind power generation on the power systems. In this paper, a novel combined model is proposed to improve the prediction performance for the short-term wind power forecasting. Variational mode decomposition is firstly adopted to handle the instability of the raw wind power series, and the subseries can be reconstructed by measuring sample entropy of the decomposed modes. Then the base models can be established for each subseries respectively. On this basis, the combined model is developed based on the optimal virtual prediction scheme, the weight matrix of which is dynamically adjusted by a self-adaptive multi-strategy differential evolution algorithm. Besides, a probabilistic interval prediction model based on quantile regression averaging and variational mode decomposition-based hybrid models is presented to quantify the potential risks of the wind power series. The simulation results indicate that: (1) the normalized mean absolute errors of the proposed combined model from one-step to three-step forecasting are 4.34%, 6.49% and 7.76%, respectively, which are much lower than those of the base models and the hybrid

  2. Surface processing by high power excimer laser

    Stehle, M [SOPRA, 92 - Bois-Colombes (France)

    1995-03-01

    Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at {lambda} = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : (a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. (b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. (c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. (d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.).

  3. Surface processing by high power excimer laser

    Stehle, M.

    1995-01-01

    Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at λ = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.)

  4. Analysis of chaos in high-dimensional wind power system.

    Wang, Cong; Zhang, Hongli; Fan, Wenhui; Ma, Ping

    2018-01-01

    A comprehensive analysis on the chaos of a high-dimensional wind power system is performed in this study. A high-dimensional wind power system is more complex than most power systems. An 11-dimensional wind power system proposed by Huang, which has not been analyzed in previous studies, is investigated. When the systems are affected by external disturbances including single parameter and periodic disturbance, or its parameters changed, chaotic dynamics of the wind power system is analyzed and chaotic parameters ranges are obtained. Chaos existence is confirmed by calculation and analysis of all state variables' Lyapunov exponents and the state variable sequence diagram. Theoretical analysis and numerical simulations show that the wind power system chaos will occur when parameter variations and external disturbances change to a certain degree.

  5. A short-term spatio-temporal approach for Photovoltaic power forecasting

    Tascikaraoglu, A.; Sanandaji, B.M.; Chicco, G.; Cocina, V.; Spertino, F.; Erdinc, Ozan; Paterakis, N.G.; Catalão, J.P.S.

    2016-01-01

    This paper presents a Photovoltaic (PV) power conversion model and a forecasting approach which uses spatial dependency of variables along with their temporal information. The power produced by a PV plant is forecasted by a PV conversion model using the predictions of three weather variables,

  6. Design of measurement equipment for high power laser beam shapes

    Hansen, K. S.; Olsen, F. O.; Kristiansen, Morten

    2013-01-01

    To analyse advanced high power beam patterns, a method, which is capable of analysing the intensity distribution in 3D is needed. Further a measuring of scattered light in the same system is preferred. This requires a high signal to noise ratio. Such a system can be realised by a CCD-chip impleme...... by a commercial product has been done. The realised system might suffer from some thermal drift at high power; future work is to clarify this....

  7. Modular high voltage power supply for chemical analysis

    Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

    2008-07-15

    A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

  8. Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players.

    Yáñez-Silva, Aquiles; Buzzachera, Cosme F; Piçarro, Ivan Da C; Januario, Renata S B; Ferreira, Luis H B; McAnulty, Steven R; Utter, Alan C; Souza-Junior, Tacito P

    2017-01-01

    To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d -1 during 14 d) on muscle power output in elite youth soccer players. Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr ( N  = 9) or placebo ( N  = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. There were significant increases in both PPO and MPO after the Cr supplementation period ( P  ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods ( P  ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after ( P  ≤ 0.05) but not before the 14 d supplementation period. There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.

  9. Development of High Temperature Short Time Vertebrate-Blood Pasteurization Equipment for Tsetse Fly Diets

    Moravek, I; Lach, J [Department of Manufacturing Systems, Slovak Technical University Namestie Slobody 17 812 31 Bratislava (Slovakia); Takac, P [Institute of Zoology, SAV, Bratislava (Slovakia)

    2012-07-15

    Tsetse flies feed only on vertebrate blood, but the collection and processing of blood is expensive, it must be stored at -20{sup o}C requiring costly storage rooms and reliable electricity, and it must be irradiated to reduce bacterial contamination. This is tolerable for small colonies, but as colony size increases to service large- scale programmes, the supply and processing of blood becomes critical. Blood is normally collected from cattle at slaughter. This process is necessarily not aseptic, and large-scale collection is only possible where the animals are suspended for bleeding. One alternative to blood decontamination is using the High Temperature Short time Pasteurization (HTST) method. The food processing industry uses pasteurization to reduce bacterial load in a wide range of products. Our previous results indicated that for the control of the blood pasteurization process, to reach satisfactory bacteriological purity and at the same time to prevent the blood from coagulating, it is important to study temperature and time and also some other parameters that could predict blood coagulation. Crucial for blood coagulation is to study blood viscosity. Classical heat exchangers are not suitable for blood pasteurization. In such equipment the blood coagulation depends on temperature and time. Besides the relatively low temperatures, blood is coagulating with cumulative time until total shutdown of blood flow. After a series of experiments we found a solution using microwave systems. To verify the microwave heating concept, we built an experimental workstation. First we verified the accuracy of the applicator design from the aspect of output adaptation to the power source. Also we installed measuring equipment. This system complies with the requirements of quick heating with sufficiently high heat accumulation. By utilizing standard components for the base of the microwave generator, it is possible to markedly reduce the final price of the equipment. (author)

  10. Cryogenic cooling for high power laser amplifiers

    Perin J.P.

    2013-11-01

    Full Text Available Using DPSSL (Diode Pumped Solid State Lasers as pumping technology, PW-class lasers with enhanced repetition rates are developed. Each of the Yb YAG amplifiers will be diode-pumped at a wavelength of 940 nm. This is a prerequisite for achieving high repetition rates (light amplification duration 1 millisecond and repetition rate 10 Hz. The efficiency of DPSSL is inversely proportional to the temperature, for this reason the slab amplifier have to be cooled at a temperature in the range of 100 K–170 K with a heat flux of 1 MW*m−2. This paper describes the thermo-mechanical analysis for the design of the amplification laser head, presents a preliminary proposal for the required cryogenic cooling system and finally outlines the gain of cryogenic operation for the efficiency of high pulsed laser.

  11. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  12. Pulsed Power Applications in High Intensity Proton Rings

    Zhang, Wu; Ducimetière, Laurent; Fowler, Tony; Kawakubo, Tadamichi; Mertens, Volker; Sandberg, Jon; Shirakabe, Yoshihisa

    2005-01-01

    The pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.

  13. ACIGA's high optical power test facility

    Ju, L [School of Physics, University of Western Australia, Perth (Australia); Aoun, M [Computer and Information Science, Edith Cowan University, Perth (Australia); Barriga, P [School of Physics, University of Western Australia, Perth (Australia)] [and others

    2004-03-07

    Advanced laser interferometer detectors utilizing more than 100 W of laser power and with {approx}10{sup 6} W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties.

  14. Technical and economic considerations of extra high voltage power transmission

    Kahnt, R

    1966-09-01

    The reasons for the employment of higher transmission voltages are listed and the points decisive for the selection of three phase ac or dc systems are reviewed. This is followed by treatment of the technical and economic problems arising in three phase-extra high voltage transmission. These include selection of voltage, economical design of power lines, insulation problems, power supply dependability, equipment rating, and reactive power and stability problems.

  15. Technical and economic considerations of extra high voltage power transmission

    Kahnt, R

    1966-09-01

    The reasons for the employment of higher transmission voltages are listed and the points decisive for the selection of three phase ac or dc systems are reviewed. The technical and economic problems arising in three phase extra high voltage transmission are discussed. These include selection of voltage, economical design of power lines, insulation problems, power supply dependability, equipment rating and reactive power and stability problems.

  16. High frequency modeling of power transformers. Stresses and diagnostics

    Bjerkan, Eilert

    2005-05-15

    In this thesis a reliable, versatile and rigorous method for high frequency power transformer modeling is searched and established. The purpose is to apply this model to sensitivity analysis of FRA (Frequency Response Analysis) which is a quite new diagnostic method for assessing the mechanical integrity of power transformer windings on-site. The method should be versatile in terms of being able to estimate internal and external over voltages and resonances. Another important aspect is that the method chosen is suitable for real transformer geometries. In order to verify the suitability of the model for real transformers, a specific test-object is used. This is a 20MVA transformer, and details are given in chapter 1.4. The high frequency power transformer model is established from geometrical and constructional information from the manufacturer, together with available material characteristics. All circuit parameters in the lumped circuit representation are calculated based on these data. No empirical modifications need to be performed. Comparison shows capability of reasonable accuracy in the range from 10 khz to 1 MHz utilizing a disc-to-disc representation. A compromise between accuracy of model due to discretization and complexity of the model in a turn-to-turn representation is inevitable. The importance of the iron core is emphasized through a comparison of representations with/without the core included. Frequency-dependent phenomena are accurately represented using an isotropic equivalent for windings and core, even with a coarse mesh for the FEM-model. This is achieved through a frequency-dependent complex permeability representation of the materials. This permeability is deduced from an analytical solution of the frequency-dependent magnetic field inside the conductors and the core. The importance of dielectric losses in a transformer model is also assessed. Since published data on the high frequency properties of press board are limited, some initial

  17. High-power generator of singlet oxygen

    Jirásek, Vít; Čenský, Miroslav; Špalek, Otomar; Kodymová, Jarmila

    2013-01-01

    Roč. 36, č. 10 (2013), s. 1755-1763 ISSN 0930-7516 Grant - others:Laser Science and Technology Centre(IN) LASTEC/FE/RKT/54/10-11 Institutional research plan: CEZ:AV0Z10100523 Keywords : high-pressure singlet oxygen generator * spray generator * centrifugal separation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.175, year: 2013

  18. The power processor of a high temperature superconducting energy storage system

    Ollila, J. [Power Electronics, Tampere University of Technology, Tampere (Finland)

    1997-12-31

    This report introduces the structure and properties of a power processor unit for a high temperature superconducting magnetic energy storage system which is bused in an UPS demonstration application. The operation is first demonstrated using simulations. The software based operating and control system utilising combined Delta-Sigma and Sliding-Mode control is described shortly. Preliminary test results using a conventional NbTi superconducting energy y storage magnet operating at 4.2 K is shown. (orig.)

  19. Mechanical properties of concrete for power reactor at high temperatures

    Kawase, Kiyotaka; Tanaka, Hitoshi; Nakano, Masayuki

    1985-01-01

    The purpose of this study is to investigate the mechanical properties of concrete for power reactor at high temperature. This paper presents the creep behavior of concrete at high temperature and the cause by which a specified aggregate is broken at a specified high temperature. The creep coefficient at high temperature is smaller than that at ordinary temperature. (author)

  20. Topologically protected loop flows in high voltage AC power grids

    Coletta, T; Delabays, R; Jacquod, Ph; Adagideli, I

    2016-01-01

    Geographical features such as mountain ranges or big lakes and inland seas often result in large closed loops in high voltage AC power grids. Sizable circulating power flows have been recorded around such loops, which take up transmission line capacity and dissipate but do not deliver electric power. Power flows in high voltage AC transmission grids are dominantly governed by voltage angle differences between connected buses, much in the same way as Josephson currents depend on phase differences between tunnel-coupled superconductors. From this previously overlooked similarity we argue here that circulating power flows in AC power grids are analogous to supercurrents flowing in superconducting rings and in rings of Josephson junctions. We investigate how circulating power flows can be created and how they behave in the presence of ohmic dissipation. We show how changing operating conditions may generate them, how significantly more power is ohmically dissipated in their presence and how they are topologically protected, even in the presence of dissipation, so that they persist when operating conditions are returned to their original values. We identify three mechanisms for creating circulating power flows, (i) by loss of stability of the equilibrium state carrying no circulating loop flow, (ii) by tripping of a line traversing a large loop in the network and (iii) by reclosing a loop that tripped or was open earlier. Because voltages are uniquely defined, circulating power flows can take on only discrete values, much in the same way as circulation around vortices is quantized in superfluids. (paper)

  1. Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator

    Song, Xiaowei (Andy); Liu, Dong; Polinder, Henk

    2016-01-01

    Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen...... at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator’s equivalent circuits is developed to simulate short circuit faults. Afterwards, the model is used to study the transient performance of a 10 MW HTS wind turbine generator under four different short...... that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The results presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator....

  2. Dynamic Modeling and Very Short-term Prediction of Wind Power Output Using Box-Cox Transformation

    Urata, Kengo; Inoue, Masaki; Murayama, Dai; Adachi, Shuichi

    2016-09-01

    We propose a statistical modeling method of wind power output for very short-term prediction. The modeling method with a nonlinear model has cascade structure composed of two parts. One is a linear dynamic part that is driven by a Gaussian white noise and described by an autoregressive model. The other is a nonlinear static part that is driven by the output of the linear part. This nonlinear part is designed for output distribution matching: we shape the distribution of the model output to match with that of the wind power output. The constructed model is utilized for one-step ahead prediction of the wind power output. Furthermore, we study the relation between the prediction accuracy and the prediction horizon.

  3. A battery-powered high-current power supply for superconductors

    Wake, M; Suda, K

    2002-01-01

    Since superconductors do not require voltages, a high-current power supply could run with low power if the voltage is sufficiently reduced. Even a battery-powered power supply could give as much as 2,000A for a superconductor. To demonstrate this hypothesis, a battery-powered 2,000A power supply was constructed. It uses an IGBT chopper and Schottky diode together with a specially arranged transformer to produce a high current with low voltage. Testing of 2,000A operation was performed for about 1.5 hr using 10 car batteries. Charging time for this operation was 8 hr. Ramping control was smooth and caused no trouble. Although the IGBT frequency ripple of 16.6 kHz was easily removed using a passive filter, spike noise remained in the output voltage. This ripple did not cause any trouble in operating a pancake-type inductive superconducting load. (author)

  4. High-Power Electron Accelerators for Space (and other) Applications

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-23

    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  5. Design methods for high temperature power plant structures

    Townley, C.H.A.

    1984-01-01

    The subject is discussed under the headings: introduction (scope of paper - reviews of design methods and design criteria currently in use for both nuclear and fossil fuelled power plant; examples chosen are (a) BS 1113, representative of design codes employed for power station boiler plant; (b) ASME Code Case N47, which is being developed for high temperature nuclear reactors, especially the liquid metal fast breeder reactor); design codes for power station boilers; Code Case N47 (design in the absence of thermal shock and thermal fatigue; design against cyclic loading at high temperature; further research in support of high temperature design methods and criteria for LMFBRs); concluding remarks. (U.K.)

  6. High performance protection circuit for power electronics applications

    Tudoran, Cristian D., E-mail: cristian.tudoran@itim-cj.ro; Dădârlat, Dorin N.; Toşa, Nicoleta; Mişan, Ioan [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, PO 5 Box 700, 400293 Cluj-Napoca (Romania)

    2015-12-23

    In this paper we present a high performance protection circuit designed for the power electronics applications where the load currents can increase rapidly and exceed the maximum allowed values, like in the case of high frequency induction heating inverters or high frequency plasma generators. The protection circuit is based on a microcontroller and can be adapted for use on single-phase or three-phase power systems. Its versatility comes from the fact that the circuit can communicate with the protected system, having the role of a “sensor” or it can interrupt the power supply for protection, in this case functioning as an external, independent protection circuit.

  7. Short-term strategies for Dutch wind power producers to reduce imbalance costs

    Chaves-Ávila, José Pablo; Hakvoort, Rudi A.; Ramos, Andrés

    2013-01-01

    The paper assesses bidding strategies for a wind power producer in the Netherlands. To this end, a three-stage stochastic optimization framework is used, maximizing wind power producer's profit using the day-ahead and cross-border intraday market, taking into account available interconnection capacity. Results show that the wind power producer can increase its profits by trading on the intraday market and – under certain imbalance prices – by intentionally creating imbalances. It has been considered uncertainties about prices, power forecast and interconnection capacity at the day-ahead and intraday timeframes. - Highlights: ► A cross-border bidding strategy model for wind power producers has been developed. ► The model was applied to a real case study of a Dutch offshore wind power producer. ► Under certain imbalance prices, it is not profitable to deliver all possible power. ► Intraday markets give the possibility to reduce imbalance costs. ► Integration of intraday markets will increase liquidity.

  8. High power density reactors based on direct cooled particle beds

    Powell, J. R.; Horn, F. L.

    Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

  9. New window materials for high power gyrotron

    Afsar, M.N.; Hua Chi

    1993-01-01

    A single free standing synthetic diamond window seems to have higher absorption coefficient value at millimeter wavelength region at this time although it is claimed that it possesses good mechanical strength and higher thermal conductivity characteristics. It certainly does not rule out the use of diamond film on single crystal high resistivity silicon to improve its mechanical strength and thermal conductivity. One may have to use an appropriate film thickness for a particular wavelength in gyrotron window application. It is also necessary to use an appropriate thickness for the silicon perhaps equivalent to a quaterwavelength in order to avoid the reflection mismatch

  10. Entropy method combined with extreme learning machine method for the short-term photovoltaic power generation forecasting

    Tang, Pingzhou; Chen, Di; Hou, Yushuo

    2016-01-01

    As the world’s energy problem becomes more severe day by day, photovoltaic power generation has opened a new door for us with no doubt. It will provide an effective solution for this severe energy problem and meet human’s needs for energy if we can apply photovoltaic power generation in real life, Similar to wind power generation, photovoltaic power generation is uncertain. Therefore, the forecast of photovoltaic power generation is very crucial. In this paper, entropy method and extreme learning machine (ELM) method were combined to forecast a short-term photovoltaic power generation. First, entropy method is used to process initial data, train the network through the data after unification, and then forecast electricity generation. Finally, the data results obtained through the entropy method with ELM were compared with that generated through generalized regression neural network (GRNN) and radial basis function neural network (RBF) method. We found that entropy method combining with ELM method possesses higher accuracy and the calculation is faster.

  11. Wind Power Forecasting Based on Echo State Networks and Long Short-Term Memory

    López, Erick; Allende, Héctor; Gil, Esteban

    2018-01-01

    involved. In particular, two types of RNN, Long Short-Term Memory (LSTM) and Echo State Network (ESN), have shown good results in time series forecasting. In this work, we present an LSTM+ESN architecture that combines the characteristics of both networks. An architecture similar to an ESN is proposed...

  12. EQUATIONS OF ELECTRIC MOTOR POWER SUPPLY UNIT DISSYMMETRY UNDER PHASE SHORT-CIRCUIT FAULT

    V.Y. Tchaban

    2013-04-01

    Full Text Available In the paper, a formula is introduced for calculating electric motor supply unit voltage under feeding by a common transformer in the condition of a phase short-circuit in one of the motors. The formula is used in every time step of electromechanical state equations integration.

  13. Electric Vehicles for Improved Operation of Power Systems with High Wind Power Penetration

    Larsen, Esben; Chandrashekhara, Divya K; Østergaard, Jacob

    2008-01-01

    In a power system with a high share of wind energy the wind fluctuation causes a variation in the power generation, which must be compensated from other sources. The situation in Denmark with a penetration of more than 20% wind in yearly average is presented. The introduction of electric drive vehicles (EDV) as flexible loads can improve the system operation. Bidirectional power exchange through batteries (vehicle to grid) can be seen as a storage system in the grid. An analysis of possible e...

  14. Measurement of soft X-ray power from high-power Z-pinch plasma

    Wang Wensheng; Qiu Aici; Sun Fengrong; Luo Jianhui; Zhou Haisheng; He Duohui

    2003-01-01

    A Ni-film bolometer driven by the pulsed constant-voltage supply was developed for measuring soft X-ray energy under 1 keV generated from the Qiang-Guang-I, while the measuring system of the soft X-ray power was established with an X-ray diode detector. Results of the soft X-ray energy and power measurements were obtained at the experiment of Kr gas-puff high-power Z-pinch plasma

  15. Intense neutron source: high-voltage power supply specifications

    Riedel, A.A.

    1980-08-01

    This report explains the need for and sets forth the electrical, mechanical and safety specifications for a high-voltage power supply to be used with the intense neutron source. It contains sufficient information for a supplier to bid on such a power supply

  16. High Power RF Transmitters for ICRF Applications on EAST

    Mao Yuzhou; Yuan Shuai; Zhao Yanping; Zhang Xinjun; Chen Gen; Cheng Yan; Wang Lei; Ju Songqing; Deng Xu; Qin Chengming; Yang Lei; Kumazawa, R.

    2013-01-01

    An Ion Cyclotron Range of Frequency (ICRF) system with a radio frequency (RF) power of 4 × 1.5 MW was developed for the Experimental Advanced Superconducting Tokamak (EAST). High RF power transmitters were designed as a part of the research and development (R and D) for an ICRF system with long pulse operation at megawatt levels in a frequency range of 25 MHz to 70 MHz. Studies presented in this paper cover the following parts of the high power transmitter: the three staged high power amplifier, which is composed of a 5 kW wideband solid state amplifier, a 100 kW tetrode drive stage amplifier and a 1.5 MW tetrode final stage amplifier, and the DC high voltage power supply (HVPS). Based on engineering design and static examinations, the RF transmitters were tested using a matched dummy load where an RF output power of 1.5 MW was achieved. The transmitters provide 6 MW RF power in primary phase and will reach a level up to 12 MW after a later upgrade. The transmitters performed successfully in stable operations in EAST and HT-7 devices. Up to 1.8 MW of RF power was injected into plasmas in EAST ICRF heating experiments during the 2010 autumn campaign and plasma performance was greatly improved.

  17. Efficient and high-power green beam generation by frequency ...

    Rz; 42.60.Gd. 1. Introduction. High-average-power green lasers are required for various applications in industry, ... mode size, however, vary dynamically with the pump power due to thermal lensing in the Nd:YAG rod. ... fundamental mode size at the Nd:YAG rod as well as at the KTP crystal is plotted as a function of the ...

  18. Secondary hazards of high power laser beam welding

    Schulmeister, K.; Schmitzer, C.; Duftschmid, K.; Liedl, G.; Schroeder, K.; Schuoecker, D.

    1996-01-01

    Hazardous UV-radiation and short-wavelength visible (blue) light is emitted by the high temperature plasma above the welding-keyhole. Ozone and NO x is produced due to UV-induced photodissociation of oxygen and high temperature gas-phase reactions. Spectral measurements of the plasma emission show that the allowed dose for UV-radiation and blue light exposure per work day can be exceeded in as short as a few seconds. Similarly, measurements and models of the ozone and NO x concentration show that the maximum workplace concentrations might be reached quickly if no appropriate exhaust and filter system is installed. (author)

  19. HIGH RESOLUTION ANALOG / DIGITAL POWER SUPPLY CONTROLLER

    Medvedko, Evgeny A

    2003-01-01

    Corrector magnets for the SPEAR-3 synchrotron radiation source require precision, high-speed control for use with beam-based orbit feedback. A new Controller Analog/Digital Interface card (CANDI) has been developed for these purposes. The CANDI has a 24-bit DAC for current control and three 24-bit Δ-Σ ADCs to monitor current and voltages. The ADCs can be read and the DAC updated at the 4 kHz rate needed for feedback control. A precision 16-bit DAC provides on-board calibration. Programmable multiplexers control internal signal routing for calibration, testing, and measurement. Feedback can be closed internally on current setpoint, externally on supply current, or beam position. Prototype and production tests are reported in this paper. Noise is better than 17 effective bits in a 10 mHz to 2 kHz bandwidth. Linearity and temperature stability are excellent

  20. Design of high power feedthrough for High Power Industrial Accelerator (HPIA)

    Soni, Rakesh Kumar; Kumar, Abhay; Dwivedi, Jishnu; Kumar, Pankaj; Goswami, S.G.

    2011-01-01

    This paper reports the design, assembly and dismantling and maintenance of a feedthrough for High Power Industrial Accelerator (HPIA). It has been designed to serve three purposes. It provides electrical insulation between primary windings (at ∼ 2.5 kV) and cover flange (at ground potential) with the help of Nylon bushes. It also ensures leak tightness for SF 6 gas filled inside the vessel at 10 bar. It also provides sealing for water connectors between the primary winding and secondary winding. The key function of this feedthrough is to supply ∼ 800 A of current to the primary circuit. Technical requirement/constraint is leak tightness and electrical isolation of feedthrough. This feedthrough will be connected to the primary windings inside the vessel. Current will flow through a copper tube conductor which is at a potential of ∼ 800 V. Inside the tube water is flowing. Inlet water temperature is ∼ 30℃. Flow rate of water is 35 litres/minute at 6 kg/cm 2 pressure to remove the heat losses. (author)