WorldWideScience

Sample records for voltage high temperature

  1. Temperature Stabilized Characterization of High Voltage Power Supplies

    CERN Document Server

    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.

  2. Temperature and Voltage Offsets in High-ZT Thermoelectrics

    Science.gov (United States)

    Levy, George S.

    2017-10-01

    Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high-ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/n + and p/p + junctions, selecting appropriate dimensions, doping, and loading.

  3. Temperature and Voltage Offsets in High- ZT Thermoelectrics

    Science.gov (United States)

    Levy, George S.

    2018-06-01

    Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high- ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/ n + and p/ p + junctions, selecting appropriate dimensions, doping, and loading.

  4. Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

    Science.gov (United States)

    Yunxiao, ZHANG; Yuanxiang, ZHOU; Ling, ZHANG; Zhen, LIN; Jie, LIU; Zhongliu, ZHOU

    2018-05-01

    In this paper, work was conducted to reveal electrical tree behaviors (initiation and propagation) of silicone rubber (SIR) under an impulse voltage with high temperature. Impulse frequencies ranging from 10 Hz to 1 kHz were applied and the temperature was controlled between 30 °C and 90 °C. Experimental results show that tree initiation voltage decreases with increasing pulse frequency, and the descending amplitude is different in different frequency bands. As the pulse frequency increases, more frequent partial discharges occur in the channel, increasing the tree growth rate and the final shape intensity. As for temperature, the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher. Based on differential scanning calorimetry results, we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage. However, the tree growth rate decreases with increasing temperature. Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis. Different tree growth models considering tree channel characteristics are proposed. It is believed that increasing the conductivity in the tree channel restrains the partial discharge, holding back the tree growth at high temperature.

  5. Improvements on high voltage capacity and high temperature performances of Si-based Schottky potential barrier diode

    International Nuclear Information System (INIS)

    Wang Yongshun; Rui Li; Adnan Ghaffar; Wang Zaixing; Liu Chunjuan

    2015-01-01

    In order to improve the reverse voltage capacity and low junction temperature characteristics of the traditional silicon-based Schottky diode, a Schottky diode with high reverse voltage capacity and high junction temperature was fabricated using ion implantation, NiPt60 sputtering, silicide-forming and other major technologies on an N-type silicon epitaxial layer of 10.6–11.4 μm and (2.2–2.4) × 10 15 cm −3 doping concentration. The measurement results show that the junction temperature of the Schottky diode fabricated can reach 175 °C, that is 50 °C higher than that of the traditional one; the reverse voltage capacity V R can reach 112 V, that is 80 V higher than that of the traditional one; the leakage current is only 2 μA and the forward conduction voltage drop is V F = 0.71 V at forward current I F = 3 A. (semiconductor devices)

  6. Experimental investigation of high temperature high voltage thermionic diode for the space power nuclear reactor

    International Nuclear Information System (INIS)

    Onufriyev, Valery V.

    2001-01-01

    It is well known that the rise of arc from the dense glow discharge is connected with the thermion and secondary processes on the cathode surface (Granovsky, 1971; Leob, 1953; Engel, 1935). First model of breakdown of the cathode layer is connected with the increase of the cathode temperature in consequence of the ion bombardment that leads to the grows its thermo-emissive current. Other model shows the main role of the secondary effects on the cathode surface-the increase of the secondary ion emission coefficient--γ i with the grows of glow discharge voltage. But the author of this investigation work of breakdown in Cs vapor (a transmission the glow discharge into self-maintaining arc discharge) discovered the next peculiarity: the value of breakdown voltage is constant when the values of vapor temperature (its pressure p cs ) and cathode temperature T k is constant too (U b =constant with T k =constant and p cs =constant) and it is not a statistical value (Onufryev, Grishin, 1996) (that was observed in gas glow discharges other authors (Granovsky, 1971; Leob, 1953; Engel, 1935)). The investigations of thermion high voltage high temperature diode (its breakdown characteristics in closed state and voltage-current characteristics in disclosed state) showed that the value of the breakdown voltage is depended on the vapor pressure in inter-electrode gap (IEG)-p cs and cathode temperature-T k and is independent on IEG length--Δ ieg . On this base it was settled that the main role in transition of glow discharge to self-maintaining arc discharge plays an ion cathode layer but more exactly--the region of excited atoms--''Aston glow.''

  7. Experimental investigation of high temperature high voltage thermionic diode for the space power nuclear reactor

    Science.gov (United States)

    Onufriyev, Valery. V.

    2001-02-01

    It is well known that the rise of arc from the dense glow discharge is connected with the thermion and secondary processes on the cathode surface (Granovsky, 1971; Leob, 1953; Engel, 1935). First model of breakdown of the cathode layer is connected with the increase of the cathode temperature in consequence of the ion bombardment that leads to the grows its thermo-emissive current. Other model shows the main role of the secondary effects on the cathode surface-the increase of the secondary ion emission coefficient-γi with the grows of glow discharge voltage. But the author of this investigation work of breakdown in Cs vapor (a transmission the glow discharge into self-maintaining arc discharge) discovered the next peculiarity: the value of breakdown voltage is constant when the values of vapor temperature (its pressure pcs) and cathode temperature Tk is constant too (Ub=constant with Tk=constant and pcs=constant) and it is not a statistical value (Onufryev, Grishin, 1996) (that was observed in gas glow discharges other authors (Granovsky, 1971; Leob, 1953; Engel, 1935)). The investigations of thermion high voltage high temperature diode (its breakdown characteristics in closed state and voltage-current characteristics in disclosed state) showed that the value of the breakdown voltage is depended on the vapor pressure in inter-electrode gap (IEG)-pcs and cathode temperature-Tk and is independent on IEG length-Δieg. On this base it was settled that the main role in transition of glow discharge to self-maintaining arc discharge plays an ion cathode layer but more exactly-the region of excited atoms-``Aston glow.'' .

  8. Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

    Energy Technology Data Exchange (ETDEWEB)

    Erofeev, E. V., E-mail: erofeev@micran.ru [Tomsk State University of Control Systems and Radioelectronics, Research Institute of Electrical-Communication Systems (Russian Federation); Fedin, I. V.; Kutkov, I. V. [Research and Production Company “Micran” (Russian Federation); Yuryev, Yu. N. [National Research Tomsk Polytechnic University, Institute of Physics and Technology (Russian Federation)

    2017-02-15

    High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping level makes it possible to attain a threshold voltage of GaN transistors close to V{sub th} = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V{sub th} = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.

  9. Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

    International Nuclear Information System (INIS)

    Erofeev, E. V.; Fedin, I. V.; Kutkov, I. V.; Yuryev, Yu. N.

    2017-01-01

    High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping level makes it possible to attain a threshold voltage of GaN transistors close to V_t_h = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V_t_h = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.

  10. Ultra-low power high temperature and radiation hard complementary metal-oxide-semiconductor (CMOS) silicon-on-insulator (SOI) voltage reference.

    Science.gov (United States)

    Boufouss, El Hafed; Francis, Laurent A; Kilchytska, Valeriya; Gérard, Pierre; Simon, Pascal; Flandre, Denis

    2013-12-13

    This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40-200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si) performed at three different temperatures (room temperature, 100 °C and 200 °C). The maximum drift of the reference voltage V(REF) depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 μW at room temperature and only 75 μW at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of V(REF) and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2.

  11. Current-voltage-temperature characteristics of DNA origami

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M [Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States); Zhong Hong; Norton, Michael L [Department of Chemistry, Marshall University, Huntington, WV 25755 (United States); Sinitskii, Alexander [Department of Chemistry, Rice University, Houston, TX 77005 (United States)

    2009-04-29

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of {approx}0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  12. Current-voltage-temperature characteristics of DNA origami

    International Nuclear Information System (INIS)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M; Zhong Hong; Norton, Michael L; Sinitskii, Alexander

    2009-01-01

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of ∼0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  13. High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-02-14

    We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

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

    Science.gov (United States)

    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.

  15. Current-voltage characteristics of C70 solid near Meyer-Neldel temperature

    Science.gov (United States)

    Onishi, Koichi; Sezaimaru, Kouki; Nakashima, Fumihiro; Sun, Yong; Kirimoto, Kenta; Sakaino, Masamichi; Kanemitsu, Shigeru

    2017-06-01

    The current-voltage characteristics of the C70 solid with hexagonal closed-packed structures were measured in the temperature range of 250-450 K. The current-voltage characteristics can be described as a temporary expedient by a cubic polynomial of the voltage, i = a v 3 + b v 2 + c v + d . Moreover, the Meyer-Neldel temperature of the C70 solid was confirmed to be 310 K, at which a linear relationship between the current and voltage was observed. Also, at temperatures below the Meyer-Neldel temperature, the current increases with increasing voltage. On the other hand, at temperatures above the Meyer-Neldel temperature a negative differential conductivity effect was observed at high voltage side. The negative differential conductivity was related to the electric field and temperature effects on the mobility of charge carrier, which involve two variations in the carrier concentration and the activation energy for carrier hopping transport.

  16. Experimental and theoretical studies of a high temperature cesium-barium tacitron, with application to low voltage-high current inversion

    International Nuclear Information System (INIS)

    Murray, C.S.; El-Genk, M.S.

    1994-02-01

    A low voltage/high current switch refer-red as ''Cs-Ba tacitron'' is studied for use as a dc to ac inverter in high temperature and/or ionizing radiation environments. The operational characteristics of the Cs-Ba tacitron as a switch were investigated experimentally in three modes: (a) breakdown mode, (b) I-V mode, and (c) current modulation mode. Operation parameters measured include switching frequencies up to 20 kHz, hold-off voltages up to 200 V, current densities in excess of 15 A/CM 2 , switch power density of 1 kW/cm 2 , and a switching efficiency in excess of 90 % at collector voltages greater than 30 V. Also, if the discharge current is circuit limited to a value below the maximum thermal emission current density, the voltage drop is constant and below 3 V

  17. Elimination of bus voltage impact on temperature sensitive electrical parameter during turn-on transition for junction temperature estimation of high-power IGBT modules

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Blaabjerg, Frede

    2017-01-01

    Junction temperature is of great importance to safe operating area of IGBT modules. Various information of the IGBT operating state is reflected on electrical characteristics during turn-on transient. A unified extraction method for internal junction temperature via dynamic thermo......-sensitive electrical parameters (DTSEP) during turn-on transient is proposed. Two DTSEP, turn-on delay time (tdon) and the maximum increasing rate of collector current dic/dt(max), are combined to eliminate the bus voltage impact. Using the inherent emitter-auxiliary inductor LeE in high-power modules, the temperature......-dependent DTSEPs can be converted into a low-voltage and measurable signal. Finally, experiment results are exhibited to verify the effectiveness of proposed method....

  18. Characteristics and Breakdown Behaviors of Polysilicon Resistors for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Tang

    2015-01-01

    Full Text Available With the rapid development of the power integrated circuit technology, polysilicon resistors have been widely used not only in traditional CMOS circuits, but also in the high voltage applications. However, there have been few detailed reports about the polysilicon resistors’ characteristics, like voltage and temperature coefficients and breakdown behaviors which are critical parameters of high voltage applications. In this study, we experimentally find that the resistance of the polysilicon resistor with a relatively low doping concentration shows negative voltage and temperature coefficients, while that of the polysilicon resistor with a high doping concentration has positive voltage and temperature coefficients. Moreover, from the experimental results of breakdown voltages of the polysilicon resistors, it could be deduced that the breakdown of polysilicon resistors is thermally rather than electrically induced. We also proposed to add an N-type well underneath the oxide to increase the breakdown voltage in the vertical direction when the substrate is P-type doped.

  19. Electrochemical performance of lithium-ion capacitors evaluated under high temperature and high voltage stress using redox stable electrolytes and additives

    Science.gov (United States)

    Boltersdorf, Jonathan; Delp, Samuel A.; Yan, Jin; Cao, Ben; Zheng, Jim P.; Jow, T. Richard; Read, Jeffrey A.

    2018-01-01

    Lithium-ion capacitors (LICs) were investigated for high power, moderate energy density applications for operation in extreme environments with prolonged cycle-life performance. The LICs were assembled as three-layered pouch cells in an asymmetric configuration employing Faradaic pre-lithiated hard carbon anodes and non-Faradaic ion adsorption-desorption activated carbon (AC) cathodes. The capacity retention was measured under high stress conditions, while the design factor explored was electrolyte formulation using a set of carbonates and electrolyte additives, with a focus on their stability. The LIC cells were evaluated using critical performance tests under the following high stress conditions: long-term voltage floating-cycling stability at room temperature (2.2-3.8 V), high temperature storage at 3.8 V, and charge voltages up to 4.4 V. The rate performance of different electrolytes and additives was measured after the initial LIC cell formation for a 1C-10C rate. The presence of vinylene carbonate (VC) and tris (trimethylsilyl) phosphate (TMSP) were found to be essential to the improved electrochemical performance of the LIC cells under all testing conditions.

  20. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability

  1. Design and realization of high voltage disconnector condition monitoring system

    Science.gov (United States)

    Shi, Jinrui; Xu, Tianyang; Yang, Shuixian; Li, Buoyang

    2017-08-01

    The operation status of the high voltage disconnector directly affects the safe and stable operation of the power system. This article uses the wireless frequency hopping communication technology of the communication module to achieve the temperature acquisition of the switch contacts and high voltage bus, to introduce the current value of the loop in ECS, and judge the operation status of the disconnector by considering the ambient temperature, calculating the temperature rise; And through the acquisition of the current of drive motor in the process of switch closing and opening, and fault diagnosis of the disconnector by analyzing the change rule of the drive motor current, the condition monitoring of the high voltage disconnector is realized.

  2. High voltage systems

    International Nuclear Information System (INIS)

    Martin, M.

    1991-01-01

    Industrial processes usually require electrical power. This power is used to drive motors, to heat materials, or in electrochemical processes. Often the power requirements of a plant require the electric power to be delivered at high voltage. In this paper high voltage is considered any voltage over 600 V. This voltage could be as high as 138,000 V for some very large facilities. The characteristics of this voltage and the enormous amounts of power being transmitted necessitate special safety considerations. Safety must be considered during the four activities associated with a high voltage electrical system. These activities are: Design; Installation; Operation; and Maintenance

  3. The research of high voltage switchgear detecting unit

    Science.gov (United States)

    Ji, Tong; Xie, Wei; Wang, Xiaoqing; Zhang, Jinbo

    2017-07-01

    In order to understand the status of the high voltage switch in the whole life circle, you must monitor the mechanical and electrical parameters that affect device health. So this paper gives a new high voltage switchgear detecting unit based on ARM technology. It can measure closing-opening mechanical wave, storage motor current wave and contactor temperature to judge the device’s health status. When something goes wrong, it can be on alert and give some advice. The practice showed that it can meet the requirements of circuit breaker mechanical properties temperature online detection.

  4. Voltage, Temperature, Frequency Margin Test Report

    DEFF Research Database (Denmark)

    Denver, Troelz

    1999-01-01

    The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation......The purpose of the tests is to establish the camera functionality when it is exposed to an extreme environment for prolonged periods, thus simulating the end of life performance. This environment covers temperature, input clock frequency and supply voltage variation...

  5. Simulation of temperature field for temperature-controlled radio frequency ablation using a hyperbolic bioheat equation and temperature-varied voltage calibration: a liver-mimicking phantom study.

    Science.gov (United States)

    Zhang, Man; Zhou, Zhuhuang; Wu, Shuicai; Lin, Lan; Gao, Hongjian; Feng, Yusheng

    2015-12-21

    This study aims at improving the accuracy of temperature simulation for temperature-controlled radio frequency ablation (RFA). We proposed a new voltage-calibration method in the simulation and investigated the feasibility of a hyperbolic bioheat equation (HBE) in the RFA simulation with longer durations and higher power. A total of 40 RFA experiments was conducted in a liver-mimicking phantom. Four mathematical models with multipolar electrodes were developed by the finite element method in COMSOL software: HBE with/without voltage calibration, and the Pennes bioheat equation (PBE) with/without voltage calibration. The temperature-varied voltage calibration used in the simulation was calculated from an experimental power output and temperature-dependent resistance of liver tissue. We employed the HBE in simulation by considering the delay time τ of 16 s. First, for simulations by each kind of bioheat equation (PBE or HBE), we compared the differences between the temperature-varied voltage-calibration and the fixed-voltage values used in the simulations. Then, the comparisons were conducted between the PBE and the HBE in the simulations with temperature-varied voltage calibration. We verified the simulation results by experimental temperature measurements on nine specific points of the tissue phantom. The results showed that: (1) the proposed voltage-calibration method improved the simulation accuracy of temperature-controlled RFA for both the PBE and the HBE, and (2) for temperature-controlled RFA simulation with the temperature-varied voltage calibration, the HBE method was 0.55 °C more accurate than the PBE method. The proposed temperature-varied voltage calibration may be useful in temperature field simulations of temperature-controlled RFA. Besides, the HBE may be used as an alternative in the simulation of long-duration high-power RFA.

  6. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  7. High voltage holding in the negative ion sources with cesium deposition

    Energy Technology Data Exchange (ETDEWEB)

    Belchenko, Yu.; Abdrashitov, G.; Ivanov, A.; Sanin, A.; Sotnikov, O., E-mail: O.Z.Sotnikov@inp.nsk.su [Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-15

    High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed.

  8. High voltage diagnostics on electrical insulation of supersonducting magnets

    International Nuclear Information System (INIS)

    Irmisch, M.

    1995-12-01

    The high voltage (HV) performance of superconducting magnets of large dimensions, e.g. as needed in fusion reactors, is a challange in the field of high voltage technology, i.e. especially in the field of cryogenic high voltage components and with respect to questions of HV insulation diagnostics at low temperature. By using the development of POLO - a superconducting prototype coil of a tokamak poloidal field coil - as an example, this work deals with special problems of how to get use of conventional HV test techniques for diagnostics under special cryogenic boundary conditions. As a first approach to gain experience in the field of phase resolved partial discharge (PRPD) measurements during operation of a superconductive coil, the POLO coil was subject to several high voltage tests. Compared with DC insulation resistance measurements and capacitive impulse voltage discharges to the coil, the AC PD measurements have been the only way to observe special characteristics of the electrical insulation with respect to the cooling down of the coil from 300 K to 4.2 K. The PRPD measurement technique thereby has proofed as a suitable diagnostic tool. This work can serve as basic data to be comparable within further projects of electrical insulation diagnostics at cryogenic temperatures. (orig.)

  9. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D.C.

    2013-12-16

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  10. Comparison of Conductor-Temperature Calculations Based on Different Radial-Position-Temperature Detections for High-Voltage Power Cable

    Directory of Open Access Journals (Sweden)

    Lin Yang

    2018-01-01

    Full Text Available In this paper, the calculation of the conductor temperature is related to the temperature sensor position in high-voltage power cables and four thermal circuits—based on the temperatures of insulation shield, the center of waterproof compound, the aluminum sheath, and the jacket surface are established to calculate the conductor temperature. To examine the effectiveness of conductor temperature calculations, simulation models based on flow characteristics of the air gap between the waterproof compound and the aluminum are built up, and thermocouples are placed at the four radial positions in a 110 kV cross-linked polyethylene (XLPE insulated power cable to measure the temperatures of four positions. In measurements, six cases of current heating test under three laying environments, such as duct, water, and backfilled soil were carried out. Both errors of the conductor temperature calculation and the simulation based on the temperature of insulation shield were significantly smaller than others under all laying environments. It is the uncertainty of the thermal resistivity, together with the difference of the initial temperature of each radial position by the solar radiation, which led to the above results. The thermal capacitance of the air has little impact on errors. The thermal resistance of the air gap is the largest error source. Compromising the temperature-estimation accuracy and the insulation-damage risk, the waterproof compound is the recommended sensor position to improve the accuracy of conductor-temperature calculation. When the thermal resistances were calculated correctly, the aluminum sheath is also the recommended sensor position besides the waterproof compound.

  11. Technological Aspects: High Voltage

    International Nuclear Information System (INIS)

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered. (author)

  12. High voltage investigations for ITER coils

    International Nuclear Information System (INIS)

    Fink, S.; Fietz, W.H.

    2006-01-01

    The superconducting ITER magnets will be excited with high voltage during operation and fast discharge. Because the coils are complex systems the internal voltage distribution can differ to a large extent from the ideal linear voltage distribution. In case of fast excitations internal voltages between conductor and radial plate of a TF coil can be even higher than the terminal voltage of 3.5 kV to ground which appears during a fast discharge without a fault. Hence the determination of the transient voltage distribution is important for a proper insulation co-ordination and will provide a necessary basis for the verification of the individual insulation design and the choice of test voltages and waveforms. Especially the extent of internal overvoltages in case of failures, e. g. malfunction of discharge units and / or arcing is of special interest. Transient calculations for the ITER TF coil system have been performed for fast discharge and fault scenarios to define test voltages for ITER TF. The conductor and radial plate insulation of the ITER TF Model Coil were exposed at room temperature to test voltages derived from the results from these calculations. Breakdown appeared during the highest AC voltage step. A fault scenario for the TF fast discharge system is presented where one fault triggers a second fault, leading to considerable voltage stress. In addition a FEM model of Poloidal Field Coil 3 for the determination of the parameters of a detailed network model is presented in order to prepare detailed investigations of the transient voltage behaviour of the PF coils. (author)

  13. The current–voltage and capacitance–voltage characteristics at high temperatures of Au Schottky contact to n-type GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Özerli, Halil; Karteri, İbrahim [Department of Materials Science And Engineering, Kahramanmaraş Sütçü İmam University, 46100 Kahramanmaraş (Turkey); Karataş, Şükrü, E-mail: skaratas@ksu.edu.tr [Department of Materials Science And Engineering, Kahramanmaraş Sütçü İmam University, 46100 Kahramanmaraş (Turkey); Department of Physics, Kahramanmaraş Sütçü İmam University, 46100 Kahramanmaraş (Turkey); Altindal, Şemsettin [Department of Physics, Gazi University, 06100 Ankara (Turkey)

    2014-05-01

    Highlights: • The electronic parameters of the diode under temperature were investigated. • The barrier heights have a Gaussian distribution. • Au/n-GaAs diode exhibits a rectification behavior. - Abstract: We have investigated the temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Au/n-GaAs Schottky barrier diodes (SBDs) in the temperature range of 280–415 K. The barrier height for the Au/n-type GaAs SBDs from the I–V and C–V characteristics have varied from 0.901 eV to 0.963 eV (I–V) and 1.234 eV to 0.967 eV (C–V), and the ideality factor (n) from 1.45 to 1.69 in the temperature range 280–415 K. The conventional Richardson plots are found to be linear in the temperature range measured. Both the ln(I{sub 0}/T{sup 2}) versus (kT){sup −1} and ln(I{sub 0}/T{sup 2}) versus (nkT){sup −1} plots gives a straight line corresponding to activation energies 0.773 eV and 0.870 eV, respectively. A Φ{sub b0} versus 1/T plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and values of Φ{sup ¯}{sub b0} = 1.071 eV and σ{sub 0} = 0.094 V for the mean BH and zero-bias standard deviation have been obtained from this plot.

  14. The current–voltage and capacitance–voltage characteristics at high temperatures of Au Schottky contact to n-type GaAs

    International Nuclear Information System (INIS)

    Özerli, Halil; Karteri, İbrahim; Karataş, Şükrü; Altindal, Şemsettin

    2014-01-01

    Highlights: • The electronic parameters of the diode under temperature were investigated. • The barrier heights have a Gaussian distribution. • Au/n-GaAs diode exhibits a rectification behavior. - Abstract: We have investigated the temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Au/n-GaAs Schottky barrier diodes (SBDs) in the temperature range of 280–415 K. The barrier height for the Au/n-type GaAs SBDs from the I–V and C–V characteristics have varied from 0.901 eV to 0.963 eV (I–V) and 1.234 eV to 0.967 eV (C–V), and the ideality factor (n) from 1.45 to 1.69 in the temperature range 280–415 K. The conventional Richardson plots are found to be linear in the temperature range measured. Both the ln(I 0 /T 2 ) versus (kT) −1 and ln(I 0 /T 2 ) versus (nkT) −1 plots gives a straight line corresponding to activation energies 0.773 eV and 0.870 eV, respectively. A Φ b0 versus 1/T plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and values of Φ ¯ b0 = 1.071 eV and σ 0 = 0.094 V for the mean BH and zero-bias standard deviation have been obtained from this plot

  15. Energy harvesting in high voltage measuring techniques

    International Nuclear Information System (INIS)

    Żyłka, Pawel; Doliński, Marcin

    2016-01-01

    The paper discusses selected problems related to application of energy harvesting (that is, generating electricity from surplus energy present in the environment) to supply autonomous ultra-low-power measurement systems applicable in high voltage engineering. As a practical example of such implementation a laboratory model of a remote temperature sensor is presented, which is self-powered by heat generated in a current-carrying busbar in HV- switchgear. Presented system exploits a thermoelectric harvester based on a passively cooled Peltier module supplying micro-power low-voltage dc-dc converter driving energy-efficient temperature sensor, microcontroller and a fibre-optic transmitter. Performance of the model in laboratory simulated conditions are presented and discussed. (paper)

  16. Suppressing voltage transients in high voltage power supplies

    International Nuclear Information System (INIS)

    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.)

  17. Multiple current peaks in room-temperature atmospheric pressure homogenous dielectric barrier discharge plasma excited by high-voltage tunable nanosecond pulse in air

    Energy Technology Data Exchange (ETDEWEB)

    Yang, De-Zheng; Wang, Wen-Chun; Zhang, Shuai; Tang, Kai; Liu, Zhi-jie; Wang, Sen [Key Lab of Materials Modification, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

    2013-05-13

    Room temperature homogenous dielectric barrier discharge plasma with high instantaneous energy efficiency is acquired by using nanosecond pulse voltage with 20-200 ns tunable pulse width. Increasing the voltage pulse width can lead to the generation of regular and stable multiple current peaks in each discharge sequence. When the voltage pulse width is 200 ns, more than 5 organized current peaks can be observed under 26 kV peak voltage. Investigation also shows that the organized multiple current peaks only appear in homogenous discharge mode. When the discharge is filament mode, organized multiple current peaks are replaced by chaotic filament current peaks.

  18. Reversible calcium alloying enables a practical room-temperature rechargeable calcium-ion battery with a high discharge voltage

    Science.gov (United States)

    Wang, Meng; Jiang, Chunlei; Zhang, Songquan; Song, Xiaohe; Tang, Yongbing; Cheng, Hui-Ming

    2018-06-01

    Calcium-ion batteries (CIBs) are attractive candidates for energy storage because Ca2+ has low polarization and a reduction potential (-2.87 V versus standard hydrogen electrode, SHE) close to that of Li+ (-3.04 V versus SHE), promising a wide voltage window for a full battery. However, their development is limited by difficulties such as the lack of proper cathode/anode materials for reversible Ca2+ intercalation/de-intercalation, low working voltages (performance. Here, we report a CIB that can work stably at room temperature in a new cell configuration using graphite as the cathode and tin foils as the anode as well as the current collector. This CIB operates on a highly reversible electrochemical reaction that combines hexafluorophosphate intercalation/de-intercalation at the cathode and a Ca-involved alloying/de-alloying reaction at the anode. An optimized CIB exhibits a working voltage of up to 4.45 V with capacity retention of 95% after 350 cycles.

  19. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  20. Variation of microchannel plate resistance with temperature and applied voltage

    International Nuclear Information System (INIS)

    Pearson, J.F.; Fraser, G.W.; Whiteley, M.J.

    1987-01-01

    The resistance of microchannel plate electron multiplier is well known to be a function of both applied voltage and detector temperature. We show that the apparent variation of resistance with bias voltage is simply due to plate temperature increases resulting from resistive heating. (orig.)

  1. Influence of dump voltage and allowable temperature rise on stabilizer requirements in superconducting coils

    International Nuclear Information System (INIS)

    Schwenterly, S.W.

    1988-01-01

    A superconducting winding must have enough stabilizer to satisfy two sets of criteria. During normal operation, the amount of stabilizer must be large enough either to make the coil unconditionally stable or to give a certain desired stability margin. Once a dump occurs, the amount of stabilizer must be large enough to carry the current without generating excessive dump voltages or allowing the winding to exceed a certain maximum temperature (and maximum pressure, in the case of force-cooled coils). The voltage criterion often dominates for very large coil systems, but it is frequently ignored in initial design studies. This paper gives some simple relations between the dump voltage and the stored energy, temperature rise, and coil geometry that are useful in scooping the required amount of stabilizer. Comparison with some recently proposed fusion magnet system designs indicates that excessive dump voltages could result in some cases. High-temperature superconductors may require more stabilizer than the conventional alloys. Calculations with simple model coil systems indicate how trade-offs between various coil parameters affect the dump voltage. 12 refs., 1 fig., 1 tab

  2. Reliability of supply of switchgear for auxiliary low voltage in substations extra high voltage to high voltage

    Directory of Open Access Journals (Sweden)

    Perić Dragoslav M.

    2015-01-01

    Full Text Available Switchgear for auxiliary low voltage in substations (SS of extra high voltages (EHV to high voltage (HV - SS EHV/HV kV/kV is of special interest for the functioning of these important SS, as it provides a supply for system of protection and other vital functions of SS. The article addresses several characteristic examples involving MV lines with varying degrees of independence of their supply, and the possible application of direct transformation EHV/LV through special voltage transformers. Auxiliary sources such as inverters and diesel generators, which have limited power and expensive energy, are also used for the supply of switchgear for auxiliary low voltage. Corresponding reliability indices are calculated for all examples including mean expected annual engagement of diesel generators. The applicability of certain solutions of switchgear for auxiliary low voltage SS EHV/HV, taking into account their reliability, feasibility and cost-effectiveness is analyzed too. In particular, the analysis of applications of direct transformation EHV/LV for supply of switchgear for auxiliary low voltage, for both new and existing SS EHV/HV.

  3. Development of high voltage PEEK wire with radiation-resistance and cryogenic characteristics

    International Nuclear Information System (INIS)

    Fujita, T.; Hirata, T.; Araki, S.; Ohara, H.; Nishimura, H.

    1989-01-01

    High voltage electric wires insulated with highly-refined polyetheretherketone (PEEK) have been developed for the wiring in fusion reactors, where the wire is required to withstand high voltage under high vacuum up to 10 -5 Torr. The PEEK wires having the advantages of PEEK resin including superior radiation resistance and cryogenic characteristics are usable over a wide range of temperature and in radiation fields. The results of withstand voltage tests proved that the PEEK wires exceeding 0.8 mm in insulation thickness withstand such specified high voltage conditions as 24 kV for 1 minutes by 10 times and 6.6 kV for 110 hours. The results also revealed that the withstand voltage is improved by providing a jacket layer over the insulation and decreased by periodical voltage charge, by bending of the specimen and by water in the conductor. This paper deal with the withstand voltage test results under varied conditions of the PEEK wires. (author)

  4. Study on temperature dependence of output voltage of electrochemical detector for environmental neutrinos

    International Nuclear Information System (INIS)

    Halim, Md Abdul; Ishibashi, Kenji; Arima, Hidehiko; Terao, Norichika

    2006-01-01

    An electrochemical detector with biological material has been applied for the detection of neutrinos on the basis of a new hypothesis. The detector consisted of two electrodes with raw silk and purified water, and gave an appreciable output voltage. The reproducibility of the experimental results was as good as 99.4% at temperature of 300 K. The temperature dependence of the voltage of the detector was studied at 280, 290, 300 and 310 K. Among them, the detector at 310 K produced the highest output voltage and reached 104 mV in 16 days, whereas that at 280 K generated the lowest voltage and it was as low as 1.2 mV in 16 days. The detectors working at 290 and 300 K produced the voltages 18 and 57 mV in 16 days, respectively. The output voltages of the detector increased with temperature and were in good agreement in spite of the history of temperature. The internal resistance and electromotive force (internal voltage) of the experimental detector were obtained at each temperature by individual analysis and least square fitting method. It was found that the electromotive force was almost constant for these temperatures while the internal resistance showed a large dependence on temperature. The reduction of the output voltage with temperature is dominated by this behavior of internal resistance. (author)

  5. A high-voltage equipment (high voltage supply, high voltage pulse generators, resonant charging inductance, synchro-instruments for gyrotron frequency measurements) for plasma applications

    International Nuclear Information System (INIS)

    Spassov, Velin

    1996-01-01

    This document reports my activities as visitor-professor at the Gyrotron Project - INPE Plasma Laboratory. The main objective of my activities was designing, construction and testing a suitable high-voltage pulse generator for plasma applications, and efforts were concentrated on the following points: Design of high-voltage resonant power supply with tunable output (0 - 50 kV) for line-type high voltage pulse generator; design of line-type pulse generator (4 microseconds pulse duration, 0 - 25 kV tunable voltage) for non linear loads such as a gyrotron and P III reactor; design of resonant charging inductance for resonant line-type pulse generator, and design of high resolution synchro instrument for gyrotron frequency measurement. (author)

  6. Observation of asymmetric transverse voltage in granular high-T c superconductors

    International Nuclear Information System (INIS)

    Luz, M.S. da; Carvalho, F.J.H. de; Santos, C.A.M. dos; Shigue, C.Y.; Machado, A.J.S.; Ricardo da Silva, R.

    2005-01-01

    This work reports the influence of the granularity on the transverse voltage as a function of the temperature, V XY (T), in polycrystalline samples of Bi 2 Sr 2 Ca 0.8 Pr 0.2 Cu 2 O 8+δ composition. It is observed nonzero transverse voltage at zero external magnetic field in the vicinity of the superconducting transition while far away from it, both above and below, no such voltage was detected. Measurements of V XY (T) in both directions of magnetic field allowed to calculate the symmetric and asymmetric transverse voltages in the full range of the applied magnetic field studied (zero up to 9 T). The symmetric transverse voltage as a function of the temperature presents sign reversal of the Hall resistance and positive Hall voltage at normal state such as expected for hole-doped high critical temperature superconductors. On the other hand, the asymmetric component of V XY (T) shows a peak near the superconducting transition which has been recently reported in literature. V XY (T) curves measured in a sample with double superconducting transition, which was confirmed by ac-susceptibility measurements and hysteresis loops of the magneto-resistance, present two peaks in the asymmetric component. These peaks are related to the intergranular and intragranular transitions and can be explained within the framework of Josephson and Abrikosov vortices and anti-vortices motion. By comparing the temperature dependence of the asymmetric transverse voltage and the derivative of longitudinal voltage is possible to observe a specific relation between both transport properties, which is noted to be valid not only at zero applied magnetic field but also under applied field

  7. High-voltage, high-current, solid-state closing switch

    Science.gov (United States)

    Focia, Ronald Jeffrey

    2017-08-22

    A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

  8. A novel on-chip high to low voltage power conversion circuit

    International Nuclear Information System (INIS)

    Wang Hui; Wang Songlin; Mou Zaixin; Guo Baolong; Lai Xinquan; Ye Qiang; Li Xianrui

    2009-01-01

    A novel power supply transform technique for high voltage IC based on the TSMC 0.6 μm BCD process is achieved. An adjustable bandgap voltage reference is presented which is different from the traditional power supply transform technique. It can be used as an internal power supply for high voltage IC by using the push-pull output stage to enhance its load capability. High-order temperature compensated circuit is designed to ensure the precision of the reference. Only 0.01 mm 2 area is occupied using this novel power supply technique. Compared with traditional technique, 50% of the area is saved, 40% quiescent power loss is decreased, and the temperature coefficient of the reference is only 4.48 ppm/deg. C. Compared with the traditional LDO (low dropout) regulator, this power conversion architecture does not need external output capacitance and decreases the chip-pin and external components, so the PCB area and design cost are also decreased. The testing results show that this circuit works well.

  9. A novel on-chip high to low voltage power conversion circuit

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hui; Wang Songlin; Mou Zaixin; Guo Baolong [Institute of Mechano-electronic Engineering, Xidian University, Xi' an 71007 (China); Lai Xinquan; Ye Qiang; Li Xianrui, E-mail: whui94@126.co [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China)

    2009-03-15

    A novel power supply transform technique for high voltage IC based on the TSMC 0.6 mum BCD process is achieved. An adjustable bandgap voltage reference is presented which is different from the traditional power supply transform technique. It can be used as an internal power supply for high voltage IC by using the push-pull output stage to enhance its load capability. High-order temperature compensated circuit is designed to ensure the precision of the reference. Only 0.01 mm{sup 2} area is occupied using this novel power supply technique. Compared with traditional technique, 50% of the area is saved, 40% quiescent power loss is decreased, and the temperature coefficient of the reference is only 4.48 ppm/deg. C. Compared with the traditional LDO (low dropout) regulator, this power conversion architecture does not need external output capacitance and decreases the chip-pin and external components, so the PCB area and design cost are also decreased. The testing results show that this circuit works well.

  10. CMOS-compatible high-voltage integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Parpia, Z

    1988-01-01

    Considerable savings in cost and development time can be achieved if high-voltage ICs (HVICs) are fabricated in an existing low-voltage process. In this thesis, the feasibility of fabricating HVICs in a standard CMOS process is investigated. The high-voltage capabilities of an existing 5-{mu}m CMOS process are first studied. High-voltage n- and p-channel transistors with breakdown voltages of 50 and 190 V, respectively, were fabricated without any modifications to the process under consideration. SPICE models for these transistors are developed, and their accuracy verified by comparison with experimental results. In addition, the effect of the interconnect metallization on the high-voltage performance of these devices is also examined. Polysilicon field plates are found to be effective in preventing premature interconnect induced breakdown in these devices. A novel high-voltage transistor structure, the insulated base transistor (IBT), based on a merged MOS-bipolar concept, is proposed and implemented. In order to enhance the high-voltage device capabilities, an improved CMOS-compatible HVIC process using junction isolation is developed.

  11. Prediction of windings temperature rise in induction motors supplied with distorted voltage

    Energy Technology Data Exchange (ETDEWEB)

    Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Street 83, 81-225 Gdynia (Poland)

    2008-04-15

    One of the features of ship power systems is a different level and intensity of disturbances appearing during routine operation - the rms voltage value and frequency deviation, voltage unbalance and waveform voltage distortion. As a result, marine induction machines are exposed to overheating due to the lowered voltage quality. This paper is devoted to windings temperature rise prediction in marine induction cage machines supplied with distorted voltage, which means real voltage conditions. The proposed method of prediction does not require detailed knowledge of the thermal properties of a machine. Although the method was developed for marine induction motors, it is applicable for industry machines supplied with distorted voltage. It can also be generalized and used for estimation of the steady state windings temperature rise of any electrical machinery in various work conditions. (author)

  12. Prediction of windings temperature rise in induction motors supplied with distorted voltage

    International Nuclear Information System (INIS)

    Gnacinski, P.

    2008-01-01

    One of the features of ship power systems is a different level and intensity of disturbances appearing during routine operation - the rms voltage value and frequency deviation, voltage unbalance and waveform voltage distortion. As a result, marine induction machines are exposed to overheating due to the lowered voltage quality. This paper is devoted to windings temperature rise prediction in marine induction cage machines supplied with distorted voltage, which means real voltage conditions. The proposed method of prediction does not require detailed knowledge of the thermal properties of a machine. Although the method was developed for marine induction motors, it is applicable for industry machines supplied with distorted voltage. It can also be generalized and used for estimation of the steady state windings temperature rise of any electrical machinery in various work conditions

  13. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2014-07-01

    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  14. PC-based control of a high-voltage injector

    International Nuclear Information System (INIS)

    Constantin, F.

    1998-01-01

    The stability of high voltage injectors is one of the major problems in any accelerator system. Most of the troubles encountered in the normal operation of an accelerator are connected with the ion source and associated high voltage platforms, regardless of the source or high voltage generator type. The quality of the ion beam injected in the accelerator strongly depends on the power supplies used in the injector and on the ability to control the non-electrical parameters (gas-flow, temperature, etc.). A wide used method in controlling is based on optical links between high-voltage platform and computer, the adjustments being more or less automated. Although the method mentioned above can be still useful in injector control, a different approach is presented in this work, i.e., the computer itself is placed inside the high-voltage terminal. Only one optical link is still necessary to connect this computer with an user-friendly host at ground potential. Requirements: - varying and monitoring the filament current; - gas flow control in the ion source; - reading the vacuum values; - current and voltage control for the anodic, magnet, extraction, suppression and lens' sources. Even in the high voltage terminal there are compartments with different voltages regardless the floating ground. In our injector the extraction voltage is applied on the top of the ion source including the filament and the anodic voltage. The extraction voltage is of maximum 30 kV. In this situation a second optical link is required to transfer the control for the anodic and magnet source power supply assuming the dedicated computer on the floating ground. One PC is placed inside the high voltage terminal and one PC outside the injector. The optical link (more precisely two optical wires) connects the serial ports. The inside computer is equipped with two multipurpose ADC/DAC and digital I/O card. They permit to read or output DC levels ranging between 0 to 10 volts or TTL signals. The filament

  15. Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender

    2012-01-01

    We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 C. The previously observed maximum drift of +/- 10 mV of the reference offset voltage at 600 C was reduced to within +/- 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 C.

  16. Design and development of high voltage and high frequency center tapped transformer for HVDC test generator

    International Nuclear Information System (INIS)

    Thaker, Urmil; Saurabh Kumar; Amal, S.; Baruah, U.K.; Bhatt, Animesh

    2015-01-01

    A High Voltage center tapped transformer for high frequency application had been designed, fabricated, and tested. It was designed as a part of 200 kV HVDC Test Generator. The High Frequency operation of transformer increases power density. Therefore it is possible to reduce power supply volume. The step up ratio in High Voltage transformer is limited due to stray capacitance and leakage inductance. The limit was overcome by winding multi secondary outputs. Switching frequency of transformer was 15.8 kHz. Input and output voltages of transformer were 270V and 16.5kV-0V-16.5kV respectively. Power rating of transformer is 7kVA. High Voltage transformer with various winding and core arrangement was fabricated to check variation in electrical characteristics. The transformer used a ferrite core (E Type) and nylon insulated primary and secondary bobbins. Two set of E-E geometry cores had been stacked in order to achieve the estimated core volume. Compared with traditional high voltage transformer, this transformer had good thermal behavior, good line insulation properties and a high power density. In this poster, design procedures, development stages and test results of high voltage and high frequency transformer are presented. Results of various parameters such as transformer loss, temperature rise, insulation properties, impedance of primary and secondary winding, and voltage regulation are discussed. (author)

  17. Voltage regulator for generator

    Energy Technology Data Exchange (ETDEWEB)

    Naoi, K

    1989-01-17

    It is an object of this invention to provide a voltage regulator for a generator charging a battery, wherein even if the ambient temperature at the voltage regulator rises abnormally high, possible thermal breakage of the semiconductor elements constituting the voltage regulator can be avoided. A feature of this invention is that the semiconductor elements can be protected from thermal breakage, even at an abnormal ambient temperature rise at the voltage regulator for the battery charging generator, by controlling a maximum conduction ratio of a power transistor in the voltage regulator in accordance with the temperature at the voltage regulator. This is achieved through a switching device connected in series to the field coil of the generator and adapted to be controlled in accordance with an output voltage of the generator and the ambient temperature at the voltage regulator. 6 figs.

  18. High performance Si nanowire field-effect-transistors based on a CMOS inverter with tunable threshold voltage.

    Science.gov (United States)

    Van, Ngoc Huynh; Lee, Jae-Hyun; Sohn, Jung Inn; Cha, Seung Nam; Whang, Dongmok; Kim, Jong Min; Kang, Dae Joon

    2014-05-21

    We successfully fabricated nanowire-based complementary metal-oxide semiconductor (NWCMOS) inverter devices by utilizing n- and p-type Si nanowire field-effect-transistors (NWFETs) via a low-temperature fabrication processing technique. We demonstrate that NWCMOS inverter devices can be operated at less than 1 V, a significantly lower voltage than that of typical thin-film based complementary metal-oxide semiconductor (CMOS) inverter devices. This low-voltage operation was accomplished by controlling the threshold voltage of the n-type Si NWFETs through effective management of the nanowire (NW) doping concentration, while realizing high voltage gain (>10) and ultra-low static power dissipation (≤3 pW) for high-performance digital inverter devices. This result offers a viable means of fabricating high-performance, low-operation voltage, and high-density digital logic circuits using a low-temperature fabrication processing technique suitable for next-generation flexible electronics.

  19. Temporary over voltages in the high voltage networks

    International Nuclear Information System (INIS)

    Vukelja, Petar; Naumov, Radomir; Mrvic, Jovan; Minovski, Risto

    2001-01-01

    The paper treats the temporary over voltages that may arise in the high voltage networks as a result of: ground faults, loss of load, loss of one or two phases and switching operation. Based on the analysis, the measures for their limitation are proposed. (Original)

  20. Two types of photomultiplier voltage dividers for high and changing count rates

    International Nuclear Information System (INIS)

    Reiter, W.L.; Stengl, G.

    1980-01-01

    We report on the design of two types of voltage distribution circuits for high stability photomultiplier operation. 'Type A' voltage divider is an ohmic voltage divider with high bleeder current (up to 10 mA) and the resistor chain split at one of the last dynodes, usually the dynode where the analog signal is derived from. This simple constructive measure improves the stability of the dynode voltage by a factor of 5 compared with an unsplit conventional resistor chain. 'Type B' is a novel active voltage divider using cold cathode tubes ar regulating elements. This voltage divider exhibits excellent temperature stability (about 10 -4 / 0 C). With 'type B' an equal stability compared with conventional ohmic dividers can be achieved at a bleeder current smaller by one order of magnitude. Of course both concepts, 'type A' and 'type B', can be combined. (orig.)

  1. Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures

    Directory of Open Access Journals (Sweden)

    Ken-ichi Uchida

    2014-11-01

    Full Text Available We report temperature-dependent measurements of longitudinal spin Seebeck effects (LSSEs in Pt/Y_{3}Fe_{5}O_{12} (YIG/Pt systems in a high temperature range from room temperature to above the Curie temperature of YIG. The experimental results show that the magnitude of the LSSE voltage in the Pt/YIG/Pt systems rapidly decreases with increasing the temperature and disappears above the Curie temperature. The critical exponent of the LSSE voltage in the Pt/YIG/Pt systems at the Curie temperature is estimated to be 3, which is much greater than that for the magnetization curve of YIG. This difference highlights the fact that the mechanism of the LSSE cannot be explained in terms of simple static magnetic properties in YIG.

  2. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  3. Prediction of breakdown voltages in novel gases for high voltage insulation

    International Nuclear Information System (INIS)

    Koch, M.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF_6) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF_6 is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF_6 in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF_6 based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media

  4. Voltage and temperature dependence of the grain boundary tunneling magnetoresistance in manganites

    OpenAIRE

    Hoefener, C.; Philipp, J. B.; Klein, J.; Alff, L.; Marx, A.; Buechner, B.; Gross, R.

    2000-01-01

    We have performed a systematic analysis of the voltage and temperature dependence of the tunneling magnetoresistance (TMR) of grain boundaries (GB) in the manganites. We find a strong decrease of the TMR with increasing voltage and temperature. The decrease of the TMR with increasing voltage scales with an increase of the inelastic tunneling current due to multi-step inelastic tunneling via localized defect states in the tunneling barrier. This behavior can be described within a three-current...

  5. Prediction of breakdown voltages in novel gases for high voltage insulation

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M.

    2015-07-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF{sub 6}) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF{sub 6} is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF{sub 6} in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF{sub 6} based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media.

  6. LED-Based High-Voltage Lines Warning System

    Directory of Open Access Journals (Sweden)

    Eldar MUSA

    2013-04-01

    Full Text Available LED-based system, running with the current of high-voltage lines and converting the current flowing through the line into the light by using a toroid transformer, has been developed. The transformer’s primary winding is constituted by the high voltage power line. Toroidal core consists of two equal parts and the secondary windings are evenly placed on these two parts. The system is mounted on the high-voltage lines as a clamp. The secondary winding ends are connected in series by the connector on the clamp. LEDs are supplied by the voltage at the ends of secondary. Current flowing through highvoltage transmission lines is converted to voltage by the toroidal transformer and the light emitting LEDs are supplied with this voltage. The theory of the conversion of the current flowing through the line into the light is given. The system, running with the current of the line and converting the current into the light, has been developed. System has many application areas such as warning high voltage lines (warning winches to not hinder the high-voltage lines when working under the lines, warning planes to not touch the high-voltage lines, remote measurement of high-voltage line currents, and local illumination of the line area

  7. 76 FR 70721 - Voltage Coordination on High Voltage Grids; Notice of Staff Workshop

    Science.gov (United States)

    2011-11-15

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD12-5-000] Voltage Coordination on High Voltage Grids; Notice of Staff Workshop Take notice that the Federal Energy Regulatory Commission will hold a Workshop on Voltage Coordination on High Voltage Grids on Thursday, December 1, 2011...

  8. High-field quench behavior and dependence of hot spot temperature on quench detection voltage threshold in a Bi2Sr2CaCu2Ox coil

    International Nuclear Information System (INIS)

    Shen, Tengming; Ye, Liyang; Turrioni, Daniele; Li, Pei

    2015-01-01

    Small insert solenoids have been built using a multifilamentary Ag/Bi 2 Sr 2 CaCu 2 O x round wire insulated with a mullite sleeve (∼100 μm in thickness) and characterized in background fields to explore the quench behaviors and limits of Bi 2 Sr 2 CaCu 2 O x superconducting magnets, with an emphasis on assessing the impact of slow normal zone propagation on quench detection. Using heaters of various lengths to initiate a small normal zone, a coil was quenched safely more than 70 times without degradation, with the maximum coil temperature reaching 280 K. Coils withstood a resistive voltage of tens of mV for seconds without quenching, showing the high stability of these coils and suggesting that the quench detection voltage should be greater than 50 mV in order not to falsely trigger protection. The hot spot temperature for the resistive voltage of the normal zone to reach 100 mV increased from ∼40–∼80 K while increasing the operating wire current density J o from 89 A mm −2 to 354 A mm −2 , whereas for the voltage to reach 1 V, it increased from ∼60–∼140 K. This shows the increasing negative impact of slow normal zone propagation on quench detection with increasing J o and the need to limit the quench detection voltage to <1 V. These measurements, coupled with an analytical quench model, were used to assess the impact of the maximum allowable detection voltage and temperature upon quench detection on the quench protection, assuming a limit of the hot spot temperature to <300 K. (paper)

  9. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  10. A threshold-voltage model for small-scaled GaAs nMOSFET with stacked high-k gate dielectric

    International Nuclear Information System (INIS)

    Liu Chaowen; Xu Jingping; Liu Lu; Lu Hanhan; Huang Yuan

    2016-01-01

    A threshold-voltage model for a stacked high-k gate dielectric GaAs MOSFET is established by solving a two-dimensional Poisson's equation in channel and considering the short-channel, DIBL and quantum effects. The simulated results are in good agreement with the Silvaco TCAD data, confirming the correctness and validity of the model. Using the model, impacts of structural and physical parameters of the stack high-k gate dielectric on the threshold-voltage shift and the temperature characteristics of the threshold voltage are investigated. The results show that the stacked gate dielectric structure can effectively suppress the fringing-field and DIBL effects and improve the threshold and temperature characteristics, and on the other hand, the influence of temperature on the threshold voltage is overestimated if the quantum effect is ignored. (paper)

  11. A 5 V-to-3.3 V CMOS Linear Regulator with Three-Output Temperature-Independent Reference Voltages

    Directory of Open Access Journals (Sweden)

    San-Fu Wang

    2016-01-01

    Full Text Available This paper presents a 5 V-to-3.3 V linear regulator circuit, which uses 3.3 V CMOS transistors to replace the 5 V CMOS transistors. Thus, the complexity of the manufacturing semiconductor process can be improved. The proposed linear regulator is implemented by cascode architecture, which requires three different reference voltages as the bias voltages of its circuit. Thus, the three-output temperature-independent reference voltage circuit is proposed, which provides three accurate reference voltages simultaneously. The three-output temperature-independent reference voltages also can be used in other circuits of the chip. By using the proposed temperature-independent reference voltages, the proposed linear regulator can provide an accurate output voltage, and it is suitable for low cost, small size, and highly integrated system-on-chip (SoC applications. Moreover, the proposed linear regulator uses the cascode technique, which improves both the gain performance and the isolation performance. Therefore, the proposed linear regulator has a good performance in reference voltage to output voltage isolation. The voltage variation of the linear regulator is less than 2.153% in the temperature range of −40°C–120°C, and the power supply rejection ratio (PSRR is less than −42.8 dB at 60 Hz. The regulator can support 0~200 mA output current. The core area is less than 0.16 mm2.

  12. Electronic Current Transducer (ECT) for high voltage dc lines

    Science.gov (United States)

    Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

    1980-02-01

    The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

  13. Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

    Science.gov (United States)

    Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

    2011-01-01

    A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

  14. On-site voltage measurement with capacitive sensors on high voltage systems

    NARCIS (Netherlands)

    Wu, L.; Wouters, P.A.A.F.; Heesch, van E.J.M.; Steennis, E.F.

    2011-01-01

    In Extra/High-Voltage (EHV/HV) power systems, over-voltages occur e.g. due to transients or resonances. At places where no conventional voltage measurement devices can be installed, on-site measurement of these occurrences requires preferably non intrusive sensors, which can be installed with little

  15. High frequency breakdown voltage

    International Nuclear Information System (INIS)

    Chu, Thanh Duy.

    1992-03-01

    This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O degrees C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f c , the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f ce , is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions' concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance

  16. Ionization smoke detectors - the high-voltage issues

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Production of high-voltage ionization smoke detectors ceased in 1978 following the development of lower voltage models which used much smaller amounts of radioactive material. Despite this fact, thousands of high-voltage detectors are still in use today in many large UK companies. The major users argue that there is no reason to stop using their detectors if they are still fit for their purpose - many could last for another 15 to 20 years if properly maintained. But pressure has been mounting on businesses to replace all their high-voltage detectors with new low-voltage models within the next couple of years. This could place a huge financial burden on the companies concerned, with costs possibly running into millions of pounds. Traditionally, the major detector installers offered cleaning and maintenance services for high-voltage detectors to their customers but these have now been withdrawn. The installers give no clear reasons for this decision except that the detectors are outmoded and should be disposed of as soon as possible. Most users would agree that conversion to low-voltage types is inevitable but their main worry is the financial strain of replacing all their detectors - and associated equipment - in one go. They would prefer to phase out their high-voltage detectors in stages over a number of years to spread the costs of conversion. The problems of maintenance is discussed. A dual voltage fire alarm panel which allows the high-voltage detectors to be phased out is mentioned. (Author)

  17. High-frequency high-voltage high-power DC-to-DC converters

    Science.gov (United States)

    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.

  18. A threshold-voltage model for small-scaled GaAs nMOSFET with stacked high-k gate dielectric

    Science.gov (United States)

    Chaowen, Liu; Jingping, Xu; Lu, Liu; Hanhan, Lu; Yuan, Huang

    2016-02-01

    A threshold-voltage model for a stacked high-k gate dielectric GaAs MOSFET is established by solving a two-dimensional Poisson's equation in channel and considering the short-channel, DIBL and quantum effects. The simulated results are in good agreement with the Silvaco TCAD data, confirming the correctness and validity of the model. Using the model, impacts of structural and physical parameters of the stack high-k gate dielectric on the threshold-voltage shift and the temperature characteristics of the threshold voltage are investigated. The results show that the stacked gate dielectric structure can effectively suppress the fringing-field and DIBL effects and improve the threshold and temperature characteristics, and on the other hand, the influence of temperature on the threshold voltage is overestimated if the quantum effect is ignored. Project supported by the National Natural Science Foundation of China (No. 61176100).

  19. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  20. 30 CFR 75.804 - Underground high-voltage cables.

    Science.gov (United States)

    2010-07-01

    ... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section...

  1. High-voltage engineering and testing

    CERN Document Server

    Ryan, Hugh M

    2013-01-01

    This 3rd edition of High Voltage Engineering Testing describes strategic developments in the field and reflects on how they can best be managed. All the key components of high voltage and distribution systems are covered including electric power networks, UHV and HV. Distribution systems including HVDC and power electronic systems are also considered.

  2. Modular high voltage power supply for chemical analysis

    Science.gov (United States)

    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.

  3. High voltage designing of 300.000 Volt

    International Nuclear Information System (INIS)

    Hutapea, Sumihar.

    1978-01-01

    Some methods of designing a.c and d.c high voltage supplies are discussed. A high voltage supply for the Gama Research Centre accelerator is designed using transistor pulse generators. High voltage transformers being made using radio transistor ferrits as a core are also discussed. (author)

  4. 30 CFR 75.813 - High-voltage longwalls; scope.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwalls; scope. 75.813 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage longwalls; scope. Sections 75.814 through 75.822 of this...

  5. Temperature and Voltage Coupling to Channel Opening in Transient Receptor Potential Melastatin 8 (TRPM8)*♦

    Science.gov (United States)

    Raddatz, Natalia; Castillo, Juan P.; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-01-01

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca2+-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol−1. The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening. PMID:25352597

  6. Absolute Determination of High DC Voltages by Means of Frequency Measurement

    Science.gov (United States)

    Peier, Dirk; Schulz, Bernd

    1983-01-01

    A novel absolute measuring procedure is presented for the definition of fixed points of the voltage in the 100 kV range. The method is based on transit time measurements with accelerated electrons. By utilizing the selective interaction of a monoenergetic electron beam with the electromagnetic field of a special cavity resonator, the voltage is referred to fundamental constants and the base unit second. Possible balance voltages are indicated by a current detector. Experimental investigations are carried out with resonators in the normal conducting range. With a copper resonator operating at the temperature of boiling nitrogen (77 K), the relative uncertainty of the voltage points is estimated to be +/- 4 × 10-4. The technically realizable uncertainty can be reduced to +/- 1 × 10-5 by the proposed application of a superconducting niobium resonator. Thus this measuring device becomes suitable as a primary standard for the high-voltage range.

  7. A temperature monitor circuit with small voltage sensitivity using a topology-reconfigurable ring oscillator

    Science.gov (United States)

    Kishimoto, Tadashi; Ishihara, Tohru; Onodera, Hidetoshi

    2018-04-01

    In this paper, we propose a temperature monitor circuit that exhibits a small supply voltage sensitivity adopting a circuit topology of a reconfigurable ring oscillator. The circuit topology of the monitor is crafted such that the oscillation frequency is determined by the amount of subthreshold leakage current, which has an exponential dependence on temperature. Another important characteristic of the monitor is its small supply voltage sensitivity. The measured oscillation frequency of a test chip fabricated in a 65 nm CMOS process varies only 2.6% under a wide range of supply voltages from 0.4 to 1.0 V at room temperature. The temperature estimation error ranges from -0.3 to 0.4 °C over a temperature range of 10 to 100 °C.

  8. Computer controlled high voltage system

    Energy Technology Data Exchange (ETDEWEB)

    Kunov, B; Georgiev, G; Dimitrov, L [and others

    1996-12-31

    A multichannel computer controlled high-voltage power supply system is developed. The basic technical parameters of the system are: output voltage -100-3000 V, output current - 0-3 mA, maximum number of channels in one crate - 78. 3 refs.

  9. High voltage distributions in RPCs

    International Nuclear Information System (INIS)

    Inoue, Y.; Muranishi, Y.; Nakamura, M.; Nakano, E.; Takahashi, T.; Teramoto, Y.

    1996-01-01

    High voltage distributions on the inner surfaces of RPCs electrodes were calculated by using a two-dimensional resistor network model. The calculated result shows that the surface resistivity of the electrodes should be high, compared to their volume resistivity, to get a uniform high voltage over the surface. Our model predicts that the rate capabilities of RPCs should be inversely proportional to the thickness of the electrodes if the ratio of surface-to-volume resistivity is low. (orig.)

  10. High-voltage CMOS detectors

    International Nuclear Information System (INIS)

    Ehrler, F.; Blanco, R.; Leys, R.; Perić, I.

    2016-01-01

    High-voltage CMOS (HVCMOS) pixel sensors are depleted active pixel sensors implemented in standard commercial CMOS processes. The sensor element is the n-well/p-substrate diode. The sensor electronics are entirely placed inside the n-well which is at the same time used as the charge collection electrode. High voltage is used to deplete the part of the substrate around the n-well. HVCMOS sensors allow implementation of complex in-pixel electronics. This, together with fast signal collection, allows a good time resolution, which is required for particle tracking in high energy physics. HVCMOS sensors will be used in Mu3e experiment at PSI and are considered as an option for both ATLAS and CLIC (CERN). Radiation tolerance and time walk compensation have been tested and results are presented. - Highlights: • High-voltage CMOS sensors will be used in Mu3e experiment at PSI (Switzerland). • HVCMOS sensors are considered as an option for ATLAS (LHC/CERN) and CLIC (CERN). • Efficiency of more than 95% (99%) has been measured with (un-)irradiated chips. • The time resolution measured in the beam tests is nearly 100 ns. • We plan to improve time resolution and efficiency by using high-resistive substrate.

  11. High-voltage CMOS detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ehrler, F., E-mail: felix.ehrler@student.kit.edu; Blanco, R.; Leys, R.; Perić, I.

    2016-07-11

    High-voltage CMOS (HVCMOS) pixel sensors are depleted active pixel sensors implemented in standard commercial CMOS processes. The sensor element is the n-well/p-substrate diode. The sensor electronics are entirely placed inside the n-well which is at the same time used as the charge collection electrode. High voltage is used to deplete the part of the substrate around the n-well. HVCMOS sensors allow implementation of complex in-pixel electronics. This, together with fast signal collection, allows a good time resolution, which is required for particle tracking in high energy physics. HVCMOS sensors will be used in Mu3e experiment at PSI and are considered as an option for both ATLAS and CLIC (CERN). Radiation tolerance and time walk compensation have been tested and results are presented. - Highlights: • High-voltage CMOS sensors will be used in Mu3e experiment at PSI (Switzerland). • HVCMOS sensors are considered as an option for ATLAS (LHC/CERN) and CLIC (CERN). • Efficiency of more than 95% (99%) has been measured with (un-)irradiated chips. • The time resolution measured in the beam tests is nearly 100 ns. • We plan to improve time resolution and efficiency by using high-resistive substrate.

  12. High voltage high brightness electron accelerators with MITL voltage adder coupled to foilless diodes

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Poukey, J.W.; Frost, C.A.; Shope, S.L.; Halbleib, J.A.; Turman, B.N.

    1993-01-01

    During the last ten years the authors have extensively studied the physics and operation of magnetically-immersed electron foilless diodes. Most of these sources were utilized as injectors to high current, high energy linear induction accelerators such as those of the RADLAC family. Recently they have experimentally and theoretically demonstrated that foilless diodes can be successfully coupled to self-magnetically insulated transmission line voltage adders to produce very small high brightness, high definition (no halo) electron beams. The RADLAC/SMILE experience opened the path to a new approach in high brightness, high energy induction accelerators. There is no beam drifting through the device. The voltage addition occurs in a center conductor, and the beam is created at the high voltage end in an applied magnetic field diode. This work was motivated by the remarkable success of the HERMES-III accelerator and the need to produce small radius, high energy, high current electron beams for air propagation studies and flash x-ray radiography. In this paper they present experimental results compared with analytical and numerical simulations in addition to design examples of devices that can produce multikiloamp electron beams of as high as 100 MV energies and radii as small as 1 mm

  13. A High-Voltage Level Tolerant Transistor Circuit

    NARCIS (Netherlands)

    Annema, Anne J.; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1)

  14. Advances in high voltage power switching with GTOs

    International Nuclear Information System (INIS)

    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

  15. Study of current-voltage characteristics in PbTe(Ga) alloys at low temperatures

    International Nuclear Information System (INIS)

    Akimov, B.A.; Albul, A.V.; Bogdanov, E.V.

    1992-01-01

    Results of determining current-voltage characteristics in PbTe(Ga) monocrystals of n- and p-types of conductivity in strong electric fields E ≤ 2 x 10 3 V/Cm at 4.2-77 K are presented. It was established that at helium and nitrogen temperatures, the current-voltage characteristics of PbTe(Ga) alloys, high-ohmic state of which was realized in helium, differed qualitatively from ones, typical for unalloyed PbTe. The superlinear dependence, observed in the fields, beginning from E ≥ 1 V/cm, is explained in the framework of concepts of strong electric field effect on conductivity of impurity states

  16. Connection for transfer of Liquid Nitrogen from High Voltage to ground potential

    DEFF Research Database (Denmark)

    Rasmussen, Claus Nygaard; Hansen, Finn; Willén, Dag

    2001-01-01

    In order to operate a superconducting cable conductor it must be kept at a cryogenic temperature (e.g. using liquid nitrogen). The superconducting cable conductor is at high voltage and the cooling equipment is kept at ground potential. This requires a thermally insulating connection that is also...... properties and withstand towards high-pressure liquid nitrogen. The length per joint is approximately 900 mm, including a Johnstoncoupling. The joints are tested in a closed liquid nitrogen circuit, with a pressure of up to 10 bars. The rated voltage of the cable system is 36 kV (phase-phase)....

  17. High frequency relay protection channels on super high voltage lines

    Energy Technology Data Exchange (ETDEWEB)

    Mikutskii, G V

    1964-08-01

    General aspects of high voltage transmission line design are discussed. The relationships between line voltage and length and line dimensions and power losses are explained. Electrical interference in the line is classified under three headings: interference under normal operating conditions, interference due to insulation faults, and interference due to variations in operating conditions of the high-voltage network.

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

    DEFF Research Database (Denmark)

    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...

  19. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  20. A Novel Method for In-Situ Monitoring of Local Voltage, Temperature and Humidity Distributions in Fuel Cells Using Flexible Multi-Functional Micro Sensors

    Science.gov (United States)

    Lee, Chi-Yuan; Fan, Wei-Yuan; Chang, Chih-Ping

    2011-01-01

    In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS). These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC) and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it. PMID:22319361

  1. A novel method for in-situ monitoring of local voltage, temperature and humidity distributions in fuel cells using flexible multi-functional micro sensors.

    Science.gov (United States)

    Lee, Chi-Yuan; Fan, Wei-Yuan; Chang, Chih-Ping

    2011-01-01

    In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS). These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC) and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it.

  2. A Novel Method for In-Situ Monitoring of Local Voltage, Temperature and Humidity Distributions in Fuel Cells Using Flexible Multi-Functional Micro Sensors

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chang

    2011-01-01

    Full Text Available In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS. These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it.

  3. Vivitron 1995, transient voltage simulation, high voltage insulator tests, electric field calculation

    International Nuclear Information System (INIS)

    Frick, G.; Osswald, F.; Heusch, B.

    1996-01-01

    Preliminary investigations showed clearly that, because of the discrete electrode structure of the Vivitron, important overvoltage leading to insulator damage can appear in case of a spark. The first high voltage tests showed damage connected with such events. This fact leads to a severe voltage limitation. This work describes, at first, studies made to understand the effects of transients and the associated over-voltage appearing in the Vivitron. Then we present the high voltage tests made with full size Vivitron components using the CN 6 MV machine as a pilot machine. Extensive field calculations were made. These involve simulations of static stresses and transient overvoltages, on insulating boards and electrodes. This work gave us the solutions for arrangements and modifications in the machine. After application, the Vivitron runs now without any sparks and damage at 20 MV. In the same manner, we tested column insulators of a new design and so we will find out how to get to higher voltages. Electric field calculation around the tie bars connecting the discrete electrodes together showed field enhancements when the voltages applied on the discrete electrodes are not equally distributed. This fact is one of the sources of discharges and voltage limitations. A scenario of a spark event is described and indications are given how to proceed towards higher voltages, in the 30 MV range. (orig.)

  4. A 600kV 15mA Cockcroft-Walton high-voltage power supply with high stability and low-ripple voltage

    International Nuclear Information System (INIS)

    Su Tongling; Zhang Yimin; Chen Shangwen; Liu Yantong; Lv Huiyi; Liu Jiangtao

    2006-01-01

    A Cockcroft-Walton high-voltage power supply with high stability and low-ripple voltage has been developed. This power supply has been operated in a ns pulse neutron generator. The maximum non-load voltage is 600kV while the working voltage and load current are 550kV and 15mA, respectively. The tested results indicate that when the power supply is operated at 300kV, 6.7mA and the input voltage varies +/-10%, the long-term stability of the output voltage is S=(0.300-1.006)x10 -3 . The ripple voltage is δU P-P =6.2V at 300kV, 6.8-8.3mA and the ratio of δU P-P to the output voltage V H is δU P-P /V H =2.1x10 -5

  5. High voltage electricity installations a planning perspective

    CERN Document Server

    Jay, Stephen Andrew

    2006-01-01

    The presence of high voltage power lines has provoked widespread concern for many years. High Voltage Electricity Installations presents an in-depth study of policy surrounding the planning of high voltage installations, discussing the manner in which they are percieved by the public, and the associated environmental issues. An analysis of these concerns, along with the geographical, environmental and political influences that shape their expression, is presented. Investigates local planning policy in an area of the energy sector that is of highly topical environmental and public concern Cover

  6. A High-Temperature Piezoresistive Pressure Sensor with an Integrated Signal-Conditioning Circuit

    Directory of Open Access Journals (Sweden)

    Zong Yao

    2016-06-01

    Full Text Available This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists of an encapsulated pressure-sensitive chip, a temperature compensation circuit and a signal-conditioning circuit. A silicon on insulation (SOI material and a standard MEMS process are used in the pressure-sensitive chip fabrication, and high-temperature electronic components are adopted in the temperature-compensation and signal-conditioning circuits. The entire pressure sensor achieves a hermetic seal and can be operated long-term in the range of −50 °C to 220 °C. Unlike traditional pressure sensor output voltage ranges (in the dozens to hundreds of millivolts, the output voltage of this sensor is from 0 V to 5 V, which can significantly improve the signal-to-noise ratio and measurement accuracy in practical applications of long-term transmission based on experimental verification. Furthermore, because this flexible sensor’s output voltage is adjustable, general follow-up pressure transmitter devices for voltage converters need not be used, which greatly reduces the cost of the test system. Thus, the proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments.

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

    DEFF Research Database (Denmark)

    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...

  8. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  9. Voltage generators of high voltage high power accelerators

    International Nuclear Information System (INIS)

    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. Physicochemical assessment criteria for high-voltage pulse capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Darian, L. A., E-mail: LDarian@rambler.ru; Lam, L. Kh. [National Research University, Moscow Power Engineering Institute (Russian Federation)

    2016-12-15

    In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.

  11. Physicochemical assessment criteria for high-voltage pulse capacitors

    International Nuclear Information System (INIS)

    Darian, L. A.; Lam, L. Kh.

    2016-01-01

    In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.

  12. Time isolation high-voltage impulse generator

    International Nuclear Information System (INIS)

    Chodorow, A.M.

    1975-01-01

    Lewis' high-voltage impulse generator is analyzed in greater detail, demonstrating that voltage between adjacent nodes can be equalized by proper selection of parasitic impedances. This permits improved TEM mode propagation to a matched load, with more faithful source waveform preservation

  13. Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

    Science.gov (United States)

    Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

    2016-07-22

    The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

  14. Detecting Faults In High-Voltage Transformers

    Science.gov (United States)

    Blow, Raymond K.

    1988-01-01

    Simple fixture quickly shows whether high-voltage transformer has excessive voids in dielectric materials and whether high-voltage lead wires too close to transformer case. Fixture is "go/no-go" indicator; corona appears if transformer contains such faults. Nests in wire mesh supported by cap of clear epoxy. If transformer has defects, blue glow of corona appears in mesh and is seen through cap.

  15. Nested high voltage generator/particle accelerator

    International Nuclear Information System (INIS)

    Adler, R.J.

    1992-01-01

    This patent describes a modular high voltage particle accelerator having an emission axis and an emission end, the accelerator. It comprises: a plurality of high voltage generators in nested adjacency to form a nested stack, each the generator comprising a cup-like housing having a base and a tubular sleeve extending from the base, a primary transformer winding encircling the nested stack; a secondary transformer winding between each adjacent pair of housings, magnetically linked to the primary transformer winding through the gaps; a power supply respective to each of the secondary windings converting alternating voltage from its respective secondary winding to d.c. voltage, the housings at the emission end forming a hollow throat for particle acceleration, a vacuum seal at the emission end of the throat which enables the throat to be evacuated; a particle source in the thrond power means to energize the primary transformer winding

  16. Discussion - a high voltage DC generator

    International Nuclear Information System (INIS)

    Bhagwat, P.V.; Singh, Jagir; Hattangadi, V.A.

    1993-01-01

    One of the requirements for a high power ion source is a high voltage, high current DC generator. The high voltage, high current generator, DISCATRON, presently under development in our laboratory is a rotating disc type electrostatic generator similar in design to the one reported by A. Isoya et al. (1985). It is compact and rugged electrostatic DC generator based on the principle of induction charging by pellet chains used in the pelletron accelerator. It is, basically, a constant-current device with little stored energy, so that, in case of a breakdown, damage to the equipment connected to the output terminals is minimal. Since the present generator is only a proto-type, meant for a study of the practical difficulties that would be encountered in its manufacture, the output voltage and current specified has been kept quite modest viz., 300 kV at 500 μA, maximum. Some results of the preliminary tests carried out with this generator are described. (author). 4 figs

  17. High Voltage in Noble Liquids for High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Rebel, B. [Fermilab; Bernard, E. [Yale U.; Faham, C. H. [LBL, Berkeley; Ito, T. M. [Los Alamos; Lundberg, B. [Maryland U.; Messina, M. [Columbia U.; Monrabal, F. [Valencia U., IFIC; Pereverzev, S. P. [LLNL, Livermore; Resnati, F. [Zurich, ETH; Rowson, P. C. [SLAC; Soderberg, M. [Fermilab; Strauss, T. [Bern U.; Tomas, A. [Imperial Coll., London; Va' vra, J. [SLAC; Wang, H. [UCLA

    2014-08-22

    A workshop was held at Fermilab November 8-9, 2013 to discuss the challenges of using high voltage in noble liquids. The participants spanned the fields of neutrino, dark matter, and electric dipole moment physics. All presentations at the workshop were made in plenary sessions. This document summarizes the experiences and lessons learned from experiments in these fields at developing high voltage systems in noble liquids.

  18. High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    Science.gov (United States)

    Shimer, Daniel W.; Lange, Arnold C.

    1995-01-01

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  19. High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    Science.gov (United States)

    Shimer, D.W.; Lange, A.C.

    1995-05-23

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

  20. Low power consumption and high temperature durability for radiation sensor

    International Nuclear Information System (INIS)

    Matsumoto, Yoshinori; Ueno, Hiroto

    2015-01-01

    Low power consumption and high temperature operation are important in an environmental monitoring system. The power consumption of 3 mW is achieved for the radiation sensor using low voltage operational amplifier and comparator in the signal processing circuit. The leakage reverse current of photodiode causes the charge amplifier saturation over 50degC. High temperature durability was improved by optimizing the circuit configuration and the values of feedback resistance and capacitance in the charge amplifier. The pulse response of the radiation sensor was measured up to 55degC. The custom detection circuit was designed by 0.6 μm CMOS process at 5-V supply voltage. The operation temperature was improved up to 65degC. (author)

  1. Unfolding of a Temperature-Sensitive Domain Controls Voltage-Gated Channel Activation.

    Science.gov (United States)

    Arrigoni, Cristina; Rohaim, Ahmed; Shaya, David; Findeisen, Felix; Stein, Richard A; Nurva, Shailika Reddy; Mishra, Smriti; Mchaourab, Hassane S; Minor, Daniel L

    2016-02-25

    Voltage-gated ion channels (VGICs) are outfitted with diverse cytoplasmic domains that impact function. To examine how such elements may affect VGIC behavior, we addressed how the bacterial voltage-gated sodium channel (BacNa(V)) C-terminal cytoplasmic domain (CTD) affects function. Our studies show that the BacNa(V) CTD exerts a profound influence on gating through a temperature-dependent unfolding transition in a discrete cytoplasmic domain, the neck domain, proximal to the pore. Structural and functional studies establish that the BacNa(V) CTD comprises a bi-partite four-helix bundle that bears an unusual hydrophilic core whose integrity is central to the unfolding mechanism and that couples directly to the channel activation gate. Together, our findings define a general principle for how the widespread four-helix bundle cytoplasmic domain architecture can control VGIC responses, uncover a mechanism underlying the diverse BacNa(V) voltage dependencies, and demonstrate that a discrete domain can encode the temperature-dependent response of a channel. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. High voltage pulse generator. [Patent application

    Science.gov (United States)

    Fasching, G.E.

    1975-06-12

    An improved high-voltage pulse generator is described which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of the first rectifier connected between the first and second capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. The output voltage can be readily increased by adding additional charging networks. The circuit allows the peak level of the output to be easily varied over a wide range by using a variable autotransformer in the charging circuit.

  3. Trap Healing for High-Performance Low-Voltage Polymer Transistors and Solution-Based Analog Amplifiers on Foil.

    Science.gov (United States)

    Pecunia, Vincenzo; Nikolka, Mark; Sou, Antony; Nasrallah, Iyad; Amin, Atefeh Y; McCulloch, Iain; Sirringhaus, Henning

    2017-06-01

    Solution-processed semiconductors such as conjugated polymers have great potential in large-area electronics. While extremely appealing due to their low-temperature and high-throughput deposition methods, their integration in high-performance circuits has been difficult. An important remaining challenge is the achievement of low-voltage circuit operation. The present study focuses on state-of-the-art polymer thin-film transistors based on poly(indacenodithiophene-benzothiadiazole) and shows that the general paradigm for low-voltage operation via an enhanced gate-to-channel capacitive coupling is unable to deliver high-performance device behavior. The order-of-magnitude longitudinal-field reduction demanded by low-voltage operation plays a fundamental role, enabling bulk trapping and leading to compromised contact properties. A trap-reduction technique based on small molecule additives, however, is capable of overcoming this effect, allowing low-voltage high-mobility operation. This approach is readily applicable to low-voltage circuit integration, as this work exemplifies by demonstrating high-performance analog differential amplifiers operating at a battery-compatible power supply voltage of 5 V with power dissipation of 11 µW, and attaining a voltage gain above 60 dB at a power supply voltage below 8 V. These findings constitute an important milestone in realizing low-voltage polymer transistors for solution-based analog electronics that meets performance and power-dissipation requirements for a range of battery-powered smart-sensing applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge

    International Nuclear Information System (INIS)

    Ponomarev, A V; Pedos, M S; Scherbinin, S V; Mamontov, Y I; Ponomarev, S V

    2015-01-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface. (paper)

  5. 76 FR 72203 - Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda

    Science.gov (United States)

    2011-11-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD12-5-000] Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda As announced in the Notice of Staff..., from 9 a.m. to 4:30 p.m. to explore the interaction between voltage control, reliability, and economic...

  6. High Voltage Homemade Capacitor Charger for Plasma Focus System

    International Nuclear Information System (INIS)

    Abdul Halim Baijan; Azaman Ahmad; Rokiah Mohd Sabri; Siti Aiasah Hashim; Mohd Rizal Md Chulan; Wah, L.K.; Azhar Ahmad; Rosli Che Ros; Mohd Faiz Mohd Zin

    2015-01-01

    A high voltage capacitor charger has been designed and built to replace a high voltage charger type General Atomics CCDs Power Supply which was damaged. The fabrication design was using materials which were easily available in the local market. Among the main components of the high-voltage charger is a transformer for neon lights, variable transformer rated 0 - 240 V 1 KVA, and 240 V transformer isolator. The results of experiments that have been conducted shows that a homemade capacitor charger was able to charge high voltage capacitors up to the required voltage of which was 12 kV. However the time taken for charging is quite long, up to more than 6 minutes. (author)

  7. 30 CFR 77.704-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 77.704-1 Section 77... MINES Grounding § 77.704-1 Work on high-voltage lines. (a) No high-voltage line shall be regarded as... provided in § 77.103) that such high-voltage line has been deenergized and grounded. Such qualified person...

  8. Temperature Dependences of Torque Generation and Membrane Voltage in the Bacterial Flagellar Motor

    Science.gov (United States)

    Inoue, Yuichi; Baker, Matthew A.B.; Fukuoka, Hajime; Takahashi, Hiroto; Berry, Richard M.; Ishijima, Akihiko

    2013-01-01

    In their natural habitats bacteria are frequently exposed to sudden changes in temperature that have been shown to affect their swimming. With our believed to be new methods of rapid temperature control for single-molecule microscopy, we measured here the thermal response of the Na+-driven chimeric motor expressed in Escherichia coli cells. Motor torque at low load (0.35 μm bead) increased linearly with temperature, twofold between 15°C and 40°C, and torque at high load (1.0 μm bead) was independent of temperature, as reported for the H+-driven motor. Single cell membrane voltages were measured by fluorescence imaging and these were almost constant (∼120 mV) over the same temperature range. When the motor was heated above 40°C for 1–2 min the torque at high load dropped reversibly, recovering upon cooling below 40°C. This response was repeatable over as many as 10 heating cycles. Both increases and decreases in torque showed stepwise torque changes with unitary size ∼150 pN nm, close to the torque of a single stator at room temperature (∼180 pN nm), indicating that dynamic stator dissociation occurs at high temperature, with rebinding upon cooling. Our results suggest that the temperature-dependent assembly of stators is a general feature of flagellar motors. PMID:24359752

  9. Novel Interleaved Converter with Extra-High Voltage Gain to Process Low-Voltage Renewable-Energy Generation

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2016-10-01

    Full Text Available This paper presents a novel interleaved converter (NIC with extra-high voltage gain to process the power of low-voltage renewable-energy generators such as photovoltaic (PV panel, wind turbine, and fuel cells. The NIC can boost a low input voltage to a much higher voltage level to inject renewable energy to DC bus for grid applications. Since the NIC has two circuit branches in parallel at frond end to share input current, it is suitable for high power applications. In addition, the NIC is controlled in an interleaving pattern, which has the advantages that the NIC has lower input current ripple, and the frequency of the ripple is twice the switching frequency. Two coupled inductors and two switched capacitors are incorporated to achieve a much higher voltage gain than conventional high step-up converters. The proposed NIC has intrinsic features such as leakage energy totally recycling and low voltage stress on power semiconductor. Thorough theoretical analysis and key parameter design are presented in this paper. A prototype is built for practical measurements to validate the proposed NIC.

  10. Evaluation of deterioration of insulators in high-voltage motors by partial discharge

    International Nuclear Information System (INIS)

    Mikami, Masao

    2003-01-01

    For the purpose of early detection of deterioration of insulators in high-voltage motors which are widely utilized in nuclear power stations, a new type on-line partial discharge monitor developed at INSS was applied to test the deterioration of about 150 sets of high-voltage motors running in nuclear power stations practically. From the results, it is shown that (1) tendency of the deterioration can be obtained by this method in general, (2) the magnitude of the on-line partial discharge hardly correlates with that of off-line measurement, but depends on temperature and other environmental conditions, and (3) by observing phase characteristics of partial discharge, it is possible to make a diagnosis of phase-to-phase tracking in end-winding coils of a stator. (author)

  11. Nonequilibrium segregation and phase instability in alloy films during elevated-temperature irradiation in a high-voltage electron microscope

    Science.gov (United States)

    Lam, N. Q.; Okamoto, P. R.

    1984-05-01

    The effects of defect-production rate gradients, caused by the radial nonuniformity in the electron flux distribution, on solute segregation and phase stability in alloy films undergoing high-voltage electron-microscope (HVEM) irradiation at high temperatures are assessed. Two-dimensional (axially symmetric) compositional redistributions were calculated, taking into account both axial and transverse radial defect fluxes. It was found that when highly focused beams were employed radiation-induced segregation consisted of two stages: dominant axial segregation at the film surfaces at short irradiation times and competitive radial segregation at longer times. The average alloy composition within the irradiated region could differ greatly from that irradiated with a uniform beam, because of the additional atom transport from or to the region surrounding the irradiated zone under the influence of radial fluxes. Damage-rate gradient effects must be taken into account when interpreting in-situ HVEM observations of segregation-induced phase instabilities. The theoretical predictions are compared with experimental observations of the temporal and spatial dependence of segregation-induced precipitation in thin films of Ni-Al, Ni-Ge and Ni-Si solid solutions.

  12. Complete low power controller for high voltage power systems

    International Nuclear Information System (INIS)

    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

  13. E-beam high voltage switching power supply

    Science.gov (United States)

    Shimer, Daniel W.; Lange, Arnold C.

    1997-01-01

    A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

  14. E-beam high voltage switching power supply

    International Nuclear Information System (INIS)

    Shimer, D.W.; Lange, A.C.

    1997-01-01

    A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360 degree/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs

  15. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    Rocca, J.J.; Szapiro, B.; Murray, C.

    1989-01-01

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  16. High voltage generator circuit with low power and high efficiency applied in EEPROM

    International Nuclear Information System (INIS)

    Liu Yan; Zhang Shilin; Zhao Yiqiang

    2012-01-01

    This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM). The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique. The high efficiency is dependent on the zero threshold voltage (V th ) MOSFET and the charge transfer switch (CTS) charge pump. The proposed high voltage generator circuit has been implemented in a 0.35 μm EEPROM CMOS process. Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits. This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation. (semiconductor integrated circuits)

  17. Suppression of the high-frequency disturbances in low-voltage circuits caused by disconnector operation in high-voltage open-air substations

    Energy Technology Data Exchange (ETDEWEB)

    Savic, M.S.

    1986-07-01

    The switching off and on of small capacitive currents charging busbar capacitances, connection conductors and open circuit breakers with disconnectors causes high-frequency transients in high-voltage networks. In low voltage circuits, these transient processes induce dangerous overvoltages for the electronic equipment in the substation. A modified construction of the disconnector with a damping resistor was investigated. Digital simulation of the transient process in a high-voltage network during the arcing period between the disconnector contacts with and without damping resistor were performed. A significant decrease of the arcing duration and the decrease of the electromagnetic field magnitude in the vicinity of the operating disconnector were noticed. In the low voltage circuit protected with the surge arrester, the overvoltage magnitude was not affected by the damping resistor due to the arrester protection effect.

  18. Experimental validation of prototype high voltage bushing

    Science.gov (United States)

    Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.

    2017-08-01

    Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

  19. 30 CFR 75.811 - High-voltage underground equipment; grounding.

    Science.gov (United States)

    2010-07-01

    ...-voltage equipment supplying power to such equipment receiving power from resistance grounded systems shall... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage underground equipment; grounding... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage...

  20. High-voltage nanosecond pulse shaper

    International Nuclear Information System (INIS)

    Kapishnikov, N.K.; Muratov, V.M.; Shatanov, A.A.

    1987-01-01

    A high-voltage pulse shaper with an output of up to 250 kV, a base duration of ∼ 10 nsec, and a repetition frequency of 50 pulses/sec is described. The described high-voltage nanosecond pulse shaper is designed for one-orbit extraction of an electron beam from a betatron. A diagram of the pulse shaper, which employs a single-stage generator is shown. The shaping element is a low-inductance capacitor bank of series-parallel KVI-3 (2200 pF at 10 kV) or K15-10 (4700 pF at 31.5 kV) disk ceramic capacitors. Four capacitors are connected in parallel and up to 25 are connected in series

  1. Evaluation of the high-voltage high-frequency transformer insulating materials for satellites

    International Nuclear Information System (INIS)

    Kurita, Hiroshi; Hasegawa, Taketoshi; Hirasawa, Eiichi; Gonai, Toshio; Ohsuga, Hiroyuki.

    1987-01-01

    Environment resistance evaluation was made of the insulating materials of impregnated injection type for high-voltage high-frequency transformers mounted in satellites. (1) The stress occurring in the impregnated injection type resin is small in silicon resin and urethane resin and large in epoxy resin. (2) The dielectric characteristic at high frequency is good in silicone resin. In epoxy resin, when the transformer is operated at high temperature, its thermal runaway may take place. (3) The radiation deterioration at 1 Mrad - 10 Mrad is slight in urethane resin. (4) The degassing is not good in silicone resin. (5) The adhesive power is good in urethane resin. (6) From the above results, in silicone resin there is problem in degassing and adhesive power. In epoxy resin there is problem in stress and dielectric characteristic. (Mori, K.)

  2. High voltage performance of BARC-TIFR Pelletron Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Surendran, P.; Ansari, Q.N.; Nair, J.P., E-mail: surendra@tifr.res.in [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai (India); and others

    2014-07-01

    The 14 UD Pelletron Accelerator at TIFR, Mumbai is operational since its inception in 1988. It was decided to impart enough time for high voltage conditioning to achieve higher operational voltage. Prior to this, comprehensive works such as replacing all the sputter ion pumps and Titanium sublimation pumps across the accelerator tube with new or refurbished ones and replacement of Alumina balls in the SF{sub 6} drier with fresh balls were carried out. High voltage conditioning of each module was done. Further conditioning of two modules at a time in overlapping mode improved the terminal voltage. As a result of this rigorous conditioning Terminal voltage of 12.6 MV was achieved and beam has been delivered to users at 12 MV terminal. Details of this effort will be presented in this paper. (author)

  3. High voltage performance of BARC-TIFR Pelletron Accelerator

    International Nuclear Information System (INIS)

    Surendran, P.; Ansari, Q.N.; Nair, J.P.

    2014-01-01

    The 14 UD Pelletron Accelerator at TIFR, Mumbai is operational since its inception in 1988. It was decided to impart enough time for high voltage conditioning to achieve higher operational voltage. Prior to this, comprehensive works such as replacing all the sputter ion pumps and Titanium sublimation pumps across the accelerator tube with new or refurbished ones and replacement of Alumina balls in the SF_6 drier with fresh balls were carried out. High voltage conditioning of each module was done. Further conditioning of two modules at a time in overlapping mode improved the terminal voltage. As a result of this rigorous conditioning Terminal voltage of 12.6 MV was achieved and beam has been delivered to users at 12 MV terminal. Details of this effort will be presented in this paper. (author)

  4. PV source based high voltage gain current fed converter

    Science.gov (United States)

    Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

    2017-11-01

    This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

  5. Sheath and arc-column voltages in high-pressure arc discharges

    International Nuclear Information System (INIS)

    Benilov, M S; Benilova, L G; Li Heping; Wu Guiqing

    2012-01-01

    Electrical characteristics of a 1 cm-long free-burning atmospheric-pressure argon arc are calculated by means of a model taking into account the existence of a near-cathode space-charge sheath and the discrepancy between the electron and heavy-particle temperatures in the arc column. The computed arc voltage exhibits a variation with the arc current I similar to the one revealed by the experiment and exceeds experimental values by no more than approximately 2 V in the current range 20-175 A. The sheath contributes about two-thirds or more of the arc voltage. The LTE model predicts a different variation of the arc voltage with I and underestimates the experimental values appreciably for low currents but by no more than approximately 2 V for I ≳ 120 A. However, the latter can hardly be considered as a proof of unimportance of the space-charge sheath at high currents: the LTE model overestimates both the resistance of the bulk of the arc column and the resistance of the part of the column that is adjacent to the cathode, and this overestimation to a certain extent compensates for the neglect of the voltage drop in the sheath. Furthermore, if the latter resistance were evaluated in the framework of the LTE model in an accurate way, then the overestimation would be still much stronger and the obtained voltage would significantly exceed those observed in the experiment.

  6. An Improvement on the Junction Temperature Measurement of Light-Emitting Diodes by using the Peak Shift Method Compared with the Forward Voltage Method

    International Nuclear Information System (INIS)

    He Su-Ming; Wang Jin-Bin; Luo Xiang-Dong; Zhang Bo; Fu Lei; Cheng Li-Wen; Lu Wei

    2012-01-01

    The junction temperature of red, green and blue high power light emitting diodes (LEDs) is measured by using the emission peak shift method and the forward voltage method. Both the emission peak shift and the forward voltage decrease show a linear relationship relative to junction temperature. The linear coefficients of the red, green and blue LEDs for the peak shift method and the forward voltage method range from 0.03 to 0.15 nm/°C and from 1.33 to 3.59 mV/°C, respectively. Compared with the forward voltage method, the peak shift method is almost independent of bias current and sample difference. The variation of the slopes is less than 2% for the peak shift method and larger than 30% for the forward voltage method, when the LEDs are driven by different bias currents. It is indicated that the peak shift method gives better stability than the forward voltage method under different LED working conditions

  7. 30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

    Science.gov (United States)

    2010-07-01

    ... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables; minimum design...

  8. The high voltage homopolar generator

    Science.gov (United States)

    Price, J. H.; Gully, J. H.; Driga, M. D.

    1986-11-01

    System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

  9. Voltage Balancing Method on Expert System for 51-Level MMC in High Voltage Direct Current Transmission

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2016-01-01

    Full Text Available The Modular Multilevel Converters (MMC have been a spotlight for the high voltage and high power transmission systems. In the VSC-HVDC (High Voltage Direct Current based on Voltage Source Converter transmission system, the energy of DC link is stored in the distributed capacitors, and the difference of capacitors in parameters and charge rates causes capacitor voltage balance which affects the safety and stability of HVDC system. A method of MMC based on the expert system for reducing the frequency of the submodules (SMs of the IGBT switching frequency is proposed. Firstly, MMC with 51 levels for HVDC is designed. Secondly, the nearest level control (NLC for 51-level MMC is introduced. Thirdly, a modified capacitor voltage balancing method based on expert system for MMC-based HVDC transmission system is proposed. Finally, a simulation platform for 51-level Modular Multilevel Converter is constructed by using MATLAB/SIMULINK. The results indicate that the strategy proposed reduces the switching frequency on the premise of keeping submodule voltage basically identical, which greatly reduces the power losses for MMC-HVDC system.

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

    International Nuclear Information System (INIS)

    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.

  11. High voltage capacitor design and the determination of solid dielectric voltage breakdown

    International Nuclear Information System (INIS)

    Hutapea, S.

    1976-01-01

    The value of the external field intensity serves as an electrical insulating material and is a physical characteristic of the substance. Capacitor discharge in the dielectric medium are experimentally investigated. The high voltage power supply and other instrument needed are briefly discussed. Capacitors with working voltage of 30.000 volt and the plastic being used for dielectrics in the capacitors are also discussed. (author)

  12. System for improving measurement accuracy of transducer by measuring transducer temperature and resistance change using thermoelectric voltages

    Science.gov (United States)

    Anderson, Karl F. (Inventor); Parker, Allen R., Jr. (Inventor)

    1993-01-01

    A constant current loop measuring system measures a property including the temperature of a sensor responsive to an external condition being measured. The measuring system includes thermocouple conductors connected to the sensor, sensing first and second induced voltages responsive to the external condition. In addition, the measuring system includes a current generator and reverser generating a constant current, and supplying the constant current to the thermocouple conductors in forward and reverse directions generating first and second measured voltages, and a determining unit receiving the first and second measured voltages from the current generator and reverser, and determining the temperature of the sensor responsive to the first and second measured voltages.

  13. Capacitance–voltage and current–voltage characteristics for the study of high background doping and conduction mechanisms in GaAsN grown by chemical beam epitaxy

    International Nuclear Information System (INIS)

    Bouzazi, Boussairi; Kojima, Nobuaki; Ohshita, Yoshio; Yamaguchi, Masafumi

    2013-01-01

    Highlights: ► The cause of high background doping was confirmed and characterized. ► The current–voltage characteristics deviate from the thermionic emission. ► The recombination current is attributed to a hole trap (E V + 0.52 eV). ► The hole trap (E V + 0.52 eV) was confirmed by DLTS measurements. -- Abstract: The temperature dependence of capacitance–voltage (C–V) and current voltage (I–V) characteristics were used to study the cause of high background doping and the underlying current transport mechanisms in GaAsN Schottky diode grown by chemical beam epitaxy (CBE). In one hand, a nitrogen-related sigmoid increase of junction capacitance and ionized acceptor concentration was observed in the temperature range 70–100 K and was attributed to the thermal ionization of a nitrogen–hydrogen-related deep acceptor-state, with thermal activation energy of approximately 0.11 eV above the valence band maximum (VBM) of GaAsN. This acceptor state is mainly responsible for the high background doping in unintentionally doped GaAsN grown by CBE. On the other hand, the I–V characteristics at different temperatures were found to deviate from the well known pure thermionic-emission mechanism. Based on their fitting at each temperature, the recombination current in the space charge region of GaAsN Schottky diode was mainly attributed to a hole trap, localized at 0.51 eV above the VBM. Given the accuracy of measurements, this result was confirmed by deep level transient spectroscopy measurements. Nevertheless, considering the Shockley–Read–Hall model of generation-recombination, the recombination activity of this defect was quantified and qualified to be weak compared with the markedly degradation of minority carrier lifetime in GaAsN material

  14. Nonequilibrium segregation and phase instability in alloy films during elevated-temperature irradiation in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Lam, N.Q.; Okamoto, P.R.

    1984-05-01

    The effects of defect-production rate gradients, caused by the radial nonuniformity in the electron flux distribution, on solute segregation and phase stability in alloy films undergoing high-voltage electron-microscope (HVEM) irradiation at high temperatures are assessed. Two-dimensional (axially symmetric) compositional redistributions were calculated, taking into account both axial and transverse radial defect fluxes. It was found that when highly focused beams were employed radiation-induced segregation consisted of two stages: dominant axial segregation at the film surfaces at short irradiation times and competitive radial segregation at longer times. The average alloy composition within the irradiated region could differ greatly from that irradiated with a uniform beam, because of the additional atom transport from or to the region surrounding the irradiated zone under the influence of radial fluxes. As a result, damage-rate gradient effects must be taken into account when interpreting in-situ HVEM observations of segregation-induced phase instabilities. The theoretical predictions are compared with experimental observations of the temporal and spatial dependence of segregation-induced precipitation in thin films of Ni-Al, Ni-Ge and Ni-Si solid solutions

  15. 30 CFR 77.807-1 - High-voltage powerlines; clearances above ground.

    Science.gov (United States)

    2010-07-01

    ... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-1 High-voltage powerlines; clearances above ground. High-voltage powerlines located above driveways, haulageways, and railroad tracks...

  16. Design and Implementation of a High Efficiency, Low Component Voltage Stress, Single-Switch High Step-Up Voltage Converter for Vehicular Green Energy Systems

    Directory of Open Access Journals (Sweden)

    Yu-En Wu

    2016-09-01

    Full Text Available In this study, a novel, non-isolated, cascade-type, single-switch, high step-up DC/DC converter was developed for green energy systems. An integrated coupled inductor and voltage lift circuit were applied to simplify the converter structure and satisfy the requirements of high efficiency and high voltage gain ratios. In addition, the proposed structure is controllable with a single switch, which effectively reduces the circuit cost and simplifies the control circuit. With the leakage inductor energy recovery function and active voltage clamp characteristics being present, the circuit yields optimizable conversion efficiency and low component voltage stress. After the operating principles of the proposed structure and characteristics of a steady-state circuit were analyzed, a converter prototype with 450 W, 40 V of input voltage, 400 V of output voltage, and 95% operating efficiency was fabricated. The Renesas MCU RX62T was employed to control the circuits. Experimental results were analyzed to validate the feasibility and effectiveness of the proposed system.

  17. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  18. Design and Implementation of a High-Voltage Generator with Output Voltage Control for Vehicle ER Shock-Absorber Applications

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A self-oscillating high-voltage generator is proposed to supply voltage for a suspension system in order to control the damping force of an electrorheological (ER fluid shock absorber. By controlling the output voltage level of the generator, the damping force in the ER fluid shock absorber can be adjusted immediately. The shock absorber is part of the suspension system. The high-voltage generator drives a power transistor based on self-excited oscillation, which converts dc to ac. A high-frequency transformer with high turns ratio is used to increase the voltage. In addition, the system uses the car battery as dc power supply. By regulating the duty cycle of the main switch in the buck converter, the output voltage of the buck converter can be linearly adjusted so as to obtain a specific high voltage for ER. The driving system is self-excited; that is, no additional external driving circuit is required. Thus, it reduces cost and simplifies system structure. A prototype version of the actual product is studied to measure and evaluate the key waveforms. The feasibility of the proposed system is verified based on experimental results.

  19. In-situ monitoring of internal local temperature and voltage of proton exchange membrane fuel cells.

    Science.gov (United States)

    Lee, Chi-Yuan; Fan, Wei-Yuan; Hsieh, Wei-Jung

    2010-01-01

    The distribution of temperature and voltage of a fuel cell are key factors that influence performance. Conventional sensors are normally large, and are also useful only for making external measurements of fuel cells. Centimeter-scale sensors for making invasive measurements are frequently unable to accurately measure the interior changes of a fuel cell. This work focuses mainly on fabricating flexible multi-functional microsensors (for temperature and voltage) to measure variations in the local temperature and voltage of proton exchange membrane fuel cells (PEMFC) that are based on micro-electro-mechanical systems (MEMS). The power density at 0.5 V without a sensor is 450 mW/cm(2), and that with a sensor is 426 mW/cm(2). Since the reaction area of a fuel cell with a sensor is approximately 12% smaller than that without a sensor, but the performance of the former is only 5% worse.

  20. IBM-PC based high voltage controller [Paper No.: L7

    International Nuclear Information System (INIS)

    Mondal, N.K.; Kalmani, S.D.

    1993-01-01

    A simple IBM-PC/XT based high voltage controller is designed for C.A.E.N. high voltage supply unit, which is being used for testing the prototype detector for future accelerator experiment. The high voltage output of the supply unit can be remotely programmed. The V-set Lemo connectors at the rear panel provides the remote control facility. Similarly V-mon and I-mon can be used for remotely monitoring the voltage set and the current drawn from the supply unit. The controller described here sets the high voltage through V-set and monitors the voltage set, through V-mon at a pre-determined time interval. The monitoring is a background job and is done as an interrupt service routine of IRQ3. A simple menu driven software package used is written in Q-Basic and MASM. (author). 1 fig

  1. Optical control system for high-voltage terminals

    International Nuclear Information System (INIS)

    Bicek, J.J.

    1978-01-01

    An optical control system for the control of devices in the terminal of an electrostatic accelerator includes a laser that is modulated by a series of preselected codes produced by an encoder. A photodiode receiver is placed in the laser beam at the high-voltage terminal of an electrostatic accelerator. A decoder connected to the photodiode decodes the signals to provide control impulses for a plurality of devices at the high voltage of the terminal

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

    International Nuclear Information System (INIS)

    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

  3. 21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

  4. 30 CFR 75.705-1 - Work on high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines. 75.705-1 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.705-1 Work on high-voltage lines. (a) Section 75.705 specifically prohibits work on energized high-voltage lines underground; (b...

  5. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.; Abdelghany, Mohamed A.; Elsayed, Mohannad Yomn; Elshurafa, Amro M; Salama, Khaled N.

    2014-01-01

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  6. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  7. Mitigating voltage lead errors of an AC Josephson voltage standard by impedance matching

    Science.gov (United States)

    Zhao, Dongsheng; van den Brom, Helko E.; Houtzager, Ernest

    2017-09-01

    A pulse-driven AC Josephson voltage standard (ACJVS) generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test (DUT) at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. Error correction mechanisms investigated so far allow the ACJVS to be operational for frequencies up to 100 kHz. In this paper, calculations are presented to deal with these errors in terms of reflected waves. Impedance matching at the source side of the system, which is loaded with a high-impedance DUT, is proposed as an accurate method to mitigate these errors for frequencies up to 1 MHz. Simulations show that the influence of non-ideal component characteristics, such as the tolerance of the matching resistor, the capacitance of the load input impedance, losses in the voltage leads, non-homogeneity in the voltage leads, a non-ideal on-chip connection and inductors between the Josephson junction array and the voltage leads, can be corrected for using the proposed procedures. The results show that an expanded uncertainty of 12 parts in 106 (k  =  2) at 1 MHz and 0.5 part in 106 (k  =  2) at 100 kHz is within reach.

  8. Semi-empirical model for the threshold voltage of a double implanted MOSFET and its temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Arora, N D

    1987-05-01

    A simple and accurate semi-empirical model for the threshold voltage of a small geometry double implanted enhancement type MOSFET, especially useful in a circuit simulation program like SPICE, has been developed. The effect of short channel length and narrow width on the threshold voltage has been taken into account through a geometrical approximation, which involves parameters whose values can be determined from the curve fitting experimental data. A model for the temperature dependence of the threshold voltage for the implanted devices has also been presented. The temperature coefficient of the threshold voltage was found to change with decreasing channel length and width. Experimental results from various device sizes, both short and narrow, show very good agreement with the model. The model has been implemented in SPICE as part of the complete dc model.

  9. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Thermophysical and radiation properties of high-temperature C4F8-CO2 mixtures to replace SF6 in high-voltage circuit breakers

    Science.gov (United States)

    Zhong, Linlin; Cressault, Yann; Teulet, Philippe

    2018-03-01

    C4F8-CO2 mixtures are one of the potential substitutes to SF6 in high-voltage circuit breakers. However, the arc quenching ability of C4F8-CO2 mixtures is still unknown. In order to provide the necessary basic data for the further investigation of arc quenching performance, the compositions, thermodynamic properties, transport coefficients, and net emission coefficients (NEC) of various C4F8-CO2 mixtures are calculated at temperatures of 300-30 000 K in this work. The thermodynamic properties are presented as the product of mass density and specific heat, i.e., ρCp. The transport coefficients include electrical conductivity, viscosity, and thermal conductivity. The atomic and molecular radiation are both taken into account in the calculation of NEC. The comparison of the properties between SF6 and C4F8-CO2 mixtures is also discussed to find their differences. The results of compositions show that C4F8-CO2 mixtures have a distinctive advantage over other alternative gases e.g., CF3I and C3F8, because the dissociative product (i.e., C4F6) of C4F8 at low temperatures has a very high dielectric strength. This is good for an arc quenching medium to endure the arc recovery phase. Compared with SF6, C4F8-CO2 mixtures present lower ρCp at temperatures below 2800 K and larger thermal conductivity above 2800 K. Based on the position of peaks in thermal conductivity, we predict that the cooling of C4F8-CO2 arc will be slowed down at higher temperatures than that of SF6 arc. It is also found that the mixing of CO2 shows slight effects on the electrical conductivity and NEC of C4F8-CO2 mixtures.

  11. A compact 100 kV high voltage glycol capacitor.

    Science.gov (United States)

    Wang, Langning; Liu, Jinliang; Feng, Jiahuai

    2015-01-01

    A high voltage capacitor is described in this paper. The capacitor uses glycerol as energy storage medium, has a large capacitance close to 1 nF, can hold off voltages of up to 100 kV for μs charging time. Allowing for low inductance, the capacitor electrode is designed as coaxial structure, which is different from the common structure of the ceramic capacitor. With a steady capacitance at different frequencies and a high hold-off voltage of up to 100 kV, the glycol capacitor design provides a potential substitute for the ceramic capacitors in pulse-forming network modulator to generate high voltage pulses with a width longer than 100 ns.

  12. Application of transducers to the control of temperatures and of alternating and direct voltages (1962)

    International Nuclear Information System (INIS)

    Raoult, N.

    1960-11-01

    The temperature regulator and the voltage regulators described have been studied with a view to conferring a high degree of safety to the apparatuses in which they are used. They make use almost exclusively of Transducers which are passive elements acting mainly in these apparatuses as amplifiers and which are entirely satisfactory, ensuring that the regulators studied keep their essential qualities i.e accuracy, reliability, stability and sensitivity. (author) [fr

  13. Transmission of power at high voltages

    Energy Technology Data Exchange (ETDEWEB)

    Lane, F J

    1963-01-01

    High voltage transmission is considered to be concerned with circuits and systems operating at or above 132 kV. While the general examination is concerned with ac transmission, dc systems are also included. The choice of voltage for a system will usually involve hazardous assessments of the future requirements of industry, commerce and a changing population. Experience suggests that, if the estimated economic difference between two voltages is not significant, there is good reason to choose the higher voltage, as this will make the better provision for unexpected future expansion. Two principal functions served by transmission circuits in a supply system are: (a) the transportation of energy in bulk from the generator to the reception point in the distribution system; and (b) the interconnection and integration of the generating plant and associated loads. These functions are considered and various types of system are discussed in terms of practicability, viability, quality and continuity of supply. Future developments requiring transmission voltages up to 750 kV will raise many problems which are in the main empirical. Examples are given of the type of problem envisaged and it is suggested that these can only be partially solved by theory and model operation.

  14. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than 15,000...

  15. In-situ Monitoring of Internal Local Temperature and Voltage of Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2010-06-01

    Full Text Available The distribution of temperature and voltage of a fuel cell are key factors that influence performance. Conventional sensors are normally large, and are also useful only for making external measurements of fuel cells. Centimeter-scale sensors for making invasive measurements are frequently unable to accurately measure the interior changes of a fuel cell. This work focuses mainly on fabricating flexible multi-functional microsensors (for temperature and voltage to measure variations in the local temperature and voltage of proton exchange membrane fuel cells (PEMFC that are based on micro-electro-mechanical systems (MEMS. The power density at 0.5 V without a sensor is 450 mW/cm2, and that with a sensor is 426 mW/cm2. Since the reaction area of a fuel cell with a sensor is approximately 12% smaller than that without a sensor, but the performance of the former is only 5% worse.

  16. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

    2016-10-05

    The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

  17. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  18. About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

    Science.gov (United States)

    Miara, Lincoln; Windmüller, Anna; Tsai, Chih-Long; Richards, William D; Ma, Qianli; Uhlenbruck, Sven; Guillon, Olivier; Ceder, Gerbrand

    2016-10-12

    The reactivity of mixtures of high voltage spinel cathode materials Li 2 NiMn 3 O 8 , Li 2 FeMn 3 O 8 , and LiCoMnO 4 cosintered with Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 and Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable Li 2 MnO 3 and then decompose to form stable and often insulating phases such as La 2 Zr 2 O 7 , La 2 O 3 , La 3 TaO 7 , TiO 2 , and LaMnO 3 which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 mixtures, the Mn tends to oxidize to MnO 2 or Mn 2 O 3 , supplying lithium to the electrolyte for the formation of Li 3 PO 4 and metal phosphates such as AlPO 4 and LiMPO 4 (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.

  19. Low cost photomultiplier high-voltage readout system

    International Nuclear Information System (INIS)

    Oxoby, G.J.; Kunz, P.F.

    1976-10-01

    The Large Aperture Solenoid Spectrometer (LASS) at Stanford Linear Accelerator Center (SLAC) requires monitoring over 300 voltages. This data is recorded on magnetic tapes along with the event data. It must also be displayed so that operators can easily monitor and adjust the voltages. A low-cost high-voltage readout system has been implemented to offer stand-alone digital readout capability as well as fast data transfer to a host computer. The system is flexible enough to permit use of a DVM or ADC and commercially available analogue multiplexers

  20. Design & Fabrication of a High-Voltage Photovoltaic Cell

    Energy Technology Data Exchange (ETDEWEB)

    Felder, Jennifer; /North Carolina State U. /SLAC

    2012-09-05

    Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.

  1. High Voltage Power Transmission for Wind Energy

    Science.gov (United States)

    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.

  2. Micro controller application as x-ray machine's high voltage controller

    International Nuclear Information System (INIS)

    Wiranto Budi Santoso; Beny Syawaludin

    2010-01-01

    The micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive the stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-B051 compiler. The test results show that the stepper motor could rotate according to an input value. (author)

  3. Integrated differential high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Farch, Kjartan

    2015-01-01

    In this paper an integrated differential high-voltage transmitting circuit for capacitive micromachined ultrasonic transducers (CMUTs) used in portable ultrasound scanners is designed and implemented in a 0.35 μm high-voltage process. Measurements are performed on the integrated circuit in order...... to assess its performance. The circuit generates pulses at differential voltage levels of 60V, 80V and 100 V, a frequency up to 5MHz and a measured driving strength of 1.75 V/ns with the CMUT connected. The total on-chip area occupied by the transmitting circuit is 0.18 mm2 and the power consumption...

  4. High-voltage pulse generator synchronous with LINAC

    International Nuclear Information System (INIS)

    Muto, M.; Hiratsuka, Yoshio; Niimura, Nobuo

    1974-01-01

    High-voltage pulse generator (H.V. Flip-Flop) No.2, an improved type of No.1, is described, which is used in the structural analysis of transient phenomena in materials through the neutron TOF with a Linac. The method of producing positive and negative high-voltage pulses synchronous with the Linac is identical with that in No.1. However, No.2 has outstanding features as follows: (1) The rise time of output pulses is reduced to 0.3 msec, due to the improvement of switching circuit and the winding of a step-up transformer; (2) The widths of positive and negative pulses are variable up to maximum 8 and 16 frames, respectively (One frame = 10 msec); (3) The distribution of TOF signals from a BF 3 counter to a time analyzer is possible even in the negative voltage duration. The panel is provided with the switches for choosing pulse width and the frame for analysis, as well as the dials for setting positive/negative pulse voltage values and the respective indicating meters. (Mori, K)

  5. Experimental Study of Arcing on High-voltage Solar Arrays

    Science.gov (United States)

    Vayner, Boris; Galofaro, Joel; Ferguson, Dale

    2005-01-01

    The main obstacle to the implementation of a high-voltage solar array in space is arcing on the conductor-dielectric junctions exposed to the surrounding plasma. One obvious solution to this problem would be the installation of fully encapsulated solar arrays which were not having exposed conductors at all. However, there are many technological difficulties that must be overcome before the employment of fully encapsulated arrays will turn into reality. An alternative solution to raise arc threshold by modifications of conventionally designed solar arrays looks more appealing, at least in the nearest future. A comprehensive study of arc inception mechanism [1-4] suggests that such modifications can be done in the following directions: i) to insulate conductor-dielectric junction from a plasma environment (wrapthrough interconnects); ii) to change a coverglass geometry (overhang); iii) to increase a coverglass thickness; iiii) to outgas areas of conductor-dielectric junctions. The operation of high-voltage array in LEO produces also the parasitic current power drain on the electrical system. Moreover, the current collected from space plasma by solar arrays determines the spacecraft floating potential that is very important for the design of spacecraft and its scientific apparatus. In order to verify the validity of suggested modifications and to measure current collection five different solar array samples have been tested in large vacuum chamber. Each sample (36 silicon based cells) consists of three strings containing 12 cells connected in series. Thus, arc rate and current collection can be measured on every string independently, or on a whole sample when strings are connected in parallel. The heater installed in the chamber provides the possibility to test samples under temperature as high as 80 C that simulates the LEO operational temperature. The experimental setup is described below.

  6. 30 CFR 18.54 - High-voltage continuous mining machines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage continuous mining machines. 18.54... and Design Requirements § 18.54 High-voltage continuous mining machines. (a) Separation of high... ground. (e) Onboard ungrounded, three-phase power circuit. A continuous mining machine designed with an...

  7. Current, voltage and temperature distribution modeling of light-emitting diodes based on electrical and thermal circuit analysis

    International Nuclear Information System (INIS)

    Yun, J; Shim, J-I; Shin, D-S

    2013-01-01

    We demonstrate a modeling method based on the three-dimensional electrical and thermal circuit analysis to extract current, voltage and temperature distributions of light-emitting diodes (LEDs). In our model, the electrical circuit analysis is performed first to extract the current and voltage distributions in the LED. Utilizing the result obtained from the electrical circuit analysis as distributed heat sources, the thermal circuit is set up by using the duality between Fourier's law and Ohm's law. From the analysis of the thermal circuit, the temperature distribution at each epitaxial film is successfully obtained. Comparisons of experimental and simulation results are made by employing an InGaN/GaN multiple-quantum-well blue LED. Validity of the electrical circuit analysis is confirmed by comparing the light distribution at the surface. Since the temperature distribution at each epitaxial film cannot be obtained experimentally, the apparent temperature distribution is compared at the surface of the LED chip. Also, experimentally obtained average junction temperature is compared with the value calculated from the modeling, yielding a very good agreement. The analysis method based on the circuit modeling has an advantage of taking distributed heat sources as inputs, which is essential for high-power devices with significant self-heating. (paper)

  8. Damage structure of gallium arsenide irradiated in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Loretto, D.; Loretto, M.H.

    1989-01-01

    Semi-insulating undoped gallium arsenide has been irradiated in a high-voltage electron microscope between room temperature and about 500 0 C for doses of up to 5 x 10 22 electrons cm -2 at 1 MeV. Room-temperature irradiation produces small (less than 5 nm) damage clusters. As the temperature of the irradiation is increased, the size of these clusters increases, until at about 300 0 C a high density of dislocation loops can be resolved. The dislocation loops, 20 nm or less in diameter, which are produced at about 500 0 C have been analysed in a bright field using a two-beam inside-outside method which minimises the tilt necessary between micrographs. It is concluded that the loops are an interstitial perfect-edge type with a Burgers vector of (a/2) . (author)

  9. Development of a high throughput single-particle screening for inorganic semiconductor nanorods as neural voltage sensor

    Science.gov (United States)

    Kuo, Yung; Park, Kyoungwon; Li, Jack; Ingargiola, Antonino; Park, Joonhyuck; Shvadchak, Volodymyr; Weiss, Shimon

    2017-08-01

    Monitoring membrane potential in neurons requires sensors with minimal invasiveness, high spatial and temporal (sub-ms) resolution, and large sensitivity for enabling detection of sub-threshold activities. While organic dyes and fluorescent proteins have been developed to possess voltage-sensing properties, photobleaching, cytotoxicity, low sensitivity, and low spatial resolution have obstructed further studies. Semiconductor nanoparticles (NPs), as prospective voltage sensors, have shown excellent sensitivity based on Quantum confined Stark effect (QCSE) at room temperature and at single particle level. Both theory and experiment have shown their voltage sensitivity can be increased significantly via material, bandgap, and structural engineering. Based on theoretical calculations, we synthesized one of the optimal candidates for voltage sensors: 12 nm type-II ZnSe/CdS nanorods (NRs), with an asymmetrically located seed. The voltage sensitivity and spectral shift were characterized in vitro using spectrally-resolved microscopy using electrodes grown by thin film deposition, which "sandwich" the NRs. We characterized multiple batches of such NRs and iteratively modified the synthesis to achieve higher voltage sensitivity (ΔF/F> 10%), larger spectral shift (>5 nm), better homogeneity, and better colloidal stability. Using a high throughput screening method, we were able to compare the voltage sensitivity of our NRs with commercial spherical quantum dots (QDs) with single particle statistics. Our method of high throughput screening with spectrally-resolved microscope also provides a versatile tool for studying single particles spectroscopy under field modulation.

  10. The analysis of energy efficiency in water electrolysis under high temperature and high pressure

    Science.gov (United States)

    Hourng, L. W.; Tsai, T. T.; Lin, M. Y.

    2017-11-01

    This paper aims to analyze the energy efficiency of water electrolysis under high pressure and high temperature conditions. The effects of temperature and pressure on four different kinds of reaction mechanisms, namely, reversible voltage, activation polarization, ohmic polarization, and concentration polarization, are investigated in details. Results show that the ohmic and concentration over-potentials are increased as temperature is increased, however, the reversible and activation over-potentials are decreased as temperature is increased. Therefore, the net efficiency is enhanced as temperature is increased. The efficiency of water electrolysis at 350°C/100 bars is increased about 17%, compared with that at 80°C/1bar.

  11. Tests of industrial ethylene-propylene rubber high voltage cable for cryogenic use

    CERN Document Server

    Balhan, B; Goddard, B; Muratori, G; Otwinowski, S; Rieubland, Jean Michel; Wang, H; CERN. Geneva. SPS and LEP Division

    1999-01-01

    At the beginning of 1999 UCLA has received a prototype High Voltage Cryogenic Cable supplied fee of charge by Pirelli. The cable is intended for more than ten years of service at 100 kV D.C. and liquid argon temperature. Thecable uses an all welded construction, whichi is axially tight and free of ionizable voids. The cable was submitted to a number of mechanical and electrical tests as described below.

  12. High-Voltage, Low-Power BNC Feedthrough Terminator

    Science.gov (United States)

    Bearden, Douglas

    2012-01-01

    This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

  13. High-Capacity Cathode Material with High Voltage for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Xiao, Dong-Dong; Ge, Mingyuan; Yu, Xiqian; Chu, Yong; Huang, Xiaojing; Zhang, Xu-Dong; Yin, Ya-Xia; Yang, Xiao-Qing; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2018-03-01

    Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg -1 . The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Organic dielectrics in high voltage cables

    Energy Technology Data Exchange (ETDEWEB)

    Vermeer, J

    1962-03-01

    It appears that the limit has been reached in the applicability of oil-impregnated paper as the dielectric for ehv cables, as with rising voltages the prevention of conductor losses becomes increasingly difficult, while the dielectric losses of the insulation, increasing as the square of the voltage, contribute to a greater extent to the temperature rise of the conductor. The power transmitting capacity of ehv cables reaches a maximum at 500 to 600 kV for these reasons. Apart from artificial cooling, a substantial improvement can be obtained only with the use of insulating materials with much lower dielectric losses; these can moreover be applied with a smaller wall thickness, but this means higher field strengths. Synthetic polymer materials meet these requirements but can be used successfully only in the form of lapped film tapes impregnated with suitable liquids. The electrical properties of these heterogeneous dielectrics, in particular, their impulse breakdown strengths are studied in detail.

  15. Operational Modelling of High Temperature Electrolysis (HTE)

    International Nuclear Information System (INIS)

    Patrick Lovera; Franck Blein; Julien Vulliet

    2006-01-01

    Solid Oxide Fuel Cells (SOFC) and High Temperature Electrolysis (HTE) work on two opposite processes. The basic equations (Nernst equation, corrected by a term of over-voltage) are thus very similar, only a few signs are different. An operational model, based on measurable quantities, was finalized for HTE process, and adapted to SOFCs. The model is analytical, which requires some complementary assumptions (proportionality of over-tensions to the current density, linearization of the logarithmic term in Nernst equation). It allows determining hydrogen production by HTE using a limited number of parameters. At a given temperature, only one macroscopic parameter, related to over-voltages, is needed for adjusting the model to the experimental results (SOFC), in a wide range of hydrogen flow-rates. For a given cell, this parameter follows an Arrhenius law with a satisfactory precision. The prevision in HTE process is compared to the available experimental results. (authors)

  16. First high-voltage measurements using Ca{sup +} ions at the ALIVE experiment

    Energy Technology Data Exchange (ETDEWEB)

    König, K., E-mail: kkoenig@ikp.tu-darmstadt.de [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Geppert, Ch. [Universität Mainz, Institut für Kernchemie (Germany); Krämer, J.; Maaß, B. [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Otten, E. W. [Universität Mainz, Institut für Physik (Germany); Ratajczyk, T.; Nörtershäuser, W. [Technische Universität Darmstadt, Institut für Kernphysik (Germany)

    2017-11-15

    Many physics experiments depend on accurate high-voltage measurements to determine for example the exact retardation potential of an electron spectrometer as in the KATRIN experiment or the acceleration voltage of the ions at ISOL facilities. Until now only precision high-voltage dividers can be used to measure voltages up to 65 kV with an accuracy of 1 ppm. However, these dividers need frequent calibration and cross-checking and the direct traceability is not given. In this article we will describe the status of an experiment which aims to measure high voltages using collinear laser spectroscopy and which has the potential to provide a high-voltage standard and hence, a calibration source for precision high-voltage dividers on the 1 ppm level.

  17. High voltage switches having one or more floating conductor layers

    Science.gov (United States)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  18. Room temperature direct bonding of LiNbO3 crystal layers and its application to high-voltage optical sensing

    International Nuclear Information System (INIS)

    Tulli, D; Janner, D; Pruneri, V

    2011-01-01

    LiNbO 3 is a crystal widely used in photonics and acoustics, for example in electro-optic modulation, nonlinear optical frequency conversion, electric field sensing and surface acoustic wave filtering. It often needs to be combined with other materials and used in thin layers to achieve the adequate device performance. In this paper, we investigate direct bonding of LiNbO 3 crystals with other dielectric materials, such as Si and fused silica (SiO 2 ), and we show that specific surface chemical cleaning, together with Ar or O 2 plasma activation, can be used to increase the surface free energy and achieve effective bonding at room temperature. The resulting hybrid material bonding is very strong, making the dicing and grinding of LiNbO 3 layers as thin as 15 µm possible. To demonstrate the application potentials of the proposed bonding technique, we have fabricated and characterized a high-voltage field sensor with high sensitivity in a domain inverted and bonded LiNbO 3 waveguide substrate

  19. Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit

    Science.gov (United States)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Mathers, Alex

    2012-01-01

    NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

  20. A compact, all solid-state LC high voltage generator.

    Science.gov (United States)

    Fan, Xuliang; Liu, Jinliang

    2013-06-01

    LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

  1. Performance of High Temperature Operational Amplifier, Type LM2904WH, under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Operation of electronic parts and circuits under extreme temperatures is anticipated in NASA space exploration missions as well as terrestrial applications. Exposure of electronics to extreme temperatures and wide-range thermal swings greatly affects their performance via induced changes in the semiconductor material properties, packaging and interconnects, or due to incompatibility issues between interfaces that result from thermal expansion/contraction mismatch. Electronics that are designed to withstand operation and perform efficiently in extreme temperatures would mitigate risks for failure due to thermal stresses and, therefore, improve system reliability. In addition, they contribute to reducing system size and weight, simplifying its design, and reducing development cost through the elimination of otherwise required thermal control elements for proper ambient operation. A large DC voltage gain (100 dB) operational amplifier with a maximum junction temperature of 150 C was recently introduced by STMicroelectronics [1]. This LM2904WH chip comes in a plastic package and is designed specifically for automotive and industrial control systems. It operates from a single power supply over a wide range of voltages, and it consists of two independent, high gain, internally frequency compensated operational amplifiers. Table I shows some of the device manufacturer s specifications.

  2. Recycling potential for low voltage and high voltage high rupturing capacity fuse links.

    Science.gov (United States)

    Psomopoulos, Constantinos S; Barkas, Dimitrios A; Kaminaris, Stavros D; Ioannidis, George C; Karagiannopoulos, Panagiotis

    2017-12-01

    Low voltage and high voltage high-rupturing-capacity fuse links are used in LV and HV installations respectively, protecting mainly the LV and HV electricity distribution and transportation networks. The Waste Electrical and Electronic Equipment Directive (2002/96/EC) for "Waste of electrical and electronic equipment" is the main related legislation and as it concerns electrical and electronic equipment, it includes electric fuses. Although, the fuse links consist of recyclable materials, only small scale actions have been implemented for their recycling around Europe. This work presents the possibilities for material recovery from this specialized industrial waste for which there are only limited volume data. Furthermore, in order to present the huge possibilities and environmental benefits, it presents the potential for recycling of HRC fuses used by the Public Power Corporation of Greece, which is the major consumer for the country, but one of the smallest ones in Europe and globally, emphasizing in this way in the issue. According to the obtained results, fuse recycling could contribute to the effort for minimize the impacts on the environment through materials recovery and reduction of the wastes' volume disposed of in landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 30 CFR 18.53 - High-voltage longwall mining systems.

    Science.gov (United States)

    2010-07-01

    ...-starter enclosure, with the exception of a controller on a high-voltage shearer, the disconnect device...) shielding between the primary and secondary windings. The shielding must be connected to equipment ground by... with a disconnect device installed to deenergize all high-voltage power conductors extending from the...

  4. Square-Wave Voltage Injection Algorithm for PMSM Position Sensorless Control With High Robustness to Voltage Errors

    DEFF Research Database (Denmark)

    Ni, Ronggang; Xu, Dianguo; Blaabjerg, Frede

    2017-01-01

    relationship with the magnetic field distortion. Position estimation errors caused by higher order harmonic inductances and voltage harmonics generated by the SVPWM are also discussed. Both simulations and experiments are carried out based on a commercial PMSM to verify the superiority of the proposed method......Rotor position estimated with high-frequency (HF) voltage injection methods can be distorted by voltage errors due to inverter nonlinearities, motor resistance, and rotational voltage drops, etc. This paper proposes an improved HF square-wave voltage injection algorithm, which is robust to voltage...... errors without any compensations meanwhile has less fluctuation in the position estimation error. The average position estimation error is investigated based on the analysis of phase harmonic inductances, and deduced in the form of the phase shift of the second-order harmonic inductances to derive its...

  5. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3) Such...

  6. Planning aspects of ac extra high voltage lines

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, H

    1964-01-01

    The technical points arising in any project for application of higher voltages on power grids in Europe are discussed. The cost aspects of two alternative ways of extending the voltage level of existing systems are discussed in detail. The short-circuit current in a high-power system with isolated or grounded neutral point and its relation to the mode of grounding is examined. For a transmission distance of 200 kVm, operating cost for each kWh transmitted are shown on curves for voltages of 220, 380 and 700 kV against transmitted energy. This shows that for any rated voltage there is a range of energy values which can be transmitted economically. Factors to be considered in maintaining, selecting or rejecting transformers and switchgear of other systems for higher voltage purposes are mentioned.

  7. Insulation co-ordination in high-voltage electric power systems

    CERN Document Server

    Diesendorf, W

    2015-01-01

    Insulation Co-ordination in High-Voltage Electric Power Systems deals with the methods of insulation needed in different circumstances. The book covers topics such as overvoltages and lightning surges; disruptive discharge and withstand voltages; self-restoring and non-self-restoring insulation; lightning overvoltages on transmission lines; and the attenuation and distortion of lightning surges. Also covered in the book are topics such as the switching surge designs of transmission lines, as well as the insulation coordination of high-voltage stations. The text is recommended for electrical en

  8. Analysis of transistor and snubber turn-off dynamics in high-frequency high-voltage high-power converters

    Science.gov (United States)

    Wilson, P. M.; Wilson, T. G.; Owen, H. A., Jr.

    Dc to dc converters which operate reliably and efficiently at switching frequencies high enough to effect substantial reductions in the size and weight of converter energy storage elements are studied. A two winding current or voltage stepup (buck boost) dc-to-dc converter power stage submodule designed to operate in the 2.5-kW range, with an input voltage range of 110 to 180 V dc, and an output voltage of 250 V dc is emphasized. In order to assess the limitations of present day component and circuit technologies, a design goal switching frequency of 10 kHz was maintained. The converter design requirements represent a unique combination of high frequency, high voltage, and high power operation. The turn off dynamics of the primary circuit power switching transistor and its associated turn off snubber circuitry are investigated.

  9. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    Science.gov (United States)

    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.

  10. A low knee voltage and high breakdown voltage of 4H-SiC TSBS employing poly-Si/Ni Schottky scheme

    Science.gov (United States)

    Kim, Dong Young; Seok, Ogyun; Park, Himchan; Bahng, Wook; Kim, Hyoung Woo; Park, Ki Cheol

    2018-02-01

    We report a low knee voltage and high breakdown voltage 4H-SiC TSBS employing poly-Si/Ni dual Schottky contacts. A knee voltage was significantly improved from 0.75 to 0.48 V by utilizing an alternative low work-function material of poly-Si as an anode electrode. Also, reverse breakdown voltage was successfully improved from 901 to 1154 V due to a shrunk low-work-function Schottky region by a proposed self-align etching process between poly-Si and SiC. SiC TSBS with poly-Si/Ni dual Schottky scheme is a suitable structure for high-efficiency rectification and high-voltage blocking operation.

  11. Application of high voltage electric field (HVEF) drying technology in potato chips

    International Nuclear Information System (INIS)

    Bai, Yaxiang; Shi, Hua; Yang, Yaxin

    2013-01-01

    In order to improve the drying efficiency and qualities of vegetable by high voltage electric field (HVEF), potato chips as a representative of vegetable was dried using a high voltage electric drying systems at 20°C. The shrinkage rate, water absorption and rehydration ratio of dried potato chips were measured. The results indicated that the drying rate of potato chips was significantly improved in the high voltage electric drying systems. The shrinkage rate of potato chips dried by high voltage electric field was 1.1% lower than that by oven drying method. And the rehydration rate of high voltage electric field was 24.6% higher than that by oven drying method. High voltage electric field drying is very advantageous and can be used as a substitute for traditional drying method.

  12. X-ray spectral meter of high voltages for X-ray apparatuses

    International Nuclear Information System (INIS)

    Zubkov, I.P.; Larchikov, Yu.V.

    1993-01-01

    Design of the X-ray spectral meter of high voltages (XRSMHV) for medical X-ray apparatuses permitting to conduct the voltage measurements without connection to current circuits. The XRSMHV consists of two main units: the detector unit based on semiconductor detector and the LP4900B multichannel analyzer (Afora, Finland). The XRSMYV was tested using the pilot plant based on RUM-20 X-ray diagnostic apparatus with high-voltage regulator. It was shown that the developed XRSMHV could be certify in the range of high constant voltages form 40 up to 120 kV with the basic relative error limits ±0.15%. The XRSMHV is used at present as the reference means for calibration of high-voltage medical X-ray equipment

  13. An implantable neurostimulator with an integrated high-voltage inductive power-recovery frontend

    International Nuclear Information System (INIS)

    Wang Yuan; Zhang Xu; Liu Ming; Li Peng; Chen Hongda

    2014-01-01

    This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery frontend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full-wave rectifier (up to 100 V AC input), high-voltage series regulators (24/5 V outputs) and a linear regulator (1.8/3.3 V output) with bandgap voltage reference. With the high voltage output of the series regulator, the proposed neurostimulator could deliver a considerably large current in high electrode-tissue contact impedance. This neurostimulator has been fabricated in a CSMC 1 μm 5/40/700 V BCD process and the total silicon area including pads is 5.8 mm 2 . Preliminary tests are successful as the neurostimulator shows good stability under a 13.56 MHz AC supply. Compared to previously reported works, our design has advantages of a wide induced voltage range (26–100 V), high output voltage (up to 24 V) and high-level integration, which are suitable for implantable neurostimulators. (semiconductor integrated circuits)

  14. High-voltage transistor converter for pulsed x-ray sources

    International Nuclear Information System (INIS)

    Krasil'nikov, S.B.; Kristalinskii, A.L.; Lozovoi, L.N.; Markov, S.N.; Sindalovskii, E.I.

    1986-01-01

    A 24-V/12-kV converter for MIRA-2D and NORA pulsed x-ray sources is described. When the low-voltage supply varies within 20-26 V, the frequency stability of the x-ray pulses is higher by a factor of 3 ≅ 3 than when the PRIMA converter is used. For 14-24 V, the average output power of the converter is independent of the load impedance and increases linearly with an increase in supply voltage. The efficiency of the converter reaches 60%. The converter operates in the temperature range of -40 to +60 0 C

  15. Precision High-Voltage DC Dividers and Their Calibration

    Czech Academy of Sciences Publication Activity Database

    Dragounová, Naděžda

    2005-01-01

    Roč. 54, č. 5 (2005), s. 1911-1915 ISSN 0018-9456 R&D Projects: GA AV ČR KSK1048102; GA ČR GA202/03/0889 Keywords : calibration * dc voltage * high voltage (HV) Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.665, year: 2005

  16. Contact spectroscopy of high-temperature superconductors. Review

    International Nuclear Information System (INIS)

    Yanson, I.K.

    1991-01-01

    We have attempted to systematize the research of high temperature superconductors by means of tunneling and point-contact spectroscopy. The theoretical grounds of the methods are briefly described. The deviations of current-voltage characteristics from ordinary superconductors are considered. The properties of point contacts with direct energy gap measurfements and the fine structure of derivatives of i(v) curves at the overlap energies are reviewed for the high-T c La 2-x Sr x CuO 4 materials

  17. Process engineering of high voltage alginate encapsulation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Gryshkov, Oleksandr; Pogozhykh, Denys; Zernetsch, Holger; Hofmann, Nicola; Mueller, Thomas; Glasmacher, Birgit

    2014-01-01

    Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200–400 μm) with narrow size distribution (± 5–7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15–25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate–cell interaction within these structures will be forthcoming. - Highlights: • High voltage alginate encapsulation of mesenchymal stem cells (MSCs) was designed. • Reproducible and spherical alginate beads were generated via high voltage. • Air flow encapsulation was utilized as a comparative approach to high voltage. • High voltage did not alter the viability and proliferation of encapsulated MSCs. • High voltage encapsulation can be scaled up and applied in cell-based therapy

  18. High voltage power network construction

    CERN Document Server

    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.

  19. High Bandwidth Zero Voltage Injection Method for Sensorless Control of PMSM

    DEFF Research Database (Denmark)

    Ge, Xie; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2014-01-01

    High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses to be inj......High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses...... in a fast current regulation performance. Injection of zero voltage also minimizes the inverter voltage error effects caused by the dead-time....

  20. Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Jaekyun Kim

    2015-10-01

    Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

  1. Room temperature resistive state switching with hysteresis in GdMnO3 thin film with low threshold voltage

    International Nuclear Information System (INIS)

    Nath, Rajib; Raychaudhuri, A. K.; Mukovskii, Ya. M.; Andreev, N.; Chichkov, Vladimir

    2014-01-01

    In this paper, we report a room temperature resistive state switching with hysteresis, in a thin film of GdMnO 3 grown on NdGaO 3 substrate. The switched states have a resistance ratio ≈10 3 . The switching is unipolar in nature, with a low set voltage <3 V, while the reset voltage <0.3 V. The switching occurs between a high resistance polaronic insulating state and a low resistance metallic state. The resistance state transition has been ascribed to an electronic mechanism that originates from co-existing phases (created by charge disproportionation) that can undergo a percolative transition enabled by the applied bias

  2. Digitally Programmable High-Q Voltage Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    D. Singh

    2013-12-01

    Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

  3. High temperature spectral emissivity measurement using integral blackbody method

    Science.gov (United States)

    Pan, Yijie; Dong, Wei; Lin, Hong; Yuan, Zundong; Bloembergen, Pieter

    2016-10-01

    Spectral emissivity is a critical material's thermos-physical property for heat design and radiation thermometry. A prototype instrument based upon an integral blackbody method was developed to measure material's spectral emissivity above 1000 °. The system was implemented with an optimized commercial variable-high-temperature blackbody, a high speed linear actuator, a linear pyrometer, and an in-house designed synchronization circuit. A sample was placed in a crucible at the bottom of the blackbody furnace, by which the sample and the tube formed a simulated blackbody which had an effective total emissivity greater than 0.985. During the measurement, the sample was pushed to the end opening of the tube by a graphite rod which was actuated through a pneumatic cylinder. A linear pyrometer was used to monitor the brightness temperature of the sample surface through the measurement. The corresponding opto-converted voltage signal was fed and recorded by a digital multi-meter. A physical model was proposed to numerically evaluate the temperature drop along the process. Tube was discretized as several isothermal cylindrical rings, and the temperature profile of the tube was measurement. View factors between sample and rings were calculated and updated along the whole pushing process. The actual surface temperature of the sample at the end opening was obtained. Taking advantages of the above measured voltage profile and the calculated true temperature, spectral emissivity under this temperature point was calculated.

  4. Conceptual design of pulsed high voltage and high precision power supply for a cyclotron auto-resonance maser (CARM) for plasma heating

    International Nuclear Information System (INIS)

    Zito, Pietro; Maffia, Giuseppe; Lampasi, Alessandro

    2015-01-01

    Highlights: • ENEA started a project to develop a cyclotron auto-resonance maser (CARM). • This facility requires an advanced pulsed high voltage power supply (HVPS). • The conceptual design answers to the performances requested for CARM HVPS. • The pulse transformer parameters were estimated according to IEEE standards. • PWM PID-based controller has been optimized to follow very fast rectangular pulses. - Abstract: Due to the high electron temperature during the plasma burning, both a higher power (>1 MW) and a higher frequency (up to 300 GHz) are required for plasma heating in future fusion experiments like DEMO. For this task, ENEA started a project to develop a cyclotron auto-resonance maser (CARM) able to produce an electron radiation in synchronism with the electromagnetic field and to transfer the electron beam kinetic energy to the plasma. This facility requires an advanced pulsed high voltage power supply (HVPS) with the following technical characteristics: variable output voltage up to 700 kV; variable pulse length in the range 5–50 μs; overshoot < 2%; rise time < 1 μs; voltage accuracy (including drop, ripple and stability) <0.1%. This paper describes the conceptual design and the technical solutions adopted to achieve the performance requested for the CARM HVPS.

  5. Conceptual design of pulsed high voltage and high precision power supply for a cyclotron auto-resonance maser (CARM) for plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Zito, Pietro, E-mail: pietro.zito@enea.it; Maffia, Giuseppe; Lampasi, Alessandro

    2015-10-15

    Highlights: • ENEA started a project to develop a cyclotron auto-resonance maser (CARM). • This facility requires an advanced pulsed high voltage power supply (HVPS). • The conceptual design answers to the performances requested for CARM HVPS. • The pulse transformer parameters were estimated according to IEEE standards. • PWM PID-based controller has been optimized to follow very fast rectangular pulses. - Abstract: Due to the high electron temperature during the plasma burning, both a higher power (>1 MW) and a higher frequency (up to 300 GHz) are required for plasma heating in future fusion experiments like DEMO. For this task, ENEA started a project to develop a cyclotron auto-resonance maser (CARM) able to produce an electron radiation in synchronism with the electromagnetic field and to transfer the electron beam kinetic energy to the plasma. This facility requires an advanced pulsed high voltage power supply (HVPS) with the following technical characteristics: variable output voltage up to 700 kV; variable pulse length in the range 5–50 μs; overshoot < 2%; rise time < 1 μs; voltage accuracy (including drop, ripple and stability) <0.1%. This paper describes the conceptual design and the technical solutions adopted to achieve the performance requested for the CARM HVPS.

  6. 30 CFR 75.802 - Protection of high-voltage circuits extending underground.

    Science.gov (United States)

    2010-07-01

    ...-Voltage Distribution § 75.802 Protection of high-voltage circuits extending underground. (a) Except as... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of high-voltage circuits extending... which shall be grounded through a suitable resistor at the source transformers, and a grounding circuit...

  7. Copper wire theft and high voltage electrical burns

    OpenAIRE

    Francis, Eamon C; Shelley, Odhran P

    2014-01-01

    High voltage electrical burns are uncommon. However in the midst of our economic recession we are noticing an increasing number of these injuries. Copper wire is a valuable commodity with physical properties as an excellent conductor of electricity making it both ubiquitous in society and prized on the black market. We present two consecutive cases referred to the National Burns Unit who sustained life threatening injuries from the alleged theft of high voltage copper wire and its omnipresenc...

  8. A Novel High-Sensitivity, Low-Power, Liquid Crystal Temperature Sensor

    Directory of Open Access Journals (Sweden)

    José Francisco Algorri

    2014-04-01

    Full Text Available A novel temperature sensor based on nematic liquid crystal permittivity as a sensing magnitude, is presented. This sensor consists of a specific micrometric structure that gives considerable advantages from other previous related liquid crystal (LC sensors. The analytical study reveals that permittivity change with temperature is introduced in a hyperbolic cosine function, increasing the sensitivity term considerably. The experimental data has been obtained for ranges from −6 °C to 100 °C. Despite this, following the LC datasheet, theoretical ranges from −40 °C to 109 °C could be achieved. These results have revealed maximum sensitivities of 33 mVrms/°C for certain temperature ranges; three times more than of most silicon temperature sensors. As it was predicted by the analytical study, the micrometric size of the proposed structure produces a high output voltage. Moreover the voltage’s sensitivity to temperature response can be controlled by the applied voltage. This response allows temperature measurements to be carried out without any amplification or conditioning circuitry, with very low power consumption.

  9. Effect of applied DC voltages and temperatures on space charge behaviour of multi-layer oil-paper insulation

    Energy Technology Data Exchange (ETDEWEB)

    Tang Chao; Liao Ruijin [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University (China); Chen, G [School of Electronics and Computer Science, University of Southampton (United Kingdom); Fu, M, E-mail: tangchao_1981@163.co [AVERA T and D Technology Centre, Stafford (United Kingdom)

    2009-08-01

    In this paper, space charge in a multi-layer oil-paper insulation system was investigated using the pulsed electroacoustic (PEA) technique. A series of measurements had been carried following subjection of the insulation system to different applied voltages and different temperatures. Charge behaviours in the insulation system were analyzed and the influence of temperature on charge dynamics was discussed. The test results shows that homocharge injection takes place under all the test conditions, the applied DC voltage mainly affects the amount of space charge, while the temperature has greater influence on the distribution and mobility of space charge inside oil-paper samples.

  10. Compact high voltage, high peak power, high frequency transformer for converter type modulator applications.

    Science.gov (United States)

    Reghu, T; Mandloi, V; Shrivastava, Purushottam

    2016-04-01

    The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

  11. An Integrated Chip High-Voltage Power Receiver for Wireless Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Vijith Vijayakumaran Nair

    2015-06-01

    Full Text Available In near-field wireless-powered biomedical implants, the receiver voltage largely overrides the compliance of low-voltage power receiver systems. To limit the induced voltage, generally, low-voltage topologies utilize limiter circuits, voltage clippers or shunt regulators, which are power-inefficient methods. In order to overcome the voltage limitation and improve power efficiency, we propose an integrated chip high-voltage power receiver based on the step down approach. The topology accommodates voltages as high as 30 V and comprises a high-voltage semi-active rectifier, a voltage reference generator and a series regulator. Further, a battery management circuit that enables safe and reliable implant battery charging based on analog control is proposed and realized. The power receiver is fabricated in 0.35-μm high-voltage Bipolar-CMOS-DMOStechnology based on the LOCOS0.35-μm CMOS process. Measurement results indicate 83.5% power conversion efficiency for a rectifier at 2.1 mA load current. The low drop-out regulator based on the current buffer compensation and buffer impedance attenuation scheme operates with low quiescent current, reduces the power consumption and provides good stability. The topology also provides good power supply rejection, which is adequate for the design application. Measurement results indicate regulator output of 4 ± 0.03 V for input from 5 to 30 V and 10 ± 0.05 V output for input from 11 to 30 V with load current 0.01–100 mA. The charger circuit manages the charging of the Li-ion battery through all if the typical stages of the Li-ion battery charging profile.

  12. Development of High Temperature Capacitor Technology and Manufacturing Capability

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-05-15

    The goal of the Development of High Temperature Capacitor Technology and Manufacturing Capability program was to mature a production-ready supply chain for reliable 250°C FPE (fluorinated polyester) film capacitors by 2011. These high-temperature film capacitors enable both the down hole drilling and aerospace industries by enabling a variety of benefits including: - Deeper oil exploration in higher temperature and pressure environments - Enabling power electronic and control equipment to operate in higher temperature environments - Enabling reduced cooling requirements of electronics - Increasing reliability and life of capacitors operating below rated temperature - Enabling capacitors to handle higher electrical losses without overheating. The key challenges to bringing the FPE film capacitors to market have been manufacturing challenges including: - FPE Film is difficult to handle and wind, resulting in poor yields - Voltage breakdown strength decreases when the film is wound into capacitors (~70% decrease) - Encapsulation technologies must be improved to enable higher perature operation - Manufacturing and test cycle time is very long As a direct result of this program most of the manufacturing challenges have been met. The FPE film production metalization and winding yield has increased to over 82% from 70%, and the voltage breakdown strength of the wound capacitors has increased 270% to 189 V/μm. The high temperature packaging concepts are showing significant progress including promising results for lead attachments and hermetic packages at 200°C and non-hermetic packages at 250°C. Manufacturing and test cycle time will decrease as the market for FPE capacitors develops.

  13. Innovation of High Voltage Supply Adjustment Device on Diagnostic X-Ray Machine

    International Nuclear Information System (INIS)

    Sujatno; Wiranto Budi Santoso

    2010-01-01

    Innovation of high voltage supply adjustment device on diagnostic x-ray machine has been carried out. The innovation is conducted by utilizing an electronic circuit as a high voltage adjustment device. Usually a diagnostic x-ray machine utilizes a transformer or an auto-transformer as a high voltage supply adjustment device. A high power diagnostic x-ray machine needs a high power transformer which has big physical dimension. Therefore a box control where the transformer is located has to have big physical dimension. Besides, the price of the transformer is expensive and hardly found in local markets. In this innovation, the transformer is replaced by an electronic circuit. The main component of the electronic circuit is Triac BTA-40. As adjustment device, the triac is controlled by a variable resistor which is coupled by a stepper motor. A step movement of stepper motor varies a value of resistor. The resistor value determines the triac gate voltage. Furthermore the triac will open according to the value of electrical current flowing to the gate. When the gate is open, electrical voltage and current will flow from cathode to anode of the triac. The value of these electrical voltage and current depend on gate open condition. Then this triac output voltage is feed to diagnostic x-ray machine high voltage supply. Therefore the high voltage value of diagnostic x-ray machine is adjusted by the output voltage of the electronic circuit. By using this electronic circuit, the physical dimension of diagnostic x-ray machine box control and the price of the equipment can be reduced. (author)

  14. A Four-Phase High Voltage Conversion Ratio Bidirectional DC-DC Converter for Battery Applications

    Directory of Open Access Journals (Sweden)

    Li-Kun Xue

    2015-06-01

    Full Text Available This study presents a four-phase interleaved high voltage conversion ratio bidirectional DC-DC converter circuit based on coupled inductors and switched capacitors, which can eliminate the defects of conventional high voltage conversion ratio bidirectional DC-DC converters in terms of high-voltage/current stress, less efficiency and low-power limitation. Parallel channels are used to reduce current stress at the low-voltage side and series connected switched capacitors are used to enlarge voltage conversion ratio, reduce voltage stress and achieve auto current sharing. This paper proposes the operation principle, feature analysis and optimization design considerations. On this basis the objectives of high voltage conversion ratio, low voltage/current stress, high power density, high efficiency and high-power applications can be achieved. Some experimental results based on a 500 W prototype converter (24 V to 48 V at low-voltage side, 400 V at high-voltage side are given to verify the theoretical analysis and the effectiveness of the proposed converter.

  15. Advanced High Voltage Power Device Concepts

    CERN Document Server

    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 ...

  16. To minimized power outage by the application of 'RTV' (room temperature vulcanizing) silicon on high voltage porcelain insulators in Pakistan

    International Nuclear Information System (INIS)

    Hafiz Tehzeeb ul Hassan

    2003-01-01

    In Pakistan power network comprises of 500KV, 220KV, 132KV, 66KV and 33KV transmission lines and 11KV power distribution systems. Number of insulators are used in connected units in the shape of strings with transmission line as per insulation requirements with proper design according to the various kinds of pollution stresses. The transmission lines are passing from or near polluted areas and very dusty plains of Punjab and Sindh provinces. Practices are being used in these transmission lines for removal of accumulated contamination of insulators by periodic cleaning twice a year or de-energized transmission lines. Even then discontinuation of supply takes place in the polluted areas in foggy weather. Special technique of using water repellent (Room Temperature Vulcanizing) silicone coating/paint has been introduced on high voltage disc Insulators to minimize the outage in power net work in Pakistan. Especially in high pollution areas near chemical factories and near brick kilns etc comparison study of coated and uncoated disc Insulators have been carried out by ESDD (Equal Salt Deposit Density) measurement in salt fog chamber. (author)

  17. Copper wire theft and high voltage electrical burns.

    Science.gov (United States)

    Francis, Eamon C; Shelley, Odhran P

    2014-01-01

    High voltage electrical burns are uncommon. However in the midst of our economic recession we are noticing an increasing number of these injuries. Copper wire is a valuable commodity with physical properties as an excellent conductor of electricity making it both ubiquitous in society and prized on the black market. We present two consecutive cases referred to the National Burns Unit who sustained life threatening injuries from the alleged theft of high voltage copper wire and its omnipresence on an international scale.

  18. MOSFET-based high voltage short pulse generator for ultrasonic transducer excitation

    Science.gov (United States)

    Hidayat, Darmawan; Setianto, Syafei, Nendi Suhendi; Wibawa, Bambang Mukti

    2018-02-01

    This paper presents the generation of a high-voltage short pulse for the excitation of high frequency ultrasonic transducers. This is highly required in the purpose of various ultrasonic-based evaluations, particularly when high resolution measurement is necessary. A high voltage (+760 V) DC voltage source was pulsated by an ultrafast switching MOSFET which was driven by a pulse generator circuit consisting of an astable multivibrator, a one-shot multivibrator with Schmitt trigger input and a high current MOSFET driver. The generated pulses excited a 200-kHz and a 1-MHz ultrasonic transducers and tested in the transmission mode propagation to evaluate the performances of the generated pulse. The test results showed the generator were able to produce negative spike pulses up to -760 V voltage with the shortest time-width of 107.1 nanosecond. The transmission-received ultrasonic waves show frequency oscillation at 200 and 961 kHz and their amplitudes varied with the voltage of excitation pulse. These results conclude that the developed pulse generator is applicable to excite transducer for the generation of high frequency ultrasonic waves.

  19. Use of a High-Temperature Superconducting Coil for Magnetic Energy Storage

    International Nuclear Information System (INIS)

    Fagnard, J-F; Crate, D; Jamoye, J-F; Laurent, Ph; Mattivi, B; Cloots, R; Ausloos, M; Genon, A; Vanderbemden, Ph

    2006-01-01

    A high temperature superconducting magnetic energy storage device (SMES) has been realised using a 350 m-long BSCCO tape wound as a ''pancake'' coil. The coil is mounted on a cryocooler allowing temperatures down to 17.2 K to be achieved. The temperature dependence of coil electrical resistance R(T) shows a superconducting transition at T = 102.5 K. Measurements of the V(I) characteristics were performed at several temperatures between 17.2 K and 101.5 K to obtain the temperature dependence of the critical current (using a 1 μV/cm criterion). Critical currents were found to exceed 100 A for T < 30 K. An electronic DC-DC converter was built in order to control the energy flow in and out of the superconducting coil. The converter consists of a MOS transistor bridge switching at a 80 kHz frequency and controlled with standard Pulse Width Modulation (PWM) techniques. The system was tested using a 30 V squared wave power supply as bridge input voltage. The coil current, the bridge input and output voltages were recorded simultaneously. Using a 10 A setpoint current in the superconducting coil, the whole system (coil + DC-DC converter) can provide a stable output voltage showing uninterruptible power supply (UPS) capabilities over 1 s

  20. The influence of electric discharge on the properties of high-temperature superconductors

    International Nuclear Information System (INIS)

    Parashchuk, V.V.

    1990-01-01

    The influence is studied of pulse voltage with amplitude 100 kV and duration 100 to 200 ns on the temperature dependence of diamagnetic susceptibility of yttrium ceramics. As a result of the action of spark discharge on the ceramics, the superconducting transition parameters change. As the number of voltage pulses is increased, the diamagnetic susceptibility and the critical temperature determined by it first increase rapidly, then drop slowly. At the same time the transition in the optimum becomes more sharp. In the case of treatment in the air, Tc increases by 15 K and at discharge in liquid nitrogen by 25 K. It is found that the atmospheric air under certain conditions affects the temperature dependence of the diamagnetic susceptibility of HTSC ceramics. Treatment by a high-voltage spark decreases the susceptibility of the ceramics due to atmospheric effects. The highest efficiency of spark treatment is achieved at discharge in liquid nitrogen. (orig.)

  1. A High Voltage Swing 1.9 GHz PA in Standard CMOS

    NARCIS (Netherlands)

    Aartsen, W.A.J.; Annema, Anne J.; Nauta, Bram

    2002-01-01

    A circuit technique for RF power amplifiers that reliably handle voltage peaks well above the nominal supply voltage is presented. To achieve this high-voltage tolerance the circuit implements switched-cascode transistors that yield reliable operation for voltages up to 7V at RF frequencies in a

  2. High voltage series protection of neutral injectors with crossed-field tubes

    International Nuclear Information System (INIS)

    Hofmann, G.A.; Thomas, D.G.

    1976-01-01

    High voltage neutral beam injectors for fusion machines require either parallel or series protection schemes to limit fault currents in case of arcing to safe levels. The protection device is usually located between the high voltage supply and beam injector and either crowbars (parallel protection) or disconnects (series protection) the high voltage supply when a fault occurs. Because of its isolating property, series protection is preferred. The Hughes crossed-field tube is uniquely suited for series protection schemes. The tube can conduct 40 A continuously upon application of voltage (approximately 300 V) and a static magnetic field (approximately 100 G). It is also capable of interrupting currents of 1000 A within 10 μs and withstand voltage of more than 120 kV. Experiments were performed to simulate the duty of a crossed-field tube as a series protection element in a neutral injector circuit under fault conditions. Results of on-switching tests under high and low voltage and interruption of fault currents are presented. An example of a possible protection circuit with crossed-field tubes is discussed

  3. High-voltage pixel sensors for ATLAS upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Perić, I., E-mail: ivan.peric@ziti.uni-heidelberg.de [Heidelberg University, Institute of Computer Engineering, Mannheim (Germany); Kreidl, C.; Fischer, P. [Heidelberg University, Institute of Computer Engineering, Mannheim (Germany); Bompard, F.; Breugnon, P.; Clemens, J.-C.; Fougeron, D.; Liu, J.; Pangaud, P.; Rozanov, A.; Barbero, M. [CPPM, Marseille (France); Feigl, S.; Capeans, M.; Ferrere, D.; Pernegger, H.; Ristic, B. [CERN, Geneve (Switzerland); Muenstermann, D.; Gonzalez Sevilla, S.; La Rosa, A.; Miucci, A. [University of Geneve (Switzerland); and others

    2014-11-21

    The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180 nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.

  4. Evaluation of high temperature capacitor dielectrics

    Science.gov (United States)

    Hammoud, Ahmad N.; Myers, Ira T.

    1992-01-01

    Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

  5. Dimethylacetamide as a film-forming additive for improving the cyclic stability of high voltage lithium-rich cathode at room and elevated temperature

    International Nuclear Information System (INIS)

    Tu, Wenqiang; Xing, Lidan; Xia, Pan; Xu, Mengqing; Liao, Youhao; Li, Weishan

    2016-01-01

    Highlights: • Addition of 1% DMAc improves the cyclic performances of LLO at room and elevated temperature. • DMAc oxidizes previously to the STD electrolyte and generates a protective film on the LLO surface. • The protective film is thin and uniform. - Abstract: In this work, dimethylacetamide (DMAc) was investigated as an electrolyte film-forming additive to improve the cyclic stability of high voltage Lithium-rich layered nickel manganese cobalt oxide (LLO) cathode at room (25 °C) and elevated (55 °C) temperature. At 0.5C rate, addition of 1% DMAc slightly decreases the initial discharge capacity of LLO from 187 to 179 mAh g −1 at room temperature and 255 to 246 mAh g −1 at elevated temperature, while significantly improves the capacity retention of LLO from 65.8% to 80.2% after 200 cycles at room temperature and from 21.1% to 66.7% after 150 cycles at elevated temperature. The mechanism of DMAc improving the cyclic stability of LLO was investigated via theoretical calculation and experimental characterizations, which demonstrated that DMAc oxidized preferential to the STD (1.0 M LiPF 6 in a mixed solvent of ethylene carbonate/ethyl methyl carbonate/diethyl carbonate) electrolyte, generating a thin and uniform film on the LLO surface. This film effectively suppresses the subsequent decomposition of STD electrolyte and further degradation of spinel phase converted from the layered structure of LLO, resulting in improved cyclic stability of LLO at room and elevated temperature.

  6. Room-temperature low-voltage electroluminescence in amorphous carbon nitride thin films

    Science.gov (United States)

    Reyes, R.; Legnani, C.; Ribeiro Pinto, P. M.; Cremona, M.; de Araújo, P. J. G.; Achete, C. A.

    2003-06-01

    White-blue electroluminescent emission with a voltage bias less than 10 V was achieved in rf sputter-deposited amorphous carbon nitride (a-CN) and amorphous silicon carbon nitride (a-SiCN) thin-film-based devices. The heterojunction structures of these devices consist of: Indium tin oxide (ITO), used as a transparent anode; amorphous carbon film as an emission layer, and aluminum as a cathode. The thickness of the carbon films was about 250 Å. In all of the produced diodes, a stable visible emission peaked around 475 nm is observed at room temperature and the emission intensity increases with the current density. For an applied voltage of 14 V, the luminance was about 3 mCd/m2. The electroluminescent properties of the two devices are discussed and compared.

  7. Temperature-dependent DC characteristics of AlInN/GaN high-electron-mobility transistors

    Science.gov (United States)

    Kim, Seongjun; Ahn, Kwang-Soon; Ryou, Jae-Hyun; Kim, Hyunsoo

    2017-07-01

    A 1.5 μm gate AlInN:Mg/GaN HEMT, exhibiting a maximum drain current ( I DS,max) of 700 mA/mm at a gate bias voltage ( V GS) of 0 V and a maximum transconductance ( g m,max) of 190 mS/mm at drain-source voltage ( V DS) of 5 V, was analyzed at temperatures ranging from 210 K to 420 K. It was found that I DS,max and g m,max have weak temperature dependence with a power-law relation of T -0.5, owing to suppressed optical phonon scattering. The threshold voltage ( V th) was found to be stable under increasing temperatures owing to the use of a semi-insulating AlInN:Mg barrier. This indicates that AlInN:Mg/GaN HEMTs are promising candidates for high-temperature electronics applications.[Figure not available: see fulltext.

  8. High-voltage short-fall pulse generator

    International Nuclear Information System (INIS)

    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

  9. High-conductance low-voltage organic thin film transistor with locally rearranged poly(3-hexylthiophene) domain by current annealing on plastic substrate

    Science.gov (United States)

    Pei, Zingway; Tsai, Hsing-Wang; Lai, Hsin-Cheng

    2016-02-01

    The organic material based thin film transistors (TFTs) are attractive for flexible optoelectronics applications due to the ability of lager area fabrication by solution and low temperature process on plastic substrate. Recently, the research of organic TFT focus on low operation voltage and high output current to achieve a low power organic logic circuit for optoelectronic device,such as e-paper or OLED displayer. To obtain low voltage and high output current, high gate capacitance and high channel mobility are key factors. The well-arranged polymer chain by a high temperature postannealing, leading enhancement conductivity of polymer film was a general method. However, the thermal annealing applying heat for all device on the substrate and may not applicable to plastic substrate. Therefore, in this work, the low operation voltage and high output current of polymer TFTs was demonstrated by locally electrical bias annealing. The poly(styrene-comethyl methacrylate) (PS-r-PMMA) with ultra-thin thickness is used as gate dielectric that the thickness is controlled by thermal treatment after spin coated on organic electrode. In electrical bias-annealing process, the PS-r- PMMA is acted a heating layer. After electrical bias-annealing, the polymer TFTs obtain high channel mobility at low voltage that lead high output current by a locally annealing of P3HT film. In the future, the locally electrical biasannealing method could be applied on plastic substrate for flexible optoelectronic application.

  10. Copper wire theft and high voltage electrical burns

    Science.gov (United States)

    Francis, Eamon C; Shelley, Odhran P

    2014-01-01

    High voltage electrical burns are uncommon. However in the midst of our economic recession we are noticing an increasing number of these injuries. Copper wire is a valuable commodity with physical properties as an excellent conductor of electricity making it both ubiquitous in society and prized on the black market. We present two consecutive cases referred to the National Burns Unit who sustained life threatening injuries from the alleged theft of high voltage copper wire and its omnipresence on an international scale. PMID:25356371

  11. Microparticles in high-voltage accelerator tubes

    International Nuclear Information System (INIS)

    Griffith, G.L.; Eastham, D.A.

    1979-01-01

    Microparticles with radii greater than 2 μm have been observed in a high voltage vacuum accelerator tube. The charge acquired by most of the particles is similar to the contact charging of a conducting sphere on a plane. (author)

  12. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  13. An inverted-geometry, high voltage polarized electron gun with UHV load lock

    International Nuclear Information System (INIS)

    Breidenbach, M.; Foss, M.; Hodgson, J.; Kulikov, A.; Odian, A.; Putallaz, G.; Rogers, H.; Schindler, R.; Skarpaas, K.; Zolotorev, M.

    1994-01-01

    The design of a high voltage electron source with a GaAs photocathode and a load lock system is described. The inverted high voltage structure of the gun permits a compact and simple design. Test results demonstrate that the load lock system provides a reliable way to achieve high quantum efficiency of the photocathode in a high voltage device. ((orig.))

  14. Integrated reconfigurable high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger

    2015-01-01

    In this paper a high-voltage transmitting circuit aimed for capacitive micromachined ultrasonic transducers (CMUTs) used in scanners for medical applications is designed and implemented in a 0.35 μm high-voltage CMOS process. The transmitting circuit is reconfigurable externally making it able...... to drive a wide variety of CMUTs. The transmitting circuit can generate several pulse shapes with voltages up to 100 V, maximum pulse range of 50 V, frequencies up to 5 MHz and different driving slew rates. Measurements are performed on the circuit in order to assess its functionality and power consumption...... performance. The design occupies an on-chip area of 0.938 mm2 and the power consumption of a 128-element transmitting circuit array that would be used in an portable ultrasound scanner is found to be a maximum of 181 mW....

  15. A Flexible Three-in-One Microsensor for Real-Time Monitoring of Internal Temperature, Voltage and Current of Lithium Batteries.

    Science.gov (United States)

    Lee, Chi-Yuan; Peng, Huan-Chih; Lee, Shuo-Jen; Hung, I-Ming; Hsieh, Chien-Te; Chiou, Chuan-Sheng; Chang, Yu-Ming; Huang, Yen-Pu

    2015-05-19

    Lithium batteries are widely used in notebook computers, mobile phones, 3C electronic products, and electric vehicles. However, under a high charge/discharge rate, the internal temperature of lithium battery may rise sharply, thus causing safety problems. On the other hand, when the lithium battery is overcharged, the voltage and current may be affected, resulting in battery instability. This study applies the micro-electro-mechanical systems (MEMS) technology on a flexible substrate, and develops a flexible three-in-one microsensor that can withstand the internal harsh environment of a lithium battery and instantly measure the internal temperature, voltage and current of the battery. Then, the internal information can be fed back to the outside in advance for the purpose of safety management without damaging the lithium battery structure. The proposed flexible three-in-one microsensor should prove helpful for the improvement of lithium battery design or material development in the future.

  16. High-voltage direct-current circuit breakers

    International Nuclear Information System (INIS)

    Yoshioka, Y.; Hirasawa, K.

    1991-01-01

    This paper reports that in 1954 the first high-voltage direct-current (HVDC) transmission system was put into operation between Gotland and the mainland of Sweden. Its system voltage and capacity were 100 kV and 20 MW, respectively. Since then many HVDC transmission systems have been planned, constructed, or commissioned in more than 30 places worldwide, and their total capacity is close to 40 GW. Most systems commissioned to date are two-terminal schemes, and HVDC breakers are not yet used in the high-potential main circuit of those systems, because the system is expected to perform well using only converter/inverter control even at a fault stage of the transmission line. However, even in a two-terminal scheme there are not a few merits in using an HVDC breaker when the system has two parallel transmission lines, that is, when it is a double-circuit system

  17. Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

    Science.gov (United States)

    Cai, Yuanji; Guan, Yonggang; Liu, Weidong

    2017-06-01

    Transient enclosure voltage (TEV), which is a phenomenon induced by the inner dielectric breakdown of SF6 during disconnector operations in a gas-insulated switchgear (GIS), may cause issues relating to shock hazard and electromagnetic interference to secondary equipment. This is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage (UHV) substations. In this paper, the statistical characteristics of TEV at UHV level are collected from field experiments, and are analyzed and compared to those from a repeated strike process. The TEV waveforms during disconnector operations are recorded by a self-developed measurement system first. Then, statistical characteristics, such as the pulse number, duration of pulses, frequency components, magnitude and single pulse duration, are extracted. The transmission line theory is introduced to analyze the TEV and is validated by the experimental results. Finally, the relationship between the TEV and the repeated strike process is analyzed. This proves that the pulse voltage of the TEV is proportional to the corresponding breakdown voltage. The results contribute to the definition of the standard testing waveform of the TEV, and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

  18. Design of auto-control high-voltage control system of pulsed neutron generator

    International Nuclear Information System (INIS)

    Lv Juntao

    2008-01-01

    It is difficult to produce multiple anode controlling time sequences under different logging mode for the high-voltage control system of the conventional pulsed neutron generator. It is also difficult realize sequential control among anode high-voltage, filament power supply and target voltage to make neutron yield stable. To these problems, an auto-control high-voltage system of neutron pulsed generator was designed. It not only can achieve anode high-voltage double blast time sequences, which can measure multiple neutron blast time sequences such as Σ, activated spectrum, etc. under inelastic scattering mode, but also can realize neutron generator real-time measurement of multi-state parameters and auto-control such as target voltage pulse width modulation (PWM), filament current, anode current, etc., there by it can produce stable neutron yield and realize stable and accurate measurement of the pulsed neutron full spectral loging tool. (authors)

  19. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  20. High voltage switch triggered by a laser-photocathode subsystem

    Science.gov (United States)

    Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

    2013-01-08

    A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

  1. BEHAVIOUR OF BACKFILL MATERIALS FOR ELECTRICAL GROUNDING SYSTEMS UNDER HIGH VOLTAGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. C. LIM

    2015-06-01

    Full Text Available Backfill materials like Bentonite and cement are effective in lowering grounding resistance of electrodes for a considerable period. During lightning, switching impulses and earth fault occurrences in medium and high voltage networks, the grounding system needs to handle extremely high currents either for a short duration or prolonged period respectively. This paper investigates the behaviour of bentonite, cement and sand under impulse and alternating high voltage (50Hz conditions. Fulguritic-formation was observed in all materials under alternating high voltage. The findings reveal that performance of grounding systems under high voltage conditions may significantly change from the outcomes anticipated at design stage.

  2. High voltage calibration of the TANSY-KM5 neutron detectors

    International Nuclear Information System (INIS)

    Grosshoeg, G.; Belle, P. van; Wilson, D.

    1996-11-01

    We have developed a procedure for the high voltage calibration of the TANSY neutron detectors. The procedure is based on the work done during the construction of the spectrometer. A program is written for the measurement of the sensitivity of the neutron detectors as a function of the high voltage. The data are transferred to a PC for evaluation. We use a Cobalt source for the calibration. With the PC the voltage corresponding to the effective Compton edge is found. The voltage settings for the neutron detectors are calculated and stored in a file suitable for input to a program that is used to control the instrument. A measurement is reported that shows that the reproducibility of the measurement is good. 4 refs

  3. Lithium-Ion Electrolytes with Improved Safety Tolerance to High Voltage Systems

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor); Prakash, Surya G. (Inventor); Krause, Frederick C. (Inventor)

    2015-01-01

    The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

  4. Understanding local degradation of cycled Ni-rich cathode materials at high operating temperature for Li-ion batteries

    Science.gov (United States)

    Hwang, Sooyeon; Kim, Dong Hyun; Chung, Kyung Yoon; Chang, Wonyoung

    2014-09-01

    We utilize transmission electron microscopy in conjunction with electron energy loss spectroscopy to investigate local degradation that occurs in LixNi0.8Co0.15Al0.05O2 cathode materials (NCA) after 30 cycles with cutoff voltages of 4.3 V and 4.8 V at 55 °C. NCA has a homogeneous crystallographic structure before electrochemical reactions; however, we observed that 30 cycles of charge/discharge reactions induced inhomogeneity in the crystallographic and electronic structures and also introduced porosity particularly at surface area. These changes were more noticeable in samples cycled with higher cutoff voltage of 4.8 V. Effect of operating temperature was further examined by comparing electronic structures of oxygen of the NCA particles cycled at both room temperature and 55 °C. The working temperature has a greater impact on the NCA cathode materials at a cutoff voltage of 4.3 V that is the practical the upper limit voltage in most applications, while a cutoff voltage of 4.8 V is high enough to cause surface degradation even at room temperature.

  5. Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness

    International Nuclear Information System (INIS)

    Rong-Hua, Li; Ying-Quan, Peng; Chao-Zhu, Ma; Run-Sheng, Wang; Hong-Wei, Xie; Ying, Wang; Wei-Min, Meng

    2010-01-01

    We numerically investigate the effects of the exciton generation rate G, temperature T, the active layer thickness d and the position of LUMO level E L related to the cathode work function W c at a given energy gap on the open-circuit voltage V oc of single layer organic solar cells with Schottky contact. It is demonstrated that open-circuit voltage increases concomitantly with the decreasing cathode work function W c for given anode work functions and exciton generation rates. In the case of given cathode and anode work functions, the open-circuit voltage first increases with the exciton generation rate and then reaches a saturation value, which equals to the built-in voltage. Additionally, it is worth noting that a significant improvement to V oc could be made by selecting an organic material which has a relative high LUMO level (low |E L | value). However, V oc decreases as the temperature increases, and the decreasing rate reduces with the enhancement of exciton generation rate. Our study also shows that it is of no benefit to improve the open-circuit voltage by increasing the device thickness because of an enhanced charge recombination in thicker devices. (cross-disciplinary physics and related areas of science and technology)

  6. A microcontroller application as X-ray machine's high voltage controller

    International Nuclear Information System (INIS)

    Wiranto Budi Santoso; Beny Syawaludin

    2010-01-01

    A micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x-ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive a stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-8051 compiler. The test results show that the stepper motor could rotate according to an input value (author)

  7. Advances in high voltage engineering

    CERN Document Server

    Haddad, A

    2005-01-01

    This book addresses the very latest research and development issues in high voltage technology and is intended as a reference source for researchers and students in the field, specifically covering developments throughout the past decade. This unique blend of expert authors and comprehensive subject coverage means that this book is ideally suited as a reference source for engineers and academics in the field for years to come.

  8. Compact, Lightweight, High Voltage Propellant Isolators, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — TA&T, Inc. proposes an enabling fabrication process for high voltage isolators required in high power solar electric and nuclear electric propulsion (SEP and...

  9. Calibration of the ISOLDE acceleration voltage using a high-precision voltage divider and applying collinear fast beam laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krieger, A., E-mail: kriegea@uni-mainz.d [Institut fuer Kernchemie, Johannes Gutenberg, Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); Geppert, Ch. [Institut fuer Kernchemie, Johannes Gutenberg, Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Catherall, R. [CERN, CH-1211 Geneve 23 (Switzerland); Hochschulz, F. [Institut fuer Kernphysik, Universitaet Muenster, 48149 Muenster (Germany); Kraemer, J.; Neugart, R. [Institut fuer Kernchemie, Johannes Gutenberg, Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); Rosendahl, S. [Institut fuer Kernphysik, Universitaet Muenster, 48149 Muenster (Germany); Schipper, J.; Siesling, E. [CERN, CH-1211 Geneve 23 (Switzerland); Weinheimer, Ch. [Institut fuer Kernphysik, Universitaet Muenster, 48149 Muenster (Germany); Yordanov, D.T. [Max-Planck-Institut fuer Kernphysik, 69117 Heidelberg (Germany); Noertershaeuser, W. [Institut fuer Kernchemie, Johannes Gutenberg, Universitaet Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany)

    2011-03-11

    A high-voltage divider with accuracy at the ppm level and collinear laser spectroscopy were used to calibrate the high-voltage installation at the radioactive ion beam facility ISOLDE at CERN. The accurate knowledge of this voltage is particularly important for collinear laser spectroscopy measurements. Beam velocity measurements using frequency-comb based collinear laser spectroscopy agree with the new calibration. Applying this, one obtains consistent results for isotope shifts of stable magnesium isotopes measured using collinear spectroscopy and laser spectroscopy on laser-cooled ions in a trap. The long-term stability and the transient behavior during recovery from a voltage dropout were investigated for the different power supplies currently applied at ISOLDE.

  10. Fast response double series resonant high-voltage DC-DC converter

    International Nuclear Information System (INIS)

    Lee, S S; Iqbal, S; Kamarol, M

    2012-01-01

    In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

  11. Effect of unbalanced voltage on windings temperature, operational life and load carrying capacity of induction machine

    Energy Technology Data Exchange (ETDEWEB)

    Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Street 83, 81-225 Gdynia (Poland)

    2008-04-15

    This paper investigates the influence of the CVUF angle on the windings temperature rise and the derating factor of an induction machine supplied with unbalanced voltage. The effect of simultaneous voltage unbalance and harmonics on its operational life is analyzed as well. The results of calculations and experimental investigations are presented for two induction cage machines of rated power 3 and 5.5 kW. (author)

  12. Reversible voltage dependent transition of abnormal and normal bipolar resistive switching.

    Science.gov (United States)

    Wang, Guangyu; Li, Chen; Chen, Yan; Xia, Yidong; Wu, Di; Xu, Qingyu

    2016-11-14

    Clear understanding the mechanism of resistive switching is the important prerequisite for the realization of high performance nonvolatile resistive random access memory. In this paper, binary metal oxide MoO x layer sandwiched by ITO and Pt electrodes was taken as a model system, reversible transition of abnormal and normal bipolar resistive switching (BRS) in dependence on the maximum voltage was observed. At room temperature, below a critical maximum voltage of 2.6 V, butterfly shaped I-V curves of abnormal BRS has been observed with low resistance state (LRS) to high resistance state (HRS) transition in both polarities and always LRS at zero field. Above 2.6 V, normal BRS was observed, and HRS to LRS transition happened with increasing negative voltage applied. Temperature dependent I-V measurements showed that the critical maximum voltage increased with decreasing temperature, suggesting the thermal activated motion of oxygen vacancies. Abnormal BRS has been explained by the partial compensation of electric field from the induced dipoles opposite to the applied voltage, which has been demonstrated by the clear amplitude-voltage and phase-voltage hysteresis loops observed by piezoelectric force microscopy. The normal BRS was due to the barrier modification at Pt/MoO x interface by the accumulation and depletion of oxygen vacancies.

  13. Current–voltage characteristics of high-voltage 4H-SiC p{sup +}–n{sub 0}–n{sup +} diodes in the avalanche breakdown mode

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, P. A., E-mail: Pavel.Ivanov@mail.ioffe.ru; Potapov, A. S.; Samsonova, T. P.; Grekhov, I. V. [Ioffe Physical–Technical Institute (Russian Federation)

    2017-03-15

    p{sup +}–n{sub 0}–n{sup +} 4H-SiC diodes with homogeneous avalanche breakdown at 1860 V are fabricated. The pulse current–voltage characteristics are measured in the avalanche-breakdown mode up to a current density of 4000 A/cm{sup 2}. It is shown that the avalanche-breakdown voltage increases with increasing temperature. The following diode parameters are determined: the avalanche resistance (8.6 × 10{sup –2} Ω cm{sup 2}), the electron drift velocity in the n{sub 0} base at electric fields higher than 10{sup 6} V/cm (7.8 × 10{sup 6} cm/s), and the relative temperature coefficient of the breakdown voltage (2.1 × 10{sup –4} K{sup –1}).

  14. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  15. A Flexible Three-in-One Microsensor for Real-Time Monitoring of Internal Temperature, Voltage and Current of Lithium Batteries

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2015-05-01

    Full Text Available Lithium batteries are widely used in notebook computers, mobile phones, 3C electronic products, and electric vehicles. However, under a high charge/discharge rate, the internal temperature of lithium battery may rise sharply, thus causing safety problems. On the other hand, when the lithium battery is overcharged, the voltage and current may be affected, resulting in battery instability. This study applies the micro-electro-mechanical systems (MEMS technology on a flexible substrate, and develops a flexible three-in-one microsensor that can withstand the internal harsh environment of a lithium battery and instantly measure the internal temperature, voltage and current of the battery. Then, the internal information can be fed back to the outside in advance for the purpose of safety management without damaging the lithium battery structure. The proposed flexible three-in-one microsensor should prove helpful for the improvement of lithium battery design or material development in the future.

  16. High energy density battery lithium thionyl chloride improved reverse voltage design

    Science.gov (United States)

    Zolla, A. E.

    1981-12-01

    A test program was conducted to demonstrate safety under voltage reversal conditions of the Altus 1400 AH HEDB cell. Eight cells of an improve Anode Grid Design, all cathode (carbon) limited, were forced discharged for 150% of their normal capacity. Minor design variations were tested at 6 amp, 20 C and 12 amp, 0 C with a lithium reference electrode and separate monitoring of current through the internal reverse voltage current shunt feature. There were no ventings and no appreciable increase in cell temperature or internal pressure.

  17. System for high-voltage control detectors with large number photomultipliers

    International Nuclear Information System (INIS)

    Donskov, S.V.; Kachanov, V.A.; Mikhajlov, Yu.V.

    1985-01-01

    A simple and inexpensive on-line system for hihg-voltage control which is designed for detectors with a large number of photomultipliers is developed and manufactured. It has been developed for the GAMC type hodoscopic electromagnetic calorimeters, comprising up to 4 thousand photomultipliers. High voltage variation is performed by a high-speed potentiometer which is rotated by a microengine. Block-diagrams of computer control electronics are presented. The high-voltage control system has been used for five years in the IHEP and CERN accelerator experiments. The operation experience has shown that it is quite simple and convenient in operation. In case of about 6 thousand controlled channels in both experiments no potentiometer and microengines failures were observed

  18. Self-aligned photolithography for the fabrication of fully transparent high-voltage devices

    Science.gov (United States)

    Zhang, Yonghui; Mei, Zengxia; Huo, Wenxing; Wang, Tao; Liang, Huili; Du, Xiaolong

    2018-05-01

    High-voltage devices, working in the range of hundreds of volts, are indispensable elements in the driving or readout circuits for various kinds of displays, integrated microelectromechanical systems and x-ray imaging sensors. However, the device performances are found hardly uniform or repeatable due to the misalignment issue, which are extremely common for offset drain high-voltage devices. To resolve this issue, this article reports a set of self-aligned photolithography technology for the fabrication of high-voltage devices. High-performance fully-transparent high-voltage thin film transistors, diodes and logic inverters are successfully fabricated with this technology. Unlike other self-aligned routes, opaque masks are introduced on the backside of the transparent substrate to facilitate proximity exposure method. The photolithography process is simulated and analyzed with technology computer aided design simulation to explain the working principle of the proximity exposure method. The substrate thickness is found to be vital for the implementation of this technology based on both simulation and experimental results. The electrical performance of high-voltage devices is dependent on the offset length, which can be delicately modulated by changing the exposure dose. The presented self-aligned photolithography technology is proved to be feasible in high-voltage circuits, demonstrating its huge potential in practical industrial applications.

  19. Design Comparison of Autonomous High Voltage Driving System for DEAP Actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Pittini, Riccardo; Zhang, Zhe

    2014-01-01

    As a new type of smart material, the Dielectric Electro Active Polymer (DEAP) is introduced in terms of configuration, working principle and potential applications. The design of an autonomous high voltage driving system for DEAP actuator is investigated. The system configuration and the design...... methodology of a high voltage converter are discussed in detail. Based on the heating valve application, three different high voltage converter solutions have been proposed. The different proposals have been compared in terms of energy loss, volume and cost. Finally, the design selection suggestions...

  20. Enhanced Local Grid Voltage Support Method for High Penetration of Distributed Generators

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Rodriguez, Pedro

    2011-01-01

    Grid voltage rise and thermal loading of network components are the most remarkable barriers to allow high number of distributed generator (DG) connections on the medium voltage (MV) and low voltage (LV) electricity networks. The other barriers such as grid power quality (harmonics, voltage...

  1. Measurement of high-temperature spectral emissivity using integral blackbody approach

    Science.gov (United States)

    Pan, Yijie; Dong, Wei; Lin, Hong; Yuan, Zundong; Bloembergen, Pieter

    2016-11-01

    Spectral emissivity is one of the most critical thermophysical properties of a material for heat design and analysis. Especially in the traditional radiation thermometry, normal spectral emissivity is very important. We developed a prototype instrument based upon an integral blackbody method to measure material's spectral emissivity at elevated temperatures. An optimized commercial variable-high-temperature blackbody, a high speed linear actuator, a linear pyrometer, and an in-house designed synchronization circuit was used to implemented the system. A sample was placed in a crucible at the bottom of the blackbody furnace, by which the sample and the tube formed a simulated reference blackbody which had an effective total emissivity greater than 0.985. During the measurement, a pneumatic cylinder pushed a graphite rode and then the sample crucible to the cold opening within hundreds of microseconds. The linear pyrometer was used to monitor the brightness temperature of the sample surface, and the corresponding opto-converted voltage was fed and recorded by a digital multimeter. To evaluate the temperature drop of the sample along the pushing process, a physical model was proposed. The tube was discretized into several isothermal cylindrical rings, and the temperature of each ring was measurement. View factors between sample and rings were utilized. Then, the actual surface temperature of the sample at the end opening was obtained. Taking advantages of the above measured voltage signal and the calculated actual temperature, normal spectral emissivity under the that temperature point was obtained. Graphite sample at 1300°C was measured to prove the validity of the method.

  2. Computer applications: Automatic control system for high-voltage accelerator

    International Nuclear Information System (INIS)

    Bryukhanov, A.N.; Komissarov, P.Yu.; Lapin, V.V.; Latushkin, S.T.. Fomenko, D.E.; Yudin, L.I.

    1992-01-01

    An automatic control system for a high-voltage electrostatic accelerator with an accelerating potential of up to 500 kV is described. The electronic apparatus on the high-voltage platform is controlled and monitored by means of a fiber-optic data-exchange system. The system is based on CAMAC modules that are controlled by a microprocessor crate controller. Data on accelerator operation are represented and control instructions are issued by means of an alphanumeric terminal. 8 refs., 6 figs

  3. Technical and economic considerations of extra high voltage power transmission

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. High-voltage variable-duration pulse generator

    International Nuclear Information System (INIS)

    Anisimova, T.E.; Akkuratov, E.V.; Gromovenko, V.M.; Nikonov, Yu.P.; Malinin, A.N.

    1988-01-01

    A high-voltage generator is described that allows pulse duration tau to be varied within wide limits and has high efficiency (at least 50% for tau = 0.5 tau/sub max/) and an amplitude of up to 5 kV, a repetition frequency of up to 200 Hz,and a variable duration of 0-30 μsec. The generator is used in the controller of an electron accelerator

  5. Quench Detection and Protection for High Temperature Superconducting Transformers by Using the Active Power Method

    Science.gov (United States)

    Nanato, N.; Kobayashi, Y.

    AC high temperature superconducting (HTS) coils have been developed for transformers, motors and so on. Quench detection and protection system are essential for safety operations of the AC HTS facilities. The balance voltage method is universally used for the quench detection and protection, however especially for AC operations, the method has risks in terms of high voltage sparks. Because the method needs a voltage tap soldered to a midpoint of the coil winding and the AC HTS facilities generally operate at high voltages and therefore high voltage sparks may occur at the midpoint with no insulation. We have proposed the active power method for the quench detection and protection. The method requires no voltage tap on the midpoint of the coil winding and therefore it has in-built effectiveness for the AC HTS facilities. In this paper, we show that the method can detect the quench in an HTS transformer and moreover our proposed quench protection circuits which consist of thyristors are simple and useful for the AC HTS facilities.

  6. High-voltage polymeric insulated cables

    Energy Technology Data Exchange (ETDEWEB)

    Ross, A

    1987-01-01

    Reviews developments in high-voltage (here defined as 25 kV, 66 kV and 132 kV) polymeric insulated cables in the UK over the period 1979-1986, with particular reference to the experience of the Eastern Electricity Board. Outlines the background to the adoption of XPLE-insulated solid cable, and the design, testing, terminations, jointing and costs of 25 kV, 66 kV and 132 kV cables.

  7. Low Voltage, High-Q SOI MEMS Varactors for RF Applications

    DEFF Research Database (Denmark)

    Yalcinkaya, Arda Deniz; Jensen, Søren; Hansen, Ole

    2003-01-01

    A micro electromechanical tunable capacitor with a low control voltage, a wide tuning range and high electrical quality factor is presented with detailed characterizations. A 50μm thick single-crystalline silicon layer was etched using deep reactive ion etching (DRIE) for obtaining high-aspect ra...... is a suitable passive component to be used in band-pass filtering, voltage controlled oscillator or impedance matching applications on the very high frequency(VHF) and ultra high frequency (UHF) bands....

  8. High voltage short plus generation based on avalanche circuit

    International Nuclear Information System (INIS)

    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)

  9. A high-voltage pulse generator for corona plasma generation

    NARCIS (Netherlands)

    Yan, K.; Heesch, van E.J.M.; Pemen, A.J.M.; Huijbrechts, P.A.H.J.; Gompel, van F.M.; Leuken, van H.E.M.; Matyas, Z.

    2002-01-01

    This paper discusses a high-voltage pulse generator for producing corona plasma. The generator consists of three resonant charging circuits, a transmission line transformer, and a triggered spark-gap switch. Voltage pulses in the order of 30-100 kV with a rise time of 10-20 ns, a pulse duration of

  10. On-chip high-voltage generator design design methodology for charge pumps

    CERN Document Server

    Tanzawa, Toru

    2016-01-01

    This book provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.  This new edition includes a variety of useful updates, including coverage of power efficiency and comprehensive optimization methodologies for DC-DC voltage multipliers, modeling of extremely low voltage Dickson charge pumps, and modeling and optimum design of AC-DC switched-capacitor multipliers for energy harvesting and power transfer for RFID.

  11. Wide-bandgap high-mobility ZnO thin-film transistors produced at room temperature

    International Nuclear Information System (INIS)

    Fortunato, Elvira M.C.; Barquinha, Pedro M.C.; Pimentel, Ana C.M.B.G.; Goncalves, Alexandra M.F.; Marques, Antonio J.S.; Martins, Rodrigo F.P.; Pereira, Luis M.N.

    2004-01-01

    We report high-performance ZnO thin-film transistor (ZnO-TFT) fabricated by rf magnetron sputtering at room temperature with a bottom gate configuration. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 19 V, a saturation mobility of 27 cm 2 /V s, a gate voltage swing of 1.39 V/decade and an on/off ratio of 3x10 5 . The ZnO-TFT presents an average optical transmission (including the glass substrate) of 80% in the visible part of the spectrum. The combination of transparency, high mobility, and room-temperature processing makes the ZnO-TFT a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics

  12. Towards low-voltage organic thin film transistors (OTFTs with solution-processed high-k dielectric and interface engineering

    Directory of Open Access Journals (Sweden)

    Yaorong Su

    2015-11-01

    Full Text Available Although impressive progress has been made in improving the performance of organic thin film transistors (OTFTs, the high operation voltage resulting from the low gate capacitance density of traditional SiO2 remains a severe limitation that hinders OTFTs'development in practical applications. In this regard, developing new materials with high-k characteristics at low cost is of great scientific and technological importance in the area of both academia and industry. Here, we introduce a simple solution-based technique to fabricate high-k metal oxide dielectric system (ATO at low-temperature, which can be used effectively to realize low-voltage operation of OTFTs. On the other hand, it is well known that the properties of the dielectric/semiconductor and electrode/semiconductor interfaces are crucial in controlling the electrical properties of OTFTs. By optimizing the above two interfaces with octadecylphosphonic acid (ODPA self-assembled monolayer (SAM and properly modified low-cost Cu, obviously improved device performance is attained in our low-voltage OTFTs. Further more, organic electronic devices on flexible substrates have attracted much attention due to their low-cost, rollability, large-area processability, and so on. Basing on the above results, outstanding electrical performance is achieved in flexible devices. Our studies demonstrate an effective way to realize low-voltage, high-performance OTFTs at low-cost.

  13. The Thermal Regime Around Buried Submarine High-Voltage Cables

    Science.gov (United States)

    Emeana, C. J.; Dix, J.; Henstock, T.; Gernon, T.; Thompson, C.; Pilgrim, J.

    2015-12-01

    The expansion of offshore renewable energy infrastructure and the desire for "trans-continental shelf" power transmission, all require the use of submarine High Voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70oC and are typically buried at depths of 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the thermal properties of near surface shelf sediments are poorly understood and this increases the uncertainty in determining the required cable current ratings, cable reliability and the potential effects on the sedimentary environments. We present temperature measurements from a 2D laboratory experiment, designed to represent a buried, submarine HV cable. We used a large (2.5 m-high) tank, filled with water-saturated ballotini and instrumented with 120 thermocouples, which measured the time-dependent 2D temperature distributions around the heat source. The experiments use a buried heat source to represent a series of realistic cable surface temperatures with the aim for identifying the thermal regimes generated within typical non-cohesive shelf sediments: coarse silt, fine sand and very coarse sand. The steady state heat flow regimes, and normalised and radial temperature distributions were assessed. Our results show that at temperatures up to 60°C above ambient, the thermal regimes are conductive for the coarse silt sediments and convective for the very coarse sand sediments even at 7°C above ambient. However, the heat flow pattern through the fine sand sediment shows a transition from conductive to convective heat flow at a temperature of approximately 20°C above ambient. These findings offer an important new understanding of the thermal regimes associated with submarine HV cables buried in different substrates and has huge impacts on cable ratings as the IEC 60287 standard only considers conductive heat flow as well as other potential near surface impacts.

  14. Environmental and biotechnological applications of high-voltage pulsed discharges in water

    International Nuclear Information System (INIS)

    Sato, Masayuki

    2008-01-01

    A high-voltage pulse has wide application in fields such as chemistry, physics and biology and their combinations. The high-voltage pulse forms two kinds of physical processes in water, namely (a) a pulsed electric field (PEF) in the parallel electrode configuration and (b) plasma generation by a pulsed discharge in the water phase with a concentrated electric field. The PEF can be used for inactivation of bacteria in liquid foods as a non-thermal process, and the underwater plasma is applicable not only for the decomposition of organic materials in water but also for biological treatment of wastewater. These discharge states are controlled mainly by the applied pulse voltage and the electrode shape. Some examples of environmental and biotechnological applications of a high-voltage pulse are reviewed.

  15. High-voltage test and training of plastic streamer tubes for the DELPHI hadron calorimeter

    International Nuclear Information System (INIS)

    Alekseev, G.D.; Cellar, S.; Khomenko, B.A.; Korytov, A.V.; Kulinich, P.A.; Micelmacher, G.V.; Sedykh, Yu.V.; Toledo, R.

    1987-01-01

    The results of high-voltage test and training of plastic streamer tubes of the DELPHI hadron calorimeter are presented. The testing technique is considered in detail. The equipment for high-voltage training consists of a mini-computer, CAMAC-electronics, a controllable high-voltage supply and a digital ampermeter. The experimental results shows that high-voltage training of streamer tubes improves their characteristics. The value of dark current decreased up to 1 μA. The operational voltage range increased by a value more than 300 V

  16. LIMIT SOLUTIONS OF EQUATIONS OF A DC HIGH-VOLTAGE CASCADE GENERATOR

    Directory of Open Access Journals (Sweden)

    V. O. Brzhezitsky

    2015-04-01

    Full Text Available In the paper the issue of calculating the high voltage cascade mode oscillator with a nonlinear load using the analytical method under different conditions of selection values of its components is presented. The peculiarity of the method of the study is that during multivariate calculations output parameters load generator remain unchanged. For high-voltage cascade direct current power found conditions under which can be significantly reduced high capacity capacitors cascade generator. The calculations show that acceptable for practical applications of high-voltage characteristics of cascade generators can be achieved with substantial reduction of the volume of their constituents, and thus substantial decline in their value.

  17. A novel high voltage start up circuit for an integrated switched mode power supply

    Energy Technology Data Exchange (ETDEWEB)

    Hu Hao; Chen Xingbi, E-mail: huhao21@uestc.edu.c [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2010-09-15

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions. (semiconductor devices)

  18. High Voltage Hybrid Electric Propulsion - Multilayered Functional Insulation System (MFIS) NASA-GRC

    Science.gov (United States)

    Lizcano, M.

    2017-01-01

    High power transmission cables pose a key challenge in future Hybrid Electric Propulsion Aircraft. The challenge arises in developing safe transmission lines that can withstand the unique environment found in aircraft while providing megawatts of power. High voltage AC, variable frequency cables do not currently exist and present particular electrical insulation challenges since electrical arcing and high heating are more prevalent at higher voltages and frequencies. Identifying and developing materials that maintain their dielectric properties at high voltage and frequencies is crucial.

  19. Wideband Electrostatic Vibration Energy Harvester (e-VEH) Having a Low Start-Up Voltage Employing a High-Voltage Integrated Interface

    International Nuclear Information System (INIS)

    Dudka, A; Galayko, D; Basset, P; Cottone, F; Blokhina, E

    2013-01-01

    This paper reports on an electrostatic Vibration Energy Harvester (e-VEH) system, for which the energy conversion process is initiated with a low bias voltage and is compatible with wideband stochastic external vibrations. The system employs the auto-synchronous conditioning circuit topology with the use of a novel dedicated integrated low-power high-voltage switch that is needed to connect the charge pump and flyback – two main parts of the used conditioning circuit. The proposed switch is designed and implemented in AMS035HV CMOS technology. Thanks to the proposed switch device, which is driven with a low-voltage ground-referenced logic, the e-VEH system may operate within a large voltage range, from a pre-charge low voltage up to several tens volts. With such a high-voltage e-VEH operation, it is possible to obtain a strong mechanical coupling and a high rate of vibration energy conversion. The used transducer/resonator device is fabricated with a batch-processed MEMS technology. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110–170 Hz, up to 0.75 μW of net electrical power has been harvested with our system. This work presents an important milestone in the challenge of designing a fully integrated smart conditioning interface for the capacitive e-VEHs

  20. Technical and economic considerations of extra high voltage power transmission

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. High-voltage therapy of carcinoma of the prostate

    International Nuclear Information System (INIS)

    Schnorr, D.; Kelly, L.U.; Guddat, H.M.; Schubert, J.; Gorski, J.; Schorcht, J.; Mau, S.; Wehnert, J.; Medizinische Akademie, Dresden

    1983-01-01

    High-voltage therapy is becoming increasingly important as a form of individual differential therapy of carcinoma of the prostate. Around 40% of all patients with a diagnosis of carcinoma of the prostate can be treated with high-voltage therapy. The precondition is the absence of bone and soft tissue metastases and of juxtaregional lymph node metastases. Individual carcinoma therapy is based on pre therapeutic tumor classification according to the TNM system. The 5-year survival rates are presented from a retrospective study carried out using primary radiation monotherapy and a combined hormone and radiation therapy; these figures were calculated by the life-table method. The study revealed no significant differences between the two forms of therapy as regards 5-year survival rates. The 5-year survival rates of all patients of the classifications T 0 -T 3 N/sub x/-N 2 M 0 irradiated (n: 198) (72% +- 11% for hormone plus radiation therapy and 74% +- 11% for radiation monotherapy) did not differ greatly from those of a normal male population of the same age (77%). High-voltage therapy of carcinoma of the prostate can thus be classified as a curative method of treatment. (author)

  2. High voltage pulsed cable design: a practical example

    International Nuclear Information System (INIS)

    Kewish, R.W. Jr.; Boicourt, G.P.

    1979-01-01

    The design of optimum high voltage pulse cable is difficult because very little emperical data are available on performance in pulsed applications. This paper follows the design and testing of one high voltage pulse cable, 40/100 trigger cable. The design was based on an unproven theory and the impressive outcome lends support to the theory. The theory is outlined and it is shown that there exists an inductance which gives a cable of minimum size for a given maximum stress. Test results on cable manufactured according to the design are presented and compared with the test results on the cable that 40/100 replaces

  3. High voltage pulsed cable design: a practical example

    Energy Technology Data Exchange (ETDEWEB)

    Kewish, R.W. Jr.; Boicourt, G.P.

    1979-01-01

    The design of optimum high voltage pulse cable is difficult because very little emperical data are available on performance in pulsed applications. This paper follows the design and testing of one high voltage pulse cable, 40/100 trigger cable. The design was based on an unproven theory and the impressive outcome lends support to the theory. The theory is outlined and it is shown that there exists an inductance which gives a cable of minimum size for a given maximum stress. Test results on cable manufactured according to the design are presented and compared with the test results on the cable that 40/100 replaces.

  4. Understanding local degradation of cycled Ni-rich cathode materials at high operating temperature for Li-ion batteries

    International Nuclear Information System (INIS)

    Hwang, Sooyeon; Kim, Dong Hyun; Chung, Kyung Yoon; Chang, Wonyoung

    2014-01-01

    We utilize transmission electron microscopy in conjunction with electron energy loss spectroscopy to investigate local degradation that occurs in Li x Ni 0.8 Co 0.15 Al 0.05 O 2 cathode materials (NCA) after 30 cycles with cutoff voltages of 4.3 V and 4.8 V at 55 °C. NCA has a homogeneous crystallographic structure before electrochemical reactions; however, we observed that 30 cycles of charge/discharge reactions induced inhomogeneity in the crystallographic and electronic structures and also introduced porosity particularly at surface area. These changes were more noticeable in samples cycled with higher cutoff voltage of 4.8 V. Effect of operating temperature was further examined by comparing electronic structures of oxygen of the NCA particles cycled at both room temperature and 55 °C. The working temperature has a greater impact on the NCA cathode materials at a cutoff voltage of 4.3 V that is the practical the upper limit voltage in most applications, while a cutoff voltage of 4.8 V is high enough to cause surface degradation even at room temperature.

  5. Understanding local degradation of cycled Ni-rich cathode materials at high operating temperature for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sooyeon; Kim, Dong Hyun; Chung, Kyung Yoon; Chang, Wonyoung, E-mail: cwy@kist.re.kr [Center for Energy Convergence, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2014-09-08

    We utilize transmission electron microscopy in conjunction with electron energy loss spectroscopy to investigate local degradation that occurs in Li{sub x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathode materials (NCA) after 30 cycles with cutoff voltages of 4.3 V and 4.8 V at 55 °C. NCA has a homogeneous crystallographic structure before electrochemical reactions; however, we observed that 30 cycles of charge/discharge reactions induced inhomogeneity in the crystallographic and electronic structures and also introduced porosity particularly at surface area. These changes were more noticeable in samples cycled with higher cutoff voltage of 4.8 V. Effect of operating temperature was further examined by comparing electronic structures of oxygen of the NCA particles cycled at both room temperature and 55 °C. The working temperature has a greater impact on the NCA cathode materials at a cutoff voltage of 4.3 V that is the practical the upper limit voltage in most applications, while a cutoff voltage of 4.8 V is high enough to cause surface degradation even at room temperature.

  6. High voltage transmission lines studies with the use of artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Ekonomou, L. [A.S.PE.T.E. - School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece)

    2009-12-15

    The paper presents an alternative approach for the studies of high voltage transmission lines based on artificial intelligence and more specifically artificial neural networks (ANNs). In contrast to the existing conventional-analytical techniques and simulations which are using in the calculations empirical and/or approximating equations, this approach is based only on actual field data and actual measurements. The proposed approach is applied on high voltage transmission lines in order to calculate the lightning outages, on grounding systems in order to assess the grounding resistance and on high voltage transmission lines' polluted insulators in order to estimate the critical flashover voltage. The obtained results are very close to the actual ones for all three case studies, something which clearly implies that the ANN approach is well working and has an acceptable accuracy, constituting an additional tool of electric engineers. (author)

  7. 30 CFR 75.803 - Fail safe ground check circuits on high-voltage resistance grounded systems.

    Science.gov (United States)

    2010-07-01

    ... High-Voltage Distribution § 75.803 Fail safe ground check circuits on high-voltage resistance grounded systems. [Statutory Provisions] On and after September 30, 1970, high-voltage, resistance grounded systems... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fail safe ground check circuits on high-voltage...

  8. Contribution to high voltage matrix switches reliability

    International Nuclear Information System (INIS)

    Lausenaz, Yvan

    2000-01-01

    Nowadays, power electronic equipment requirements are important, concerning performances, quality and reliability. On the other hand, costs have to be reduced in order to satisfy the market rules. To provide cheap, reliability and performances, many standard components with mass production are developed. But the construction of specific products must be considered following these two different points: in one band you can produce specific components, with delay, over-cost problems and eventuality quality and reliability problems, in the other and you can use standard components in a adapted topologies. The CEA of Pierrelatte has adopted this last technique of power electronic conception for the development of these high voltage pulsed power converters. The technique consists in using standard components and to associate them in series and in parallel. The matrix constitutes high voltage macro-switch where electrical parameters are distributed between the synchronized components. This study deals with the reliability of these structures. It brings up the high reliability aspect of MOSFETs matrix associations. Thanks to several homemade test facilities, we obtained lots of data concerning the components we use. The understanding of defects propagation mechanisms in matrix structures has allowed us to put forwards the necessity of robust drive system, adapted clamping voltage protection, and careful geometrical construction. All these reliability considerations in matrix associations have notably allowed the construction of a new matrix structure regrouping all solutions insuring reliability. Reliable and robust, this product has already reaches the industrial stage. (author) [fr

  9. High voltage system design for the IUCF 300 KV electron cooling system

    International Nuclear Information System (INIS)

    Bertuccio, T.; Brown, B.; Donica, G.; Ellison, T.; Friesel, D.L.

    1985-01-01

    A summary of the electron beam high voltage system design for the IUCF Cooler now under construction, is presented. There are extremely stringent regulation requirements (about 10ppm) on the main high voltage power supply (-300 kVDC, 15 mA), and less stringent requirements on the gun anode power supply, in order to achieve the regulation needed to store beams in the IUCF Cooler with very low momentum spreads (Δp/p approx. = 2 x 10 -5 ). An overview of the main high voltage power supply (HVPS) specifications and design, as well as provisions and plans to improve the regulation are discussed. The electron collection system, modeled after the FNAL collector which was able to collect between 99.9% and 99.99% of the electron beam, is discussed along with the requirements of the associated power supplies. The designs of the high voltage acceleration structures and high voltage platform are discussed, as well as practical design considerations based upon experience with the Fermilab 120 keV electron cooling system

  10. High-temperature performance of gallium-nitride-based pin alpha-particle detectors grown on sapphire substrates

    Science.gov (United States)

    Zhu, Zhifu; Zhang, Heqiu; Liang, Hongwei; Tang, Bin; Peng, Xincun; Liu, Jianxun; Yang, Chao; Xia, Xiaochuan; Tao, Pengcheng; Shen, Rensheng; Zou, Jijun; Du, Guotong

    2018-06-01

    The temperature-dependent radiation-detection performance of an alpha-particle detector that was based on a gallium-nitride (GaN)-based pin structure was studied from 290 K to 450 K. Current-voltage-temperature measurements (I-V-T) of the reverse bias show the exponential dependence of leakage currents on the voltage and temperature. The current transport mechanism of the GaN-based pin diode from the reverse bias I-V fitting was analyzed. The temperature-dependent pulse-height spectra of the detectors were studied using an 241 Am alpha-particle source at a reverse bias of 10 V, and the peak positions shifted from 534 keV at 290 K to 490 keV at 450 K. The variation of full width at half maximum (FWHM) from 282 keV at 290 K to 292 keV at 450 K is almost negligible. The GaN-based pin detectors are highly promising for high-temperature environments up to 450 K.

  11. A high-voltage triggered pseudospark discharge experiment

    International Nuclear Information System (INIS)

    Ramaswamy, K.; Destler, W.W.; Rodgers, J.

    1996-01-01

    The design and execution of a pulsed high-voltage (350 endash 400 keV) triggered pseudospark discharge experiment is reported. Experimental studies were carried out to obtain an optimal design for stable and reliable pseudospark operation in a high-voltage regime (approx-gt 350 kV). Experiments were performed to determine the most suitable fill gas for electron-beam formation. The pseudospark discharge is initiated by a trigger mechanism involving a flashover between the trigger electrode and hollow cathode housing. Experimental results characterizing the electron-beam energy using the range-energy method are reported. Source size imaging was carried out using an x-ray pinhole camera and a novel technique using Mylar as a witness plate. It was experimentally determined that strong pinching occurred later in time and was associated with the lower-energy electrons. copyright 1996 American Institute of Physics

  12. Constant potential high-voltage generator

    International Nuclear Information System (INIS)

    Resnick, T.A.; Dupuis, W.A.; Palermo, T.

    1980-01-01

    An X-ray tube voltage generator with automatic stabilization circuitry is disclosed. The generator includes a source of pulsating direct current voltage such as from a rectified 3 phase transformer. This pulsating voltage is supplied to the cathode and anode of an X-ray tube and forms an accelerating potential for electrons within that tube. The accelerating potential is stabilized with a feedback signal which is provided by a feedback network. The network includes an error signal generator which compares an instantaneous accelerating potential with a preferred reference accelerating potential and generates an error function. This error function is transmitted to a control tube grid which in turn causes the voltage difference between X-ray tube cathode and anode to stabilize and thereby reduce the error function. In this way stabilized accelerating potentials are realized and uniform X-ray energy distributions produced. (Auth.)

  13. High-Field Quench Behavior and Protection of $Bi_2 Sr_2 Ca Cu_2 O_x$ Coils: Minimum and Maximum Quench Detection Voltages

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Tengming [Fermilab; Ye, Liyang [NCSU, Raleigh; Turrioni, Daniele [Fermilab; Li, Pei [Fermilab

    2015-01-01

    Small insert coils have been built using a multifilamentary Bi2Sr2CaCu2Ox round wire, and characterized in background fields to explore the quench behaviors and limits of Bi2Sr2CaCu2Ox superconducting magnets, with an emphasis on assessing the impact of slow normal zone propagation on quench detection. Using heaters of various lengths to initiate a small normal zone, a coil was quenched safely more than 70 times without degradation, with the maximum coil temperature reaching 280 K. Coils withstood a resistive voltage of tens of mV for seconds without quenching, showing the high stability of these coils and suggesting that the quench detection voltage shall be greater than 50 mV to not to falsely trigger protection. The hot spot temperature for the resistive voltage of the normal zone to reach 100 mV increases from ~40 K to ~80 K with increasing the operating wire current density Jo from 89 A/mm2 to 354 A/mm2 whereas for the voltage to reach 1 V, it increases from ~60 K to ~140 K, showing the increasing negative impact of slow normal zone propagation on quench detection with increasing Jo and the need to limit the quench detection voltage to < 1 V. These measurements, coupled with an analytical quench model, were used to access the impact of the maximum allowable voltage and temperature upon quench detection on the quench protection, assuming to limit the hot spot temperature to <300 K.

  14. 30 CFR 57.12071 - Movement or operation of equipment near high-voltage powerlines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Movement or operation of equipment near high-voltage powerlines. 57.12071 Section 57.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...-voltage powerlines. When equipment must be moved or operated near energized high-voltage powerlines (other...

  15. An Inexpensive Source of High Voltage

    Science.gov (United States)

    Saraiva, Carlos

    2012-01-01

    As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes. In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you…

  16. Tentative type test of a non-invasive high-voltage meter with respect to the quantity of practical peak voltage

    International Nuclear Information System (INIS)

    Peixoto, J.G.P.; Selbach, H.J.; Kramer, H.M.; Lange, B.

    2001-04-01

    In Working Group 3 of Sub-committee 62C of the international electrotechnical commission (IEC) a new project is underway [1] with the objective of specifying requirements for the performance characteristics of instruments for the non-invasive measurement of the X-ray tube voltage in diagnostic radiology. In this draft the X-ray tube voltage is specified in terms of the practical peak voltage [2]. The objective of the present work is to perform a tentative type test, based on the ''Requirements for Instruments for Non-invasive Measurements of the X-ray Tube Voltage'' defined in the IEC draft, with a commercially available non-invasive high-voltage meter. The instrument was modified so that the practical peak voltage can be measured. It is shown that the instrument, with the modifications made, is suitable for the non-invasive measurement of the practical peak voltage between 50 kV and 150 kV within the required limits of variation of the response. (orig.)

  17. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    Science.gov (United States)

    Teverovsky, Alexander A.

    2016-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  18. Determining the mode of high voltage breakdowns in vacuum devices

    International Nuclear Information System (INIS)

    Miller, H.C.; Furno, E.J.; Sturtz, J.P.

    1980-01-01

    Devices were constructed which were essentially vacuum diodes equipped with windows allowing observation of high voltage breakdowns. The waveform of the applied voltage was photographed, and the x-ray output was monitored to investigate electrical breakdown in these vacuum diodes. Results indicate that breakdowns may be divided into two types: (1) vacuum (interelectrode) breakdown - characterized by a diffuse moderately bright discharge, a relative slow and smooth voltage collapse, and a large burst of x-rays, and (2) surface (insulator) flashover - characterized by a bright discharge with a very bright filamentary core, a relatively fast and noisy voltage collapse and no x-ray burst. Useful information concerning the type of breakdown in a vacuum device can be obtained by monitoring the voltage (current) waveform and the x-ray output

  19. Cermet insert high voltage holdoff for ceramic/metal vacuum devices

    Science.gov (United States)

    Ierna, William F.

    1987-01-01

    An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

  20. Applications of passive remote surface acoustic wave sensors in high-voltage systems; Einsatz von passiven funkabfragbaren Oberflaechenwellensensoren in der elektrischen Energietechnik

    Energy Technology Data Exchange (ETDEWEB)

    Teminova, R

    2007-06-29

    Passive remote Surface Acoustic Wave (SAW) sensors have been applied e.g. as temperature, pressure or torque sensors. Their important advantages over standard methods are their passive operating principle, which allows operation without any power supply, as well as the wireless high-frequency signal transmission over distances up to about 10..15 m even through (non metallic) housings. These properties of SAW sensors particularly qualify them for applications in high voltage operational equipment. First experience was gained in a long time field test of surge arrester monitoring based on SAW temperature sensors in a German high-voltage substation. Now, this system has been further developed at Darmstadt University of Technology for other applications, the first of them being an overhead line (OHL) conductor temperature measurement, the second one a temperature monitoring system for of high-voltage disconnectors. After designing and building the sensors, extensive laboratory tests were carried out applying high-voltage, high-current and thermal stress in order to approve the suitability for the intended application. All these tests confirmed the assumption that SAW sensors, due to their passive working principle, are not affected at all by any kind of electrical, magnetic or thermal stress that may occur during service. The complete temperature sensor consists of three parts: a sensor chip, an antenna which receives and transmits the signal from and to the radar unit and a body for installation and for protection against environmental impact. One must find a good compromise between optimizing of thermal, dielectric and high-frequency characteristics and at the same time taking into consideration a simple installation. These requirements on the SAW sensors turned out to be difficult to coordinate. To achieve a high measuring precision is especially difficult. First, a new sensor for OHL application was developed. The OHL conductor temperature sensor had been optimized

  1. High-voltage integrated transmitting circuit with differential driving for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Færch, Kjartan Ullitz

    2016-01-01

    In this paper, a high-voltage integrated differential transmitting circuit for capacitive micromachined ultrasonic transducers (CMUTs) used in portable ultrasound scanners is presented. Due to its application, area and power consumption are critical and need to be minimized. The circuitry...... is designed and implemented in AMS 0.35 μ m high-voltage process. Measurements are performed on the fabricated integrated circuit in order to assess its performance. The transmitting circuit consists of a low-voltage control logic, pulse-triggered level shifters and a differential output stage that generates...... conditions is 0.936 mW including the load. The integrated circuits measured prove to be consistent and robust to local process variations by measurements....

  2. A high voltage gain quasi Z-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A compact quasi-Z-source DC/DC converter is presented with high voltage gain, isolated output, and improved efficiency. The improvements in size and performance were achieved by using a square wave inverter with only two output switches driving an isolating transformer in push-pull mode, followed...... by a voltage doubling output rectifier. The converter is well-suited to applications requiring a high voltage gain, especially renewable energy sources such as photovoltaic and fuel-cell power supplies. To demonstrate the converter's performance a prototype designed to output 400 V at 500 W was constructed...

  3. High-Voltage LED Light Engine with Integrated Driver

    Energy Technology Data Exchange (ETDEWEB)

    Soer, Wouter [Lumileds LLC, San Jose, CA (United States)

    2016-02-29

    LED luminaires have seen dramatic changes in cost breakdown over the past few years. The LED component cost, which until recently was the dominant portion of luminaire cost, has fallen to a level of the same order as the other luminaire components, such as the driver, housing, optics etc. With the current state of the technology, further luminaire performance improvement and cost reduction is realized most effectively by optimization of the whole system, rather than a single component. This project focuses on improving the integration between LEDs and drivers. Lumileds has developed a light engine platform based on low-cost high-power LEDs and driver topologies optimized for integration with these LEDs on a single substrate. The integration of driver and LEDs enables an estimated luminaire cost reduction of about 25% for targeted applications, mostly due to significant reductions in driver and housing cost. The high-power LEDs are based on Lumileds’ patterned sapphire substrate flip-chip (PSS-FC) technology, affording reduced die fabrication and packaging cost compared to existing technology. Two general versions of PSS-FC die were developed in order to create the desired voltage and flux increments for driver integration: (i) small single-junction die (0.5 mm2), optimal for distributed lighting applications, and (ii) larger multi-junction die (2 mm2 and 4 mm2) for high-power directional applications. Two driver topologies were developed: a tapped linear driver topology and a single-stage switch-mode topology, taking advantage of the flexible voltage configurations of the new PSS-FC die and the simplification opportunities enabled by integration of LEDs and driver on the same board. A prototype light engine was developed for an outdoor “core module” application based on the multi-junction PSS-FC die and the single-stage switch-mode driver. The light engine meets the project efficacy target of 128 lm/W at a luminous flux

  4. BANSHEE: High-voltage repetitively pulsed electron-beam driver

    International Nuclear Information System (INIS)

    VanHaaften, F.

    1992-01-01

    BANSHEE (Beam Accelerator for a New Source of High-Energy Electrons) this is a high-voltage modulator is used to produce a high-current relativistic electron beam for high-power microwave tube development. The goal of the BANSHEE research is first to achieve a voltage pulse of 700--750 kV with a 1-μs pulse width driving a load of ∼100 Ω, the pulse repetition frequency (PRF) of a few hertz. The ensuing goal is to increase the pulse amplitude to a level approaching 1 MV. We conducted tests using half the modulator with an output load of 200 Ω, up to a level of ∼650 kV at a PRF of 1 Hz and 525 kV at a PRF of 5 Hz. We then conducted additional testing using the complete system driving a load of ∼100 Ω

  5. High-voltage nanosecond Marx generator with quasi-rectangular pulses

    International Nuclear Information System (INIS)

    Bulan, V.V.; Grabovskij, E.V.; Gribov, A.N.; Luzhnov, V.G.

    1999-01-01

    The automated high-voltage nanosecond generator, forming single pulses of any polarity on the load of 17 Ohm with polarity voltage from 100 up to 300 kV at the semiheight of 80 ns and the front of 7 ns is described. The generator is assembled on the basis of low-inductive capacitors, which by discharge form the pulse, close by form to rectangular one [ru

  6. Switching phenomena in high-voltage circuit breakers

    International Nuclear Information System (INIS)

    Nakanishi, K.

    1991-01-01

    The topics covered in this book include: general problems concerning current interruption, the physical arc model, and miscellaneous types of modern switching apparatus, such as gas circuit breakers, gas-insulated switch-gear, vacuum circuit breakers and high-voltage direct-current circuit breakers

  7. High-Current-Density Thermionic Cathodes and the Generation of High-Voltage Electron Beams

    Science.gov (United States)

    1989-04-30

    Cathode Temperature =1700 OC Figure 37: Peak gun voltage = 90 kV -57- 60- 0 EGUN 327 ~40 0S 20’ Vacuum 5 .2 x 10 Tor 0 o 0 15202 30 Time (jis...by modeling the filament as a thin disk. The shape of the H - V -, 2 actual filament is sketched in Fig. 2. The EGUN code 1 131 is used to calculate

  8. Design of High Voltage Electrical Breakdown Strength measuring system at 1.8K with a G-M cryocooler

    Science.gov (United States)

    Li, Jian; Huang, Rongjin; Li, Xu; Xu, Dong; Liu, Huiming; Li, Laifeng

    2017-09-01

    Impregnating resins as electrical insulation materials for use in ITER magnets and feeder system are required to be radiation stable, good mechanical performance and high voltage electrical breakdown strength. In present ITER project, the breakdown strength need over 30 kV/mm, for future DEMO reactor, it will be greater than this value. In order to develop good property insulation materials to satisfy the requirements of future fusion reactor, high voltage breakdown strength measurement system at low temperature is necessary. In this paper, we will introduce our work on the design of this system. This measuring system has two parts: one is an electrical supply system which provides the high voltage from a high voltage power between two electrodes; the other is a cooling system which consists of a G-M cryocooler, a superfluid chamber and a heat switch. The two stage G-M cryocooler pre-cool down the system to 4K, the superfluid helium pot is used for a container to depress the helium to superfluid helium which cool down the sample to 1.8K and a mechanical heat switch connect or disconnect the cryocooler and the pot. In order to provide the sufficient time for the test, the cooling system is designed to keep the sample at 1.8K for 300 seconds.

  9. High voltage high brightness electron accelerator with MITL voltage adder coupled to foilless diode

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Poulkey, J.W.; Rovang, D.

    1995-01-01

    The design and analysis of a high brightness electron beam experiment under construction at Sandia National Laboratory is presented. The beam energy is 12 MeV, the current 35-40 kA, the rms radius 0.5 mm, and the pulse duration FWHM 40 ns. The accelerator is SABRE a pulsed inductive voltage adder, and the electron source is a magnetically immersed foilless diode. This experiment has as its goal to stretch the technology to the edge and produce the highest possible electron current in a submillimeter radius beam

  10. Development of method for detecting signs deterioration in insulator of high-voltage motors. 2. Test Results of a new on-line partial discharge monitor for high-voltage motors in nuclear power stations

    International Nuclear Information System (INIS)

    Tochio, Atsushi; Kaneda, Yoshiharu; Urakawa, Nobuo

    2000-01-01

    For the purpose of early detection of deterioration of insulators in high-voltage motors which are widely utilized in nuclear power stations, a new on-line partial discharge (PD) monitor was developed and was tested for sixteen motors which were practically running in nuclear power stations. From the test results, it is seen that (1) good signal to noise ratio is obtained by adopting a two frequency correlation method, (2) a resistance temperature detector (RTD) in a motor has sufficient sensitivity to detect PD, (3) when RTD is not installed or is unable to use for this purpose, a radio frequency current transformer (RFCT) can be utilized, although its sensitivity is about 1/10 of that of the RTD monitor. Finally we found a good correlation between the results of this on-line method and the conventional off-line method in which the insulator resistance of a concerned motor was measured during its shut-down, and thereby we demonstrated that this method could be applicable to the on-line test of high-voltage motors in nuclear power stations. (author)

  11. Atypical Exit Wound in High-Voltage Electrocution.

    Science.gov (United States)

    Parakkattil, Jamshid; Kandasamy, Shanmugam; Das, Siddhartha; Devnath, Gerard Pradeep; Chaudhari, Vinod Ashok; Shaha, Kusa Kumar

    2017-12-01

    Electrocution fatality cases are difficult to investigate. High-voltage electrocution burns resemble burns caused by other sources, especially if the person survives for few days. In that case, circumstantial evidence if correlated with the autopsy findings helps in determining the cause and manner of death. In addition, the crime scene findings also help to explain the pattern of injuries observed at autopsy. A farmer came in contact with a high-voltage transmission wire and sustained superficial to deep burns over his body. A charred and deeply scorched area was seen over the face, which was suggestive of the electric entry wound. The exit wound was present over both feet and lower leg and was atypical in the form of a burnt area of peeled blistered skin, charring, and deep scorching. The injuries were correlated with crime scene findings, and the circumstances that lead to his electrocution are discussed here.

  12. High voltage isolation transformer

    Science.gov (United States)

    Clatterbuck, C. H.; Ruitberg, A. P. (Inventor)

    1985-01-01

    A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

  13. The Investigation of Field Plate Design in 500 V High Voltage NLDMOS

    Directory of Open Access Journals (Sweden)

    Donghua Liu

    2015-01-01

    Full Text Available This paper presents a 500 V high voltage NLDMOS with breakdown voltage (VBD improved by field plate technology. Effect of metal field plate (MFP and polysilicon field plate (PFP on breakdown voltage improvement of high voltage NLDMOS is studied. The coeffect of MFP and PFP on drain side has also been investigated. A 500 V NLDMOS is demonstrated with a 37 μm drift length and optimized MFP and PFP design. Finally the breakdown voltage 590 V and excellent on-resistance performance (Rsp = 7.88 ohm * mm2 are achieved.

  14. Prototype high voltage bushing: Configuration to its operational demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Sejal, E-mail: sshah@iter-india.org [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Sharma, D. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Parmar, D.; Tyagi, H.; Joshi, K.; Shishangiya, H.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2016-12-15

    High Voltage Bushing (HVB) is the key component of Diagnostic Neutral Beam (DNB) system of ITER as it provides access to high voltage electrical, hydraulic, gas and diagnostic feedlines to the beam source with isolation from grounded vessel. HVB also provides primary vacuum confinement for the DNB system. Being Safety Important Class (SIC) component of ITER, it involves several configurational, technological and operational challenges. To ensure its operational performance & reliability, particularly electrostatic behavior, half scale down Prototype High Voltage Bushing (PHVB) is designed considering same design criteria of DNB HVB. Design optimization has been carried out followed by finite element (FE) analysis to obtain DNB HVB equivalent electric stress on different parts of PHVB, taking into account all design, manufacturing & space constraints. PHVB was tested up to 60 kV without breakdown, which validates its design for the envisaged operation of 50 kV DC. This paper presents the design of PHVB, FEA validation, manufacturing constraints, experimental layout with interfacing auxiliary systems and operational results related to functional performance.

  15. AC transmission, with very high voltages and the 750 kV line

    Energy Technology Data Exchange (ETDEWEB)

    Bocker, H

    1964-01-01

    The economic case for adoption of extra-high voltages for transmitting electric power over distances of the order of 1000 km is discussed. Some special technical developments for solving the problems attached to such high voltages are briefly discussed, particularly in the fields of switching and transients suppression. The first 750-kV projects in Canada and Russia are mentioned. Equipment, e.g., bushings, transformers, etc., operating at such voltages are illustrated.

  16. Use of multi-functional flexible micro-sensors for in situ measurement of temperature, voltage and fuel flow in a proton exchange membrane fuel cell.

    Science.gov (United States)

    Lee, Chi-Yuan; Chan, Pin-Cheng; Lee, Chung-Ju

    2010-01-01

    Temperature, voltage and fuel flow distribution all contribute considerably to fuel cell performance. Conventional methods cannot accurately determine parameter changes inside a fuel cell. This investigation developed flexible and multi-functional micro sensors on a 40 μm-thick stainless steel foil substrate by using micro-electro-mechanical systems (MEMS) and embedded them in a proton exchange membrane fuel cell (PEMFC) to measure the temperature, voltage and flow. Users can monitor and control in situ the temperature, voltage and fuel flow distribution in the cell. Thereby, both fuel cell performance and lifetime can be increased.

  17. High-voltage pulsed generator for dynamic fragmentation of rocks.

    Science.gov (United States)

    Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  18. High-voltage pulsed generator for dynamic fragmentation of rocks

    Science.gov (United States)

    Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  19. The electric strength of high-voltage transformers insulation at effect of partial dischargers

    International Nuclear Information System (INIS)

    Khoshravan, E.; Zeraatparvar, A.; Gashimov, A.M.; Mehdizadeh, R.N.

    2001-01-01

    Full text : In paper the change of electric strength of high-voltage transformers insulation at the effect of partial discharges with space charge accumulation was investigated. It is revealed that the effect of partial discharges of insulation materials results the reduction of their pulsing electric strength which can restore the own initial value at releasing of saved charge the volume of a material under condition of absence the ineversible structural changes in it. Researches of high-voltage transformers insulation's non-failure operation conditions show, that at increasing of insulation work time in a strong electrical field the reduction of average breakdown voltages with simultaneous increasing of spread in discharge voltage values takes place. It authentically testifies to reduction of short-time discharge voltage of insulation materials during their electrical aging. As the basic reason of insulation electrical aging the partial discharges occurring in gas cavities inside insulation were considered. It is known that the space charges will be formed in insulation elements of high-voltage devices which effects in dielectrical property of these elements including the electric strength and the space charge formation can occur also at partial discharges in an alternating voltage while the service of high-voltage transformers. In the given work the experiments in revealing separate influence partial discharges in pulsing electric strength of insulation materials at presence and at absence inside them the space charge were spent

  20. Multi-Port High Voltage Gain Modular Power Converter for Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Sen Song

    2018-06-01

    Full Text Available In high voltage direct current (HVDC power transmission of offshore wind power systems, DC/DC converters are applied to transfer power from wind generators to HVDC terminals, and they play a crucial role in providing a high voltage gain, high efficiency, and high fault tolerance. This paper introduces an innovative multi-port DC/DC converter with multiple modules connected in a scalable matrix configuration, presenting an ultra-high voltage step-up ratio and low voltage/current rating of components simultaneously. Additionally, thanks to the adoption of active clamping current-fed push–pull (CFPP converters as sub-modules (SMs, soft-switching is obtained for all power switches, and the currents of series-connected CFPP converters are auto-balanced, which significantly reduce switching losses and control complexity. Furthermore, owing to the expandable matrix structure, the output voltage and power of a modular converter can be controlled by those of a single SM, or by adjusting the column and row numbers of the matrix. High control flexibility improves fault tolerance. Moreover, due to the flexible control, the proposed converter can transfer power directly from multiple ports to HVDC terminals without bus cable. In this paper, the design of the proposed converter is introduced, and its functions are illustrated by simulation results.

  1. Theoretical investigation of a photoconductively switched high-voltage spark gap

    NARCIS (Netherlands)

    Broks, B.H.P.; Hendriks, J.; Brok, W.J.M.; Brussaard, G.J.H.; Mullen, van der J.J.A.M.

    2006-01-01

    In this contribution, a photoconductively switched high-voltage spark gap with an emphasis on theswitching behavior is modeled. It is known experimentally that not all of the voltage that is present at the input of the spark gap is switched, but rather a fraction of it drops across the spark gap.

  2. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

  3. Summary of transient high-voltage calculations for the FRX-C experiment

    International Nuclear Information System (INIS)

    Kewish, R.W. Jr.; Rej, D.J.

    1982-06-01

    Calculations of the electrical circuit equations are performed over a wide range of parameters corresponding to the FRX-C field-reversed THETA-pinch experiment at Los Alamos. Without any plasma or external damping, serious voltage doubling and quadrupling of the main capacitor bank charge voltage are observed. These oscillating high voltages are found to be adequately suppressed by the strategic placement of external snubber circuitry. On the other hand, no doubling of the THETA-pinch preionization bank charge voltage is found. Calculations of the equations for the z-pinch preionization circuit are also performed

  4. High voltage pulse system for the streamer chamber supply of the GIBS spectrometer

    International Nuclear Information System (INIS)

    Aksinenko, V.D.; Glagoleva, N.S.; Dement'ev, E.A.; Kaminskij, N.I.; Matyushin, A.T.; Matyushin, V.T.; Rozhnyatovskaya, S.A.; Ryakhovskij, V.N.; Nurgozhin, N.N.; Khusainov, E.K.

    1987-01-01

    Results of development and testing of high voltage pulse system HVPS for the streamer chamber supply of the GIBS spectrometer are presented. HVPS consists of the following basic blocks: nanosecond pulse high voltage generator, high voltage charging supply, trigger generator, chamber parameter control devices, gas-oil vacuuming supply systems, auxiliary and fire-prevention devices. The system blocks are described. Experimental results of HVPC testing are presented. HVPC provides a reliable (10 5 operations) of streamer chamber supply with high voltage pulse parameters: amplitude - 500 kV, amplitude instability (0.5-1.5)%, pulse duration - 12 ns, delay time - 500 ns, delay instability (2.5-5)%, mean frequency of output a signals - 0.1 Hz

  5. Design of high voltage power supply of miniature X-ray tube based on resonant Royer

    International Nuclear Information System (INIS)

    Liu Xiyao; Zeng Guoqiang; Tan Chengjun; Luo Qun; Gong Chunhui; Huang Rui

    2013-01-01

    Background: In recent years, X rays are widely used in various fields. With the rapid development of national economy, the demand of high quality, high reliability, and high stability miniature X-ray tube has grown rapidly. As an important core component of miniature X-ray tube, high voltage power supply has attracted wide attention. Purpose: To match miniature, the high voltage power supply should be small, lightweight, good quality, etc. Based on the basic performance requirements of existing micro-X-ray tube high voltage power supply, this paper designs an output from 0 to -30 kV adjustable miniature X-ray tube voltage DC power supply. Compared to half-bridge and full-bridge switching-mode power supply, its driving circuit is simple. With working on the linear condition, it has no switching noise. Methods: The main circuit makes use of DC power supply to provide the energy. The resonant Royer circuit supplies sine wave which drives to the high frequency transformer's primary winding with resultant sine-like high voltage appearing across the secondary winding. Then, the voltage doubling rectifying circuit would achieve further boost. In the regulator circuit, a feedback control resonant transistor base current is adopted. In order to insulate air, a silicone rubber is used for high pressure part packaging, and the output voltage is measured by the dividing voltage below -5 kV. Results: The stability of circuit is better than 0.2%/6 h and the percent of the output ripple voltage is less than 0.3%. Keeping the output voltage constant, the output current can reach 57 μA by changing the size of load resistor. This high voltage power supply based on resonant Royer can meet the requirement of miniature X-ray tube. Conclusions: The circuit can satisfy low noise, low ripple, low power and high voltage regulator power supply design. However, its efficiency is not high enough because of the linear condition. In the next design, to further reduce power consumption, we

  6. Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.

    Science.gov (United States)

    Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

    2013-10-04

    Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry.

  7. Optically triggered high voltage switch network and method for switching a high voltage

    Science.gov (United States)

    El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  8. Optically triggered high voltage switch network and method for switching a high voltage

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  9. Optical fiber imaging for high speed plasma motion diagnostics: Applied to low voltage circuit breakers

    International Nuclear Information System (INIS)

    McBride, J. W.; Balestrero, A.; Tribulato, G.; Ghezzi, L.; Cross, K. J.

    2010-01-01

    An integrated portable measurement system is described for the study of high speed and high temperature unsteady plasma flows such as those found in the vicinity of high current switching arcs. An array of optical fibers allows the formation of low spatial resolution images, with a maximum capture rate of 1x10 6 images per second (1 MHz), with 8 bit intensity resolution. Novel software techniques are reported to allow imaging of the arc; and to measure arc trajectories. Results are presented on high current (2 kA) discharge events in a model test fixture and on the application to a commercial low voltage circuit breaker.

  10. 30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of any...

  11. High Voltage Distribution System (HVDS) as a better system compared to Low Voltage Distribution System (LVDS) applied at Medan city power network

    Science.gov (United States)

    Dinzi, R.; Hamonangan, TS; Fahmi, F.

    2018-02-01

    In the current distribution system, a large-capacity distribution transformer supplies loads to remote locations. The use of 220/380 V network is nowadays less common compared to 20 kV network. This results in losses due to the non-optimal distribution transformer, which neglected the load location, poor consumer profile, and large power losses along the carrier. This paper discusses how high voltage distribution systems (HVDS) can be a better system used in distribution networks than the currently used distribution system (Low Voltage Distribution System, LVDS). The proposed change of the system into the new configuration is done by replacing a large-capacity distribution transformer with some smaller-capacity distribution transformers and installed them in positions that closest to the load. The use of high voltage distribution systems will result in better voltage profiles and fewer power losses. From the non-technical side, the annual savings and payback periods on high voltage distribution systems will also be the advantage.

  12. Sign of inverse spin Hall voltages generated by ferromagnetic resonance and temperature gradients in yttrium iron garnet platinum bilayers

    International Nuclear Information System (INIS)

    Schreier, Michael; Lotze, Johannes; Gross, Rudolf; Goennenwein, Sebastian T B; Bauer, Gerrit E W; Uchida, Ken-ichi; Daimon, Shunsuke; Kikkawa, Takashi; Saitoh, Eiji; Vasyuchka, Vitaliy I; Lauer, Viktor; Chumak, Andrii V; Serga, Alexander A; Hillebrands, Burkard; Flipse, Joost; Van Wees, Bart J

    2015-01-01

    We carried out a concerted effort to determine the absolute sign of the inverse spin Hall effect voltage generated by spin currents injected into a normal metal. We focus on yttrium iron garnet (YIG)∣platinum bilayers at room temperature, generating spin currents by microwaves and temperature gradients. We find consistent results for different samples and measurement setups that agree with theory. We suggest a right-hand-rule to define a positive spin Hall angle corresponding to the voltage expected for the simple case of scattering of free electrons from repulsive Coulomb charges. (paper)

  13. Accelerator System Development at High Voltage Engineering

    International Nuclear Information System (INIS)

    Klein, M. G.; Gottdang, A.; Haitsma, R. G.; Mous, D. J. W.

    2009-01-01

    Throughout the years, HVE has continuously extended the capabilities of its accelerator systems to meet the rising demands from a diverse field of applications, among which are deep level ion implantation, micro-machining, neutron production for biomedical research, isotope production or accelerator mass spectrometry. Characteristic for HVE accelerators is the coaxial construction of the all solid state power supply around the acceleration tubes. With the use of solid state technology, the accelerators feature high stability and very low ripple. Terminal voltages range from 1 to 6 MV for HVE Singletrons and Tandetrons. The high-current versions of these accelerators can provide ion beams with powers of several kW. In the last years, several systems have been built with terminal voltages of 1.25 MV, 2 MV and 5 MV. Recently, the first system based on a 6 MV Tandetron has passed the factory tests. In this paper we describe the characteristics of the HVE accelerator systems and present as example recent systems.

  14. Capacity Decline and Characteristics Changes of Lithium-ion Cells with Large Capacity during Trickle Charge at High Temperature

    Science.gov (United States)

    Matsushima, Toshio

    Large-scale 40-Ah Li-ion cells have been developed for use in industrial applications. To contribute to techniques for ascertaining the state of these cells and detecting deterioration during actual use, we produce a cell whose capacity is reduced by trickle charging at high temperature, and we determine the relationship between the cell's properties such as its capacity and charging/discharging characteristics when the capacity is reduced. When the capacity of a Li-ion cell is reduced, the discharge voltage also decreases. We show that the residual capacity is well correlated to the discharge voltage and to the duration of continuous discharge before reaching a fixed end-voltage. We also show that the constant-current constant-voltage charging characteristics are maintained even when the capacity is degraded, and that the constant-current charging time and discharge voltage are closely related to the residual capacity. We confirm that the reaction coefficient of the capacity degradation formula can be calculated from the capacity change characteristics at multiple temperatures, and that an 8°C change in temperature causes the lifetime to decrease by half.

  15. A Novel Quasi-SEPIC High-Voltage Boost DC-DC Converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; N. Soltani, Mohsen; Blaabjerg, Frede

    2017-01-01

    This paper proposes a modified coupled-inductor SEPIC dc-dc converter for low power and high voltage gain applications such as for piezoelectric drive systems. The converter uses the same components as of SEPIC converter with an additional diode. Compared to conventional topologies with similar...... voltage gain expression, the proposed topology uses less components to achieve same or even higher voltage gain. This helps to design a very compact and light weight converter with higher power density at lower cost. Due to brevity, the principle of operation, theoretical analysis and comparison supported...

  16. On-load Tap Changer Diagnosis on High-Voltage Power Transformers using Dynamic Resistance Measurements

    NARCIS (Netherlands)

    Erbrink, J.J.

    2011-01-01

    High-voltage transformers have tap changers to regulate the voltage in the high-voltage network when the load changes. Those tap changers are subject to different degradation mechanisms and need regular maintenance. Various defects, like contact degradation, often remain undetected and the

  17. High-power high-voltage pulse generator for supplying electrostatic precipitators of dust

    International Nuclear Information System (INIS)

    Radu, A.; Martin, D.

    1992-01-01

    The study and development of an experimental high voltage generator specialized in the supply of electrostatic precipitators are presented. The main parameters of the pulse generator are: U = -30 kV, I = 8.8 A, τ = 120μs, f r = 150 Hz. The pulse generator was tested on a laboratory electrostatic precipitator with nominal capacitance C = 25 nF, biased at -40 kV by means of a separate high voltage rectifier. The experimental results will be used for the creation of a more powerful pulse generator, a prototype for the supply of a real industrial electrostatic precipitator: U = -50 kV, I = 313 A, τ = 100μs, f r = 300 Hz, C = 100 nF. (Author)

  18. Improvement the Capacity of Cockcroft-Walton High Voltage Source from 300 kV/20 mA to 500 kV/20 mA for Accelerating Voltage of Electron Beam Machine

    International Nuclear Information System (INIS)

    Suprapto; Djasiman

    2002-01-01

    The improvement capacity of Cockcroft-Walton high voltage source from 300 kV/20 mA to 500 kV/mA has been carrying out. To improve the capacity of high voltage source was done by means of increasing the stage number of voltage multiplier from 11 to 18 and its output voltage measuring resistance. Each stage of voltage multiplier consists of 2 capacitors and 2 circuits of high voltage diode. This voltage multiplier is constructed using main components of high voltage capacitor and high voltage diode each of 0.22 μF/50 kV and UF 5408 respectively. To avoid stray discharge and corona it was provided with high voltage electrode and corona ring. The test result indicated that the output voltage obtained from 16 stages was 350 kV according to operating condition of 25 MΩ resistive load and first stage voltage of 28.5 kV with oscillator frequency of 24 Hz. That condition requires anode voltage and current of 5.5 kV and 2.5 A respectively. The no load test for 16 stages indicates 400 kV of output voltage and 28.5 kV first stage voltage. Efficiency of high voltage source was 48 % at 6.75 kW of output power. The expected test of 500 kV with 18 stages of voltage multiplier can not be carried out because of some restrictive of loading system. From the test result can be predicted that the output voltage of 500 kV with 18 stages of voltage multiplier requires 31.2 kV of first stage voltage. Then the expected high voltage source of Cockcroft-Walton is capable as accelerating voltage source for Electron Beam Machine with energy of 500 kV. (author)

  19. Ultra Fast, High Rep Rate, High Voltage Spark Gap Pulser

    Science.gov (United States)

    1995-07-01

    current rise time. The spark gap was designed to have a coaxial geometry reducing its inductance. Provisions were made to pass flowing gas between the...ULTRA FAST, HIGH REP RATE, HIGH VOLTAGE SPARK GAP PULSER Robert A. Pastore Jr., Lawrence E. Kingsley, Kevin Fonda, Erik Lenzing Electrophysics and...Modeling Branch AMSRL-PS-EA Tel.: (908)-532-0271 FAX: (908)-542-3348 U.S. Army Research Laboratory Physical Sciences Directorate Ft. Monmouth

  20. A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

    Science.gov (United States)

    Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

    2012-01-01

    This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters.

  1. A Protection System of High Voltage Generator Electron Acceleration foran Electron Beam Machine 500 kV/10 mA

    International Nuclear Information System (INIS)

    Prajitno; Sudiyanto; Djaziman

    2000-01-01

    Hardwired electronic circuit of protection system to prevent high voltagegenerator EBM have been made. The protection system consists of processparameters such as safety parameter, dynamic logic circuits and interlockrelay drive circuits. Safety parameters using transducer which is factorymade so that the accuracy and reliability could be controlled. A good resultof electronic circuit has been tested which cover: water flow and temperaturemonitoring, grid current, anode current, anode voltage and logic control. Therange of monitoring temperature from 30 o C to 100 o C with output voltagefrom 1.47 V to 5.38 V. The voltage output of water flow monitoring is 0.083 Vto 3.391 V which is equivalent to 1.5 - 30 l/min. Response time of the logiccontrol about 10 ms. By using design and construction of protection system,have been through about the security aspect of high voltage generatoroperation and also system will give early warning if the disturbance andabnormal operation occurred. (author)

  2. Multi-cell DC-DC converter with high step-down voltage ratio

    NARCIS (Netherlands)

    Tibola, G.; Duarte, J.L.; Blinov, A.

    2015-01-01

    The use of high voltage allows a power processing system to operate with low currents, improving efficiency. Nevertheless, final applications usually require low voltage inlet, which can be provided using modular multilevel converters submodules, for instance. However, every submodule's gate-unit

  3. A nanosecond high voltage pulse device for accelerator time analytical system

    International Nuclear Information System (INIS)

    Lou Binqiao; Ding Furong; Xue Zhihua; Wang Xuemei; Shen Dingyu

    2002-01-01

    A nanosecond high voltage pulse device has been designed. The pulse rise time is 10 ns. The pulse voltage reached 16000 V. This device has been used to accelerator time analytical system, its resolution time is less than 0.8%

  4. Strongly emissive perovskite nanocrystal inks for high-voltage solar cells

    Science.gov (United States)

    Akkerman, Quinten A.; Gandini, Marina; di Stasio, Francesco; Rastogi, Prachi; Palazon, Francisco; Bertoni, Giovanni; Ball, James M.; Prato, Mirko; Petrozza, Annamaria; Manna, Liberato

    2016-12-01

    Lead halide perovskite semiconductors have recently gained wide interest following their successful embodiment in solid-state photovoltaic devices with impressive power-conversion efficiencies, while offering a relatively simple and low-cost processability. Although the primary optoelectronic properties of these materials have already met the requirement for high-efficiency optoelectronic technologies, industrial scale-up requires more robust processing methods, as well as solvents that are less toxic than the ones that have been commonly used so successfully on the lab-scale. Here we report a fast, room-temperature synthesis of inks based on CsPbBr3 perovskite nanocrystals using short, low-boiling-point ligands and environmentally friendly solvents. Requiring no lengthy post-synthesis treatments, the inks are directly used to fabricate films of high optoelectronic quality, exhibiting photoluminescence quantum yields higher than 30% and an amplified spontaneous emission threshold as low as 1.5 μJ cm-2. Finally, we demonstrate the fabrication of perovskite nanocrystal-based solar cells, with open-circuit voltages as high as 1.5 V.

  5. Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

    Energy Technology Data Exchange (ETDEWEB)

    Maxson, Jared; Bazarov, Ivan; Dunham, Bruce; Dobbins, John; Liu, Xianghong; Smolenski, Karl [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States)

    2014-09-15

    A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. These results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.

  6. The nonideality coefficient of current-voltage characteristics for p-n junctions in a high ultrahigh-frequency (microwave) field

    International Nuclear Information System (INIS)

    Shamirzaev, S. H.; Gulyamov, G.; Dadamirzaev, M. G.; Gulyamov, A. G.

    2009-01-01

    The effect of heating of electrons and holes on the nonideality coefficient of the current-voltage characteristic for a p-n junction in a high microwave field is studied. It is established that the nonideality coefficient for a diode depends on the type of charge carriers that make the major contribution to the current in the p-n junction. It is shown that, in some cases in silicon samples, the nonideality coefficient for the diode is governed by the temperature for holes in spite of the fact that the temperature for electrons is higher than the temperature for holes.

  7. The high voltage divider - a tool for comparison of measurement equipment in diagnostic radiology

    International Nuclear Information System (INIS)

    Slavchev, A.; Litchev, A.; Constantinov, B.

    2004-01-01

    The high voltage divider (HVD) is designed for control and analysis of the characteristics of the X-ray generator. The low voltage analogous signals produced by the divider are proportional to the high voltage (kVp) applied to the x-ray tube by a ratio 1:1000 or 1:10000 and can be measured with external test devices like storage oscilloscope (or digital multimeter). The exposure duration and the wave form may be visualized, too. Apart of this invasive way the high voltage also may be measured non-invasively by means of appropriate devices as well as indirectly through calculations. Since the invasive method of measurement with the high voltage divider is distinguished by a high accuracy, it may be utilized as an effective tool for calibration of different devices and for comparison of the measurement methods. (authors)

  8. Alpha-ray spectrometry at high temperature by using a compound semiconductor detector.

    Science.gov (United States)

    Ha, Jang Ho; Kim, Han Soo

    2013-11-01

    The use of conventional radiation detectors in harsh environments is limited by radiation damage to detector materials and by temperature constraints. We fabricated a wide-band gap semiconductor radiation detector based on silicon carbide. All the detector components were considered for an application in a high temperature environment like a nuclear reactor core. The radiation response, especially to alpha particles, was measured using an (241)Am source at variable operating voltages at room temperature in the air. The temperature on detector was controlled from 30°C to 250°C. The alpha-particle spectra were measured at zero bias operation. Even though the detector is operated at high temperature, the energy resolution as a function of temperature is almost constant within 3.5% deviation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. 30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage power lines. 56.12071 Section 56.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley...

  10. Serially Connected Micro Amorphous Silicon Solar Cells for Compact High-Voltage Sources

    Directory of Open Access Journals (Sweden)

    Jiyoon Nam

    2016-01-01

    Full Text Available We demonstrate a compact amorphous silicon (a-Si solar module to be used as high-voltage power supply. In comparison with the organic solar module, the main advantages of the a-Si solar module are its compatibility with photolithography techniques and relatively high power conversion efficiency. The open circuit voltage of a-Si solar cells can be easily controlled by serially interconnecting a-Si solar cells. Moreover, the a-Si solar module can be easily patterned by photolithography in any desired shapes with high areal densities. Using the photolithographic technique, we fabricate a compact a-Si solar module with noticeable photovoltaic characteristics as compared with the reported values for high-voltage power supplies.

  11. On some aspects of high voltage electron microscopy

    International Nuclear Information System (INIS)

    Jouffrey, B.; Trinquier, J.

    1987-01-01

    The present paper deals with high voltage electron microscopy (HVEM). It is an overview on this domain due to the pionneer work of G. Dupouy which has permitted to perform a new kind of electron microscopy. Since this time, HVEM has shown its interest in high resolution, irradiations, chemical analysis, in situ experiments

  12. A new VME-based high voltage power supply for large photomultiplier systems

    International Nuclear Information System (INIS)

    Neumaier, S.; Hubbeling, T.; Kolb, B.W.; Purschke, M.L.; Ippolitov, M.; Blume, C.; Bohne, E.M.; Bucher, D.; Claussen, A.; Peitzmann, T.; Schepers, G.; Schlagheck, H.

    1995-01-01

    We describe a new high voltage power supply, developed for the leadglass calorimeter of the WA98 experiment at CERN. The high voltage is produced for each of the 10,080 photomultiplier tubes of the detector individually, by the same number of active bases with on-board Greinacher voltage multipliers. The full VME-based HV controller system, which addresses each base via bus cables once per second, is miniaturized and fits into a single VME crate. The main advantages of this approach are the low heat dissipation, the considerably reduced amount of cabling and cost, as well as the high stability and low noise of the system. (orig.)

  13. The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

    Science.gov (United States)

    Gao, Xuetong; Liu, Zhian; Zhao, Judong

    2018-01-01

    Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

  14. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any...

  15. SSP Technology Investigation of a High-Voltage DC-DC Converter

    Science.gov (United States)

    Pappas, J. A.; Grady, W. M.; George, Patrick J. (Technical Monitor)

    2002-01-01

    The goal of this project was to establish the feasibility of a high-voltage DC-DC converter based on a rod-array triggered vacuum switch (RATVS) for the Space Solar Power system. The RATVS has many advantages over silicon and silicon-carbide devices. The RATVS is attractive for this application because it is a high-voltage device that has already been demonstrated at currents in excess of the requirement for an SSP device and at much higher per-device voltages than existing or near-term solid state switching devices. The RATVS packs a much higher specific power rating than any solid-state device and it is likely to be more tolerant of its surroundings in space. In addition, pursuit of an RATVS-based system would provide NASA with a nearer-term and less expensive power converter option for the SSP.

  16. PIEZOELECTRIC WAVEGUIDE SENSOR FOR MEASURING PULSE PRESSURE IN CLOSED LIQUID VOLUMES AT HIGH VOLTAGE ELECTRIC DISCHARGE

    Directory of Open Access Journals (Sweden)

    V. G. Zhekul

    2017-10-01

    Full Text Available Purpose. Investigations of the characteristics of pressure waves presuppose the registration of the total profile of the pressure wave at a given point in space. For these purposes, various types of «pressure to the electrical signal» transmitters (sensors are used. Most of the common sensors are unsuitable for measuring the pulse pressure in a closed water volume at high hydrostatic pressures, in particular to study the effect of a powerful high-voltage pulse discharge on increasing the inflow of minerals and drinking water in wells. The purpose of the work was to develop antijamming piezoelectric waveguide sensor for measuring pulse pressure at a close distance from a high-voltage discharge channel in a closed volume of a liquid. Methodology. We have applied the calibration method as used as a secondary standard, the theory of electrical circuits. Results. We have selected the design and the circuit solution of the waveguide pressure sensor. We have developed a waveguide pulse-pressure sensor DTX-1 with a measuring loop. This sensor makes it possible to study the spectral characteristics of pressure waves of high-voltage pulse discharge in closed volumes of liquid at a hydrostatic pressure of up to 20 MPa and a temperature of up to 80 °C. The sensor can be used to study pressure waves with a maximum amplitude value of up to 150 MPa and duration of up to 80 µs. According to the results of the calibration, the sensitivity of the developed sensor DTX-1 with a measuring loop is 0.0346 V/MPa. Originality. We have further developed the theory of designing the waveguide piezoelectric pulse pressure sensors for measuring the pulse pressure at a close distance from a high-voltage discharge channel in a closed fluid volume by controlling the attenuation of the amplitude of the pressure signal. Practical value. We have developed, created, calibrated, used in scientific research waveguide pressure pulse sensors DTX-1. We propose sensors DTX-1 for sale

  17. Cermet insert high voltage holdoff improvement for ceramic/metal vacuum devices

    Science.gov (United States)

    Ierna, W.F.

    1986-03-11

    An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

  18. Design of a termination for a high temperature superconduction power cable

    DEFF Research Database (Denmark)

    Rasmussen, Carsten; Kühle (fratrådt), Anders Van Der Aa; Tønnesen, Ole

    1999-01-01

    ). This assembly is electrically insulated with an extruded polymer dielectric kept at room temperature. Cooling is provided by a flow of liquid nitrogen inside the former. The purpose of the termination is to connect the superconducting cable conductor at cryogenic temperature to the existing power grid at room...... temperatures, the transfer of liquid nitrogen over a high voltage drop and that of providing a well defined atmosphere inside the termination and around the cable conductor. Designs based on calculations and experiments will be presented. The solutions are optimized with respect to a low heat in-leak....

  19. Integrated Three-Voltage-Booster DC-DC Converter to Achieve High Voltage Gain with Leakage-Energy Recycling for PV or Fuel-Cell Power Systems

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2015-09-01

    Full Text Available In this paper, an integrated three-voltage-booster DC-DC (direct current to direct current converter is proposed to achieve high voltage gain for renewable-energy generation systems. The proposed converter integrates three voltage-boosters into one power stage, which is composed of an active switch, a coupled-inductor, five diodes, and five capacitors. As compared with conventional high step-up converters, it has a lower component count. In addition, the features of leakage-energy recycling and switching loss reduction can be accomplished for conversion efficiency improvement. While the active switch is turned off, the converter can inherently clamp the voltage across power switch and suppress voltage spikes. Moreover, the reverse-recovery currents of all diodes can be alleviated by leakage inductance. A 200 W prototype operating at 100 kHz switching frequency with 36 V input and 400 V output is implemented to verify the theoretical analysis and to demonstrate the feasibility of the proposed high step-up DC-DC converter.

  20. High Voltage Coil Current Sensor for DC-DC Converters Employing DDCC

    Directory of Open Access Journals (Sweden)

    M. Drinovsky

    2015-12-01

    Full Text Available Current sensor is an integral part of every switching converter. It is used for over-current protection, regulation and in case of multiphase converters for balancing. A new high voltage current sensor for coil-based current sensing in DC-DC converters is presented. The sensor employs DDCC with high voltage input stage and gain trimming. The circuit has been simulated and implemented in 0.35 um BCD technology as part of a multiphase DC-DC converter where its function has been verified. The circuit is able to sustain common mode voltage on the input up to 40 V, it occupies 0.387*0.345 mm2 and consumes 3.2 mW typically.

  1. High Voltage Surface Degradation on Carbon Blacks in Lithium Ion Batteries

    DEFF Research Database (Denmark)

    Younesi, Reza

    In order to increase the power density of Li-ion batteries, much research is focused on developing cathode materials that can operate at high voltages above 4.5 V with a high capacity, high cycling stability, and rate capability. However, at high voltages all the components of positive electrodes...... including carbon black (CB) additives have a potential risk of degradation. Though the weight percentage of CB in commercial batteries is generally very small, the volumetric amount and thus the surface area of CB compose a rather large part of a cathode due to its small particle size (≈ 50 nm) and high...

  2. A Novel Series Connected Batteries State of High Voltage Safety Monitor System for Electric Vehicle Application

    Directory of Open Access Journals (Sweden)

    Qiang Jiaxi

    2013-01-01

    Full Text Available Batteries, as the main or assistant power source of EV (Electric Vehicle, are usually connected in series with high voltage to improve the drivability and energy efficiency. Today, more and more batteries are connected in series with high voltage, if there is any fault in high voltage system (HVS, the consequence is serious and dangerous. Therefore, it is necessary to monitor the electric parameters of HVS to ensure the high voltage safety and protect personal safety. In this study, a high voltage safety monitor system is developed to solve this critical issue. Four key electric parameters including precharge, contact resistance, insulation resistance, and remaining capacity are monitored and analyzed based on the equivalent models presented in this study. The high voltage safety controller which integrates the equivalent models and control strategy is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated, and the online electric parameters monitor strategy is analyzed and discussed. The test results indicate that the high voltage safety monitor system designed in this paper is suitable for EV application.

  3. A novel series connected batteries state of high voltage safety monitor system for electric vehicle application.

    Science.gov (United States)

    Jiaxi, Qiang; Lin, Yang; Jianhui, He; Qisheng, Zhou

    2013-01-01

    Batteries, as the main or assistant power source of EV (Electric Vehicle), are usually connected in series with high voltage to improve the drivability and energy efficiency. Today, more and more batteries are connected in series with high voltage, if there is any fault in high voltage system (HVS), the consequence is serious and dangerous. Therefore, it is necessary to monitor the electric parameters of HVS to ensure the high voltage safety and protect personal safety. In this study, a high voltage safety monitor system is developed to solve this critical issue. Four key electric parameters including precharge, contact resistance, insulation resistance, and remaining capacity are monitored and analyzed based on the equivalent models presented in this study. The high voltage safety controller which integrates the equivalent models and control strategy is developed. By the help of hardware-in-loop system, the equivalent models integrated in the high voltage safety controller are validated, and the online electric parameters monitor strategy is analyzed and discussed. The test results indicate that the high voltage safety monitor system designed in this paper is suitable for EV application.

  4. Optimum DMOS cell doping profiles for high-voltage discrete and integrated device technologies

    Science.gov (United States)

    Shenai, Krishna

    1992-05-01

    It is shown that the implantation and activation sequences of B and As result in significant variations in the contact resistance and p-base sheet resistance beneath the n+-source diffusion of a DMOSFET cell. For identical process parameters, the contact resistance of As-doped n+ silicon was significantly improved when high-dose B was implanted due to higher As surface concentration. The SUPREM III process modeling results were found to be in qualitative agreement with the measured spreading resistance profiles and the discrepancies could be attributed to larger high-temperature diffusion constants used in SUPREM III and the coupled As-B diffusion/activation effects that are not accounted for in process modeling. The experimental results are discussed within the framework of fabricating high-performance DMOSFET cells and CMOS high-voltage devices on the same chip for discrete and smart-power applications.

  5. A new high-voltage level-shifting circuit for half-bridge power ICs

    International Nuclear Information System (INIS)

    Kong Moufu; Chen Xingbi

    2013-01-01

    In order to reduce the chip area and improve the reliability of HVICs, a new high-voltage level-shifting circuit with an integrated low-voltage power supply, two PMOS active resistors and a current mirror is proposed. The integrated low-voltage power supply not only provides energy for the level-shifting circuit and the logic circuit, but also provides voltage signals for the gates and sources of the PMOS active resistors to ensure that they are normally-on. The normally-on PMOS transistors do not, therefore, need to be fabricated in the depletion process. The current mirror ensures that the level-shifting circuit has a constant current, which can reduce the process error of the high-voltage devices of the circuit. Moreover, an improved RS trigger is also proposed to improve the reliability of the circuit. The proposed level-shifting circuit is analyzed and confirmed by simulation with MEDICI, and the simulation results show that the function is achieved well. (semiconductor integrated circuits)

  6. Series asymmetric supercapacitors based on free-standing inner-connection electrodes for high energy density and high output voltage

    Science.gov (United States)

    Tao, Jiayou; Liu, Nishuang; Rao, Jiangyu; Ding, Longwei; Al Bahrani, Majid Raissan; Li, Luying; Su, Jun; Gao, Yihua

    2014-11-01

    Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high output voltage.Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high

  7. An optical fiber Bragg grating and piezoelectric ceramic voltage sensor

    Science.gov (United States)

    Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

    2017-10-01

    Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

  8. An optical fiber Bragg grating and piezoelectric ceramic voltage sensor.

    Science.gov (United States)

    Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

    2017-10-01

    Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

  9. 30 CFR 77.803 - Fail safe ground check circuits on high-voltage resistance grounded systems.

    Science.gov (United States)

    2010-07-01

    ... circuits on high-voltage resistance grounded systems. On and after September 30, 1971, all high-voltage... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fail safe ground check circuits on high-voltage resistance grounded systems. 77.803 Section 77.803 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...

  10. Poisson simulation for high voltage terminal of test stand for 1MV electrostatic accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sae-Hoon; Kim, Jeong-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Yu-Seok [Dongguk Univ.., Gyeongju (Korea, Republic of)

    2014-10-15

    KOMAC provide ion beam to user which energy range need to expand to MeV range and develop 1 MV electrostatic accelerator. The specifications of the electrostatic accelerator are 1MV acceleration voltage, 10 mA peak current and variable gas ion. We are developing test stand before set up 1 MV electrostatic accelerator. The test stand voltage is 300 kV and operating time is 8 hours. The test stand is consist of 300 kV high voltage terminal, DC-AC-DC inverter, power supply device inside terminal, 200MHz RF power, 5 kV extraction power supply, 300 kV accelerating tube and vacuum system.. The beam measurement system and beam dump will be installed next to accelerating tube. Poisson code simulation results of the high voltage terminal are presented in this paper. Poisson code has been used to calculate the electric field for high voltage terminal. The results of simulation were verified with reasonable results. The poisson code structure could be apply to the high voltage terminal of the test stand.

  11. Poisson simulation for high voltage terminal of test stand for 1MV electrostatic accelerator

    International Nuclear Information System (INIS)

    Park, Sae-Hoon; Kim, Jeong-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub; Kim, Yu-Seok

    2014-01-01

    KOMAC provide ion beam to user which energy range need to expand to MeV range and develop 1 MV electrostatic accelerator. The specifications of the electrostatic accelerator are 1MV acceleration voltage, 10 mA peak current and variable gas ion. We are developing test stand before set up 1 MV electrostatic accelerator. The test stand voltage is 300 kV and operating time is 8 hours. The test stand is consist of 300 kV high voltage terminal, DC-AC-DC inverter, power supply device inside terminal, 200MHz RF power, 5 kV extraction power supply, 300 kV accelerating tube and vacuum system.. The beam measurement system and beam dump will be installed next to accelerating tube. Poisson code simulation results of the high voltage terminal are presented in this paper. Poisson code has been used to calculate the electric field for high voltage terminal. The results of simulation were verified with reasonable results. The poisson code structure could be apply to the high voltage terminal of the test stand

  12. Mass impregnation plant speeds high voltage cable production

    Energy Technology Data Exchange (ETDEWEB)

    1965-05-07

    A mass impregnation and continuous sheath extrusion plant that will eliminate the long period of vacuum treatment usually required for high voltage oil-filled cables is among the latest techniques included in the new factory at Pirelli General's Eastleigh works. The new factory is said to be the first in Europe designed solely for the manufacture of the full range of oil-filled cables. Possible future increases of system voltages to about 750-kV ac or 1000-kV dc have been taken into account in the design of the works, so that only a small amount of modification and new plant will be involved.

  13. Uv laser triggering of high-voltage gas switches

    International Nuclear Information System (INIS)

    Woodworth, J.R.; Frost, C.A.; Green, T.A.

    1982-01-01

    Two different techniques are discussed for uv laser triggering of high-voltage gas switches using a KrF laser (248 nm) to create an ionized channel through the dielectric gas in a spark gap. One technique uses an uv laser to induce breakdown in SF 6 . For this technique, we present data that demonstrate a 1-sigma jitter of +- 150 ps for a 0.5-MV switch at 80% of its self-breakdown voltage using a low-divergence KrF laser. The other scheme uses additives to the normal dielectric gas, such as tripropylamine, which are selected to undergo resonant two-step ionization in the uv laser field

  14. Characterization and Aging Test Methodology for Power Electronic Devices at High Temperature

    International Nuclear Information System (INIS)

    Ibrahim, A.; Khatir, Z.; Dupont, L.

    2011-01-01

    Power electronic modules are key elements in the chain of power conversion. The application areas include aerospace, aviation, railway, electrical distribution, automotive, home automation, oil industry ... But the use of power electronics in high temperature environments is a major strategic issue in the coming years especially in transport. However, the active components based on silicon are limited in their applications and not suitable for those require both high voltages and high ambient temperatures. The materials with wide energy gap like SiC, GaN and diamond, have the advantage of being able to exceed these limits [1,2]. These materials seem adequate to extremely harsh temperature environments and allow the reduction of cooling systems, but also the increasing of switching frequency. (author)

  15. Increasing break-down strength of the support colomn of high-voltage accelerators

    International Nuclear Information System (INIS)

    Rezvykh, K.A.; Romanov, V.A.

    1981-01-01

    Calculation results of strength of electric field of the EG-2.5 electrostatic accelerator for the support colomn with electrodes of circular and elliptical transverse cross sections are presented. Conducted is the choice of constructing the column under the condition that the dimensions of the tank, high-voltage electrode, step between the sections and internal diameter of the colomn electrodes are not changed. The potential at the high-voltage electrode equals 2.5 MV while the average longitudinal gradient of the colomn field equals 1.25 MV/m. The support insulation colomn of the high-voltage accelerator screened by rings with transverse cross section in the form of orientation oval in some accelerators promotes obtaining higher operating voltage and at the same time increase of operation reliability at the rest unchanged dimensions of the plant because the probability of break-down between the support colomn and the tank wall decreases. The latter is especially significant for most high-energy accelerators as well as for accelerators used in national economy [ru

  16. Apparatus with a cooled X-ray source and a high voltage generator

    Energy Technology Data Exchange (ETDEWEB)

    1977-02-01

    Apparatus, especially for a dental application, with an X-ray source and a high voltage generator, whereby the X-ray source and a high voltage generator are contained in a housing, which is filled with a coolant medium, characterised by the housing being divided into two chambers, whereby the X-ray source is in the first chamber and the high voltage generator is in the second chamber and between the chambers a dividing wall is placed for the screening of the X-ray irradiation from the first chamber from the second, whereby at least one of the walls of the second chamber is elastic to accommodate the expansion of the coolant medium.

  17. Temperature dependence of the radiation induced change of depletion voltage in silicon PIN detectors

    International Nuclear Information System (INIS)

    Ziock, H.J.; Holzscheiter, K.; Morgan, A.; Palounek, A.P.T.; Ellison, J.; Heinson, A.P.; Mason, M.; Wimpenny, S.J.; Barberis, E.; Cartiglia, N.; Grillo, A.; O'Shaughnessy, K.; Rahn, J.; Rinaldi, P.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Webster, A.; Wichmann, R.; Wilder, M.; Coupal, D.; Pal, T.

    1993-01-01

    The silicon microstrip detectors that will be used in the SDC experiment at the Superconducting Super Collider (SSC) will be exposed to very large fluences of charged particles, neutrons, and gammas. The authors present a study of how temperature affects the change in the depletion voltage of silicon PIN detectors damaged by radiation. They study the initial radiation damage and the short-term and long-term annealing of that damage as a function of temperature in the range from -10 degrees C to +50 degrees C, and as a function of 800 MeV proton fluence up to 1.5 x 10 14 p/cm 2 . They express the pronounced temperature dependencies in a simple model in terms of two annealing time constants which depend exponentially on the temperature

  18. High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

    CERN Document Server

    Marzocchi, Badder

    2017-01-01

    The CMS Electromagnetic Calorimeter is made of scintillating lead tungstate crystals, using avalanche photodiodes (APD) as photo-detectors in the barrel part. The high voltage system, consisting of 1224 channels, biases groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3pct/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  19. High voltage traction power supply; Ein- und Mehrspannungssysteme in der Bahnenergieversorgung mit hohen Spannungen

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Ludwig O. [Transnet freight rail, (Technology Management), Braamfontein (South Africa); Lehmann, Michael [Technische Univ. Dresden (Germany). Professur Elektrische Bahnen

    2009-04-15

    Raising the nominal voltage of electric railway systems implies many advantages, therefore several concepts can be presented and compared. Detailed studies on two systems with high contact line voltages were performed for the upgrade of the 1 AC 50 kV railway line in South Africa. Finally requirements for high voltage locomotives are derived and illustrated by examples. (orig.)

  20. Design considerations and data for gas-insulated high voltage structures

    International Nuclear Information System (INIS)

    Hopkins, D.B.

    1975-11-01

    This paper is intended to benefit the person faced with the occasional task of designing gas insulated high-voltage structures or spark gaps and who must decide upon the proper geometry, spacings, gas type, and pressure for reliable voltage-holding. An approach is presented along with a summary of how various factors affect voltage breakdown. The design procedures described apply to situations where the influence of nearby insulators is negligible. The accuracy of the data is estimated to be within 10 to 15 percent, a value usually attained in practice only when one follows the cautionary advice discussed in the paragraphs on materials preparation, gas properties, and conditioning

  1. Multiplex Outputs ns Grade High-voltage Fast Pulse Generator Study

    International Nuclear Information System (INIS)

    Wang Xin; Chen Kenan

    2009-01-01

    Using a double-grid hydrogen thyratron, a fast pulse generator with four outputs, high-voltage, low jitter, was made to use at special occasion.In this paper, the basic structure of pulser, switching theory and double-grid driving of hydrogen thyratron was introduced, and also, the effects of grids driving pulses characteristics, the delay between too grids driving, the reservoir heater voltage and cathode heater voltage on the output are carefully examined in experiments. The pulse generator with four outputs was made to producing pulses with amplitude up to 4 kV, rise-time less than 15 ns and jitter less than 3 ns. (authors)

  2. Improvement in the Design of Metal-Ceramic High Voltage Feedthroughs for use in High Energy Particle Accelerators

    CERN Document Server

    Weterings, W

    1999-01-01

    Large high-voltage devices operate in particle accelerators to steer charged particles in the desired direction. Solid and hollow rods of sintered alumina are used as insulating supports and high-voltage feedthroughs to power the electrodes of these electrostatic systems. The performance of the systems is often limited by voltage breakdown along the surface of the ceramic insulator (so-called surface flashover) or discharge between feedthrough and vacuum tank, which can lead to significant disruptions in terms of overall machine efficiency. Available results on the influence of the mechanical preparation, thermal history and particular cleaning techniques on commercially obtainable alumina samples have been studied in order to investigate possibilities for better preparation methodology of the insulating supports. Also the influence of the relative position of the feedthrough inside the vacuum tank on the high-voltage breakdown behaviour has been studied. This paper describes the theoretical and practical bac...

  3. Effect of combined platinum and electron on the temperature dependence of forward voltage in fast recovery diode

    International Nuclear Information System (INIS)

    Jia Yun-Peng; Zhao Bao; Wu Yu; Zhou Xuan; Li Zhe; Tan Jian; Yang Fei

    2015-01-01

    The temperature dependences of forward voltage drop (V F ) of the fast recovery diodes (FRDs) are remarkably influenced by different lifetime controlled treatments. In this paper the results of an experimental study are presented, which are the lifetime controls of platinum treatment, electron irradiation treatment, and the combined treatment of the above ones. Based on deep level transient spectroscopy (DLTS) measurements, a new level E6 (E C -0.376 eV) is found in the combined lifetime treated (CLT) sample, which is different from the levels of the individual platinum and electron irradiation ones. Comparing the tested V F results of CLT samples with the others, the level E6 is responsible for the degradation of temperature dependence of the forward voltage drop in the FRD. (paper)

  4. Verification of high voltage rf capacitive sheath models with particle-in-cell simulations

    Science.gov (United States)

    Wang, Ying; Lieberman, Michael; Verboncoeur, John

    2009-10-01

    Collisionless and collisional high voltage rf capacitive sheath models were developed in the late 1980's [1]. Given the external parameters of a single-frequency capacitively coupled discharge, plasma parameters including sheath width, electron and ion temperature, plasma density, power, and ion bombarding energy can be estimated. One-dimensional electrostatic PIC codes XPDP1 [2] and OOPD1 [3] are used to investigate plasma behaviors within rf sheaths and bulk plasma. Electron-neutral collisions only are considered for collisionless sheaths, while ion-neutral collisions are taken into account for collisional sheaths. The collisionless sheath model is verified very well by PIC simulations for the rf current-driven and voltage-driven cases. Results will be reported for collisional sheaths also. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16 (1988) 638; 17 (1989) 338 [2] J. P. Verboncoeur, M. V. Alves, V. Vahedi, and C. K. Birdsall, J. Comp. Phys. 104 (1993) 321 [3] J. P. Verboncoeur, A. B. Langdon and N. T. Gladd, Comp. Phys. Comm. 87 (1995) 199

  5. Li-Ion Electrolytes with Improved Safety and Tolerance to High-Voltage Systems

    Science.gov (United States)

    Smart, Marshall C.; Bugga, Ratnakumar V.; Prakash, Surya; Krause, Frederick C.

    2013-01-01

    Given that lithium-ion (Li-ion) technology is the most viable rechargeable energy storage device for near-term applications, effort has been devoted to improving the safety characteristics of this system. Therefore, extensive effort has been devoted to developing nonflammable electrolytes to reduce the flammability of the cells/battery. A number of promising electrolytes have been developed incorporating flame-retardant additives, and have been shown to have good performance in a number of systems. However, these electrolyte formulations did not perform well when utilizing carbonaceous anodes with the high-voltage materials. Thus, further development was required to improve the compatibility. A number of Li-ion battery electrolyte formulations containing a flame-retardant additive [i.e., triphenyl phosphate (TPP)] were developed and demonstrated in high-voltage systems. These electrolytes include: (1) formulations that incorporate varying concentrations of the flame-retardant additive (from 5 to 15%), (2) the use of mono-fluoroethylene carbonate (FEC) as a co-solvent, and (3) the use of LiBOB as an electrolyte additive intended to improve the compatibility with high-voltage systems. Thus, improved safety has been provided without loss of performance in the high-voltage, high-energy system.

  6. Phosphorus Enrichment as a New Composition in the Solid Electrolyte Interphase of High-Voltage Cathodes and Its Effects on Battery Cycling

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Pengfei; Zheng, Jianming; Kuppan, Saravanan; Li, Qiuyan; Lv, Dongping; Xiao, Jie; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

    2015-11-10

    Immersion of a solid into liquid often leads to the modification of both the structure and chemistry of surface of the solid, which subsequently affects the chemical and physical properties of the system. For the case of the rechargeable lithium ion battery, such a surface modification is termed as solid electrolyte interphase (SEI) layer, which has been perceived to play critical role for the stable operation of the batteries. However, the structure and chemical composition of SEI layer and its spatial distribution and dependence on the battery operating condition remain unclear. By using aberration corrected scanning transmission electron microscopy coupled with ultra-high sensitive energy dispersive x-ray spectroscopy, we probed the structure and chemistry of SEI layer on several high voltage cathodes. We show that layer-structured cathodes, when cycled at a high cut off voltage, can form a P-rich SEI layer on their surface, which is a direct evidence of Li-salt (LiPF6) decomposition. Our systematical investigations indicate such cathode/Li-salt side reaction shows strong dependence on structure of the cathode materials, operating voltage and temperature, indicating the feasibility of SEI engineering. These findings provide us valuable insights into the complex interface between the high-voltage cathode and the electrolyte.

  7. High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

    Science.gov (United States)

    Murty, Balarama Vempaty

    2000-01-01

    A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

  8. High performance solution processed zirconium oxide gate dielectric appropriate for low temperature device application

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Musarrat; Nguyen, Manh-Cuong; Kim, Hyojin; You, Seung-Won; Jeon, Yoon-Seok; Tong, Duc-Tai; Lee, Dong-Hwi; Jeong, Jae Kyeong; Choi, Rino, E-mail: rino.choi@inha.ac.kr

    2015-08-31

    This paper reports a solution processed electrical device with zirconium oxide gate dielectric that was fabricated at a low enough temperature appropriate for flexible electronics. Both inorganic dielectric and channel materials were synthesized in the same organic solvent. The dielectric constant achieved was 13 at 250 °C with a reasonably low leakage current. The bottom gate transistor devices showed the highest mobility of 75 cm{sup 2}/V s. The device is operated at low voltage with high-k dielectric with excellent transconductance and low threshold voltage. Overall, the results highlight the potential of low temperature solution based deposition in fabricating more complicated circuits for a range of applications. - Highlights: • We develop a low temperature inorganic dielectric deposition process. • We fabricate oxide semiconductor channel devices using all-solution processes. • Same solvent is used for dielectric and oxide semiconductor deposition.

  9. Development of an intelligent high-voltage direct-current power supply for nuclear detectors

    International Nuclear Information System (INIS)

    Zhao Xiuliang

    1997-01-01

    The operation and performances of a new type direct-current high-voltage power supply are described. The power supply with intelligent feature is controlled by a single-chip microcomputer (8031), and various kinds of output voltage can be preset. The output-voltage is monitored and regulated by the single-chip microcomputer and displayed by LED. The output voltage is stable when the load current is within the allowable limits

  10. Optimization of a high voltage power supply for a nitrogen laser

    International Nuclear Information System (INIS)

    Baly, L.; Garcia, M.A.; Martin, J.L.

    1997-01-01

    In the present paper the optimization of a high voltage switching power supply for a compact TEA nitrogen laser is described. Taking as criterion the recovering of the charging voltage in a 95% of the maximal voltage, the relationships between the recovering rate coefficient, the recovering time and the maximal repetition frequency were obtained. Using an experimental set-up the power supply optimal values of turns in the primary transformer coil N p= 35 and excitation pulse frequency f exc= 25.5 kHz was determined

  11. Intense neutron source: high-voltage power supply specifications

    International Nuclear Information System (INIS)

    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

  12. High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Naoya, E-mail: naoya.iwamoto@smn.uio.no; Azarov, Alexander; Svensson, Bengt G. [Department of Physics, Center for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Ohshima, Takeshi [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292 Gunma (Japan); Moe, Anne Marie M. [Washington Mills AS, N-7300 Orkanger (Norway)

    2015-07-28

    Effects of high-temperature annealing on deep-level defects in a high-purity semi-insulating 4H silicon carbide substrate have been studied by employing current-voltage, capacitance-voltage, junction spectroscopy, and chemical impurity analysis measurements. Secondary ion mass spectrometry data reveal that the substrate contains boron with concentration in the mid 10{sup 15 }cm{sup −3} range, while other impurities including nitrogen, aluminum, titanium, vanadium and chromium are below their detection limits (typically ∼10{sup 14 }cm{sup −3}). Schottky barrier diodes fabricated on substrates annealed at 1400–1700 °C exhibit metal/p-type semiconductor behavior with a current rectification of up to 8 orders of magnitude at bias voltages of ±3 V. With increasing annealing temperature, the series resistance of the Schottky barrier diodes decreases, and the net acceptor concentration in the substrates increases approaching the chemical boron content. Admittance spectroscopy results unveil the presence of shallow boron acceptors and deep-level defects with levels in lower half of the bandgap. After the 1400 °C annealing, the boron acceptor still remains strongly compensated at room temperature by deep donor-like levels located close to mid-gap. However, the latter decrease in concentration with increasing annealing temperature and after 1700 °C, the boron acceptor is essentially uncompensated. Hence, the deep donors are decisive for the semi-insulating properties of the substrates, and their thermal evolution limits the thermal budget for device processing. The origin of the deep donors is not well-established, but substantial evidence supporting an assignment to carbon vacancies is presented.

  13. Test setup for accelerated test of high power IGBT modules with online monitoring of Vce and Vf voltage during converter operation

    DEFF Research Database (Denmark)

    de Vega, Angel Ruiz; Ghimire, Pramod; Pedersen, Kristian Bonderup

    2014-01-01

    Several accelerated test methods exist in order to study the failures mechanisms of the high power IGBT modules like temperature cycling test or power cycles based on DC current pulses. The main drawback is that the test conditions do not represent the real performance and stress conditions...... of the device in real application. The hypothesis is that ageing of power modules closer to real environment including cooling system, full dc-link voltage and continuous PWM operation could lead to more accurate study of failure mechanism. A new type of test setup is proposed, which can create different real...... load conditions like in the field. Furthermore, collector-emitter voltage (Vce) has been used as indicator of the wear-out of the high power IGBT module. The innovative monitoring system implemented in the test setup is capable of measure the Vce and forward voltage of the antiparallel diode (Vf...

  14. High Voltage GaN Schottky Rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

    1999-10-25

    Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

  15. Application of Low Voltage High Resistance Grounding in Nuclear Power Plants

    Directory of Open Access Journals (Sweden)

    Choong-Koo Chang

    2016-02-01

    Full Text Available Most nuclear power plants now utilize solid grounded low voltage systems. For safety and reliability reasons, the low voltage (LV high resistance grounding (HRG system is also increasingly used in the pulp and paper, petroleum and chemical, and semiconductor industries. Fault detection is easiest and fastest with a solidly grounded system. However, a solidly grounded system has many limitations such as severe fault damage, poor reliability on essential circuits, and electrical noise caused by the high magnitude of ground fault currents. This paper will briefly address the strengths and weaknesses of LV grounding systems. An example of a low voltage HRG system in the LV system of a nuclear power plant will be presented. The HRG system is highly recommended for LV systems of nuclear power plants if sufficient considerations are provided to prevent nuisance tripping of ground fault relays and to avoid the deterioration of system reliability.

  16. Highly efficient integrated rectifier and voltage boosting circuits for energy harvesting applications

    Directory of Open Access Journals (Sweden)

    D. Maurath

    2008-05-01

    Full Text Available This paper presents novel circuit concepts for integrated rectifiers and voltage converting interfaces for energy harvesting micro-generators. In the context of energy harvesting, usually only small voltages are supplied by vibration-driven generators. Therefore, rectification with minimum voltage losses and low reverse currents is an important issue. This is realized by novel integrated rectifiers which were fabricated and are presented in this article. Additionally, there is a crucial need for dynamic load adaptation as well as voltage up-conversion. A circuit concept is presented, which is able to obtain both requirements. This generator interface adapts its input impedance for an optimal energy transfer efficiency. Furthermore, this generator interface provides implicit voltage up-conversion, whereas the generator output energy is stored on a buffer, which is connected to the output of the voltage converting interface. As simulations express, this fully integrated converter is able to boost ac-voltages greater than |0.35 V| to an output dc-voltage of 2.0 V–2.5 V. Thereby, high harvesting efficiencies above 80% are possible within the entire operational range.

  17. 250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhan-Wen; Su, Xiao-Dong; Wei, Zhen; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Lu, Xiao-Long; Wang, Jun-Run; Yao, Ze-En, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2016-08-15

    A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

  18. Porous and mesh alumina formed by anodization of high purity aluminum films at low anodizing voltage

    International Nuclear Information System (INIS)

    Abd-Elnaiem, Alaa M.; Mebed, A.M.; El-Said, Waleed Ahmed; Abdel-Rahim, M.A.

    2014-01-01

    Electrochemical oxidation of high-purity aluminum (Al) films under low anodizing voltages (1–10) V has been conducted to obtain anodic aluminum oxide (AAO) with ultra-small pore size and inter-pore distance. Different structures of AAO have been obtained e.g. nanoporous and mesh structures. Highly regular pore arrays with small pore size and inter-pore distance have been formed in oxalic or sulfuric acids at different temperatures (22–50 °C). It is found that the pore diameter, inter-pore distance and the barrier layer thickness are independent of the anodizing parameters, which is very different from the rules of general AAO fabrication. The brand formation mechanism has been revealed by the scanning electron microscope study. Regular nanopores are formed under 10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultra-small nanopores. Anodization that is performed at voltages less than 5 V leads to mesh structured alumina. In addition, we have introduced a simple one-pot synthesis method to develop thin walls of oxide containing lithium (Li) ions that could be used for battery application based on anodization of Al films in a supersaturated mixture of lithium phosphate and phosphoric acid as matrix for Li-composite electrolyte. - Highlights: • We develop anodic aluminum oxide (AAO) with small pore size and inter-pore distance. • Applying low anodizing voltages onto aluminum film leads to form mesh structures. • The value of anodizing voltage (1–10 V) has no effect on pore size or inter-pore distance. • Applying anodizing voltage less than 5 V leads to mesh structured AAO. • AAO can be used as a matrix for Li-composite electrolytes

  19. Porous and mesh alumina formed by anodization of high purity aluminum films at low anodizing voltage

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Elnaiem, Alaa M., E-mail: alaa.abd-elnaiem@science.au.edu.eg [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Mebed, A.M. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Department of Physics, Faculty of Science, Al-Jouf University, Sakaka 2014 (Saudi Arabia); El-Said, Waleed Ahmed [Department of Chemistry, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Abdel-Rahim, M.A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt)

    2014-11-03

    Electrochemical oxidation of high-purity aluminum (Al) films under low anodizing voltages (1–10) V has been conducted to obtain anodic aluminum oxide (AAO) with ultra-small pore size and inter-pore distance. Different structures of AAO have been obtained e.g. nanoporous and mesh structures. Highly regular pore arrays with small pore size and inter-pore distance have been formed in oxalic or sulfuric acids at different temperatures (22–50 °C). It is found that the pore diameter, inter-pore distance and the barrier layer thickness are independent of the anodizing parameters, which is very different from the rules of general AAO fabrication. The brand formation mechanism has been revealed by the scanning electron microscope study. Regular nanopores are formed under 10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultra-small nanopores. Anodization that is performed at voltages less than 5 V leads to mesh structured alumina. In addition, we have introduced a simple one-pot synthesis method to develop thin walls of oxide containing lithium (Li) ions that could be used for battery application based on anodization of Al films in a supersaturated mixture of lithium phosphate and phosphoric acid as matrix for Li-composite electrolyte. - Highlights: • We develop anodic aluminum oxide (AAO) with small pore size and inter-pore distance. • Applying low anodizing voltages onto aluminum film leads to form mesh structures. • The value of anodizing voltage (1–10 V) has no effect on pore size or inter-pore distance. • Applying anodizing voltage less than 5 V leads to mesh structured AAO. • AAO can be used as a matrix for Li-composite electrolytes.

  20. High temperature energy harvesters utilizing ALN/3C-SiC composite diaphragms

    Science.gov (United States)

    Lai, Yun-Ju; Li, Wei-Chang; Felmetsger, Valery V.; Senesky, Debbie G.; Pisano, Albert P.

    2014-06-01

    Microelectromechanical systems (MEMS) energy harvesting devices aiming at powering wireless sensor systems for structural health monitoring in harsh environments are presented. For harsh environment wireless sensor systems, sensor modules are required to operate at elevated temperatures (> 250°C) with capabilities to resist harsh chemical conditions, thereby the use of battery-based power sources becomes challenging and not economically efficient if considering the required maintenance efforts. To address this issue, energy harvesting technology is proposed to replace batteries and provide a sustainable power source for the sensor systems towards autonomous harsh environment wireless sensor networks. In particular, this work demonstrates a micromachined aluminum nitride/cubic silicon carbide (AlN/3C-SiC) composite diaphragm energy harvester, which enables high temperature energy harvesting from ambient pulsed pressure sources. The fabricated device yields an output power density of 87 μW/cm2 under 1.48-psi pressure pulses at 1 kHz while connected to a 14.6-kΩ load resistor. The effects of pulse profile on output voltage have been studied, showing that the output voltage can be maximized by optimizing the diaphragm resonance frequency based on specific pulse characteristics. In addition, temperature dependence of the diaphragm resonance frequency over the range of 20°C to 600°C has been investigated and the device operation at temperatures as high as 600°C has been verified.

  1. Environmental Audits of High Voltage Objects from the View Point of Investors

    International Nuclear Information System (INIS)

    Marek Szuba, M.

    2007-01-01

    The localization of high voltage objects, e.g., overhead transmission lines, under the spatial planning and environmental protection regulations is discussed. The most important elements of the localization procedure concerning high voltage overhead lines are presented. One of the elements of this procedure is the assessment of the investment environmental impact. The environmental audit is an essential document, in which this impact is described. It seems that its scope specified in the Environmental Protection Act is not adjusted to the specificity of line investments. This gives rise to some problems in preparing environmental audits for overhead lines, e.g., possible influence of high voltage lines on the Natura 2000 area zones. Several other related problems are also highlighted in this paper. (author)

  2. AC Voltage Control of DC/DC Converters Based on Modular Multilevel Converters in Multi-Terminal High-Voltage Direct Current Transmission Systems

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-12-01

    Full Text Available The AC voltage control of a DC/DC converter based on the modular multilevel converter (MMC is considered under normal operation and during a local DC fault. By actively setting the AC voltage according to the two DC voltages of the DC/DC converter, the modulation index can be near unity, and the DC voltage is effectively utilized to output higher AC voltage. This significantly decreases submodule (SM capacitance and conduction losses of the DC/DC converter, yielding reduced capital cost, volume, and higher efficiency. Additionally, the AC voltage is limited in the controllable range of both the MMCs in the DC/DC converter; thus, over-modulation and uncontrolled currents are actively avoided. The AC voltage control of the DC/DC converter during local DC faults, i.e., standby operation, is also proposed, where only the MMC connected on the faulty cable is blocked, while the other MMC remains operational with zero AC voltage output. Thus, the capacitor voltages can be regulated at the rated value and the decrease of the SM capacitor voltages after the blocking of the DC/DC converter is avoided. Moreover, the fault can still be isolated as quickly as the conventional approach, where both MMCs are blocked and the DC/DC converter is not exposed to the risk of overcurrent. The proposed AC voltage control strategy is assessed in a three-terminal high-voltage direct current (HVDC system incorporating a DC/DC converter, and the simulation results confirm its feasibility.

  3. High energy mechano-chemical milling: Convenient approach to synthesis of LiMn1.5Ni0.5O4 high voltage cathode for lithium ion batteries

    International Nuclear Information System (INIS)

    Datta, Moni Kanchan; Ramanathan, Madhumati; Jampani, Prashanth; Saha, Partha; Epur, Rigved; Kadakia, Karan; Chung, Sung Jae; Patel, Prasad; Gattu, Bharat; Manivannan, Ayyakkannu; Kumta, Prashant N.

    2014-01-01

    Graphical abstract: Nanostructured high voltage spinel phase of LiMn 1.5 Ni 0.5 O 4 (LMNO) of particle size ∼10–40 nm has been synthesized by a cost effective high energy mechanical milling (HEMM) approach followed by low temperature thermal treatments. High energy mechanical milling of lithium and manganese oxide precursors followed by moderate heat treatment results in the formation of single phase of LMNO, the high voltage spinel phase. The nanostructured LMNO has been studied as a high voltage cathode for lithium ion rechargeable batteries. Cyclic voltammetry as well as the differential capacity plots of nanostructured LMNO show the occurrence of two major reversible reactions occurring in the potential window of ∼2–3.6 V and ∼3.6–5.1 V with an associated specific capacity ∼105 mAh/g and ∼128 mAh/g, respectively. The nanostructured LMNO synthesized by the HEMM process followed by thermal treatments at ∼773 K, ∼873 K and ∼973 K shows a reversible capacity ∼120–110 mAh/g when cycled at a rate of ∼20 mA/g (∼C/6) in the potential window ∼3.6–5.1 V. Furthermore, the nanostructured HEMM derived LMNO shows a moderate rate capability with a capacity retention ∼87 mAh/g when cycled at ∼80 mA/g (∼C) rate. - Highlights: • Generation of LiMn 1.5 Ni 0.5 O 4 (LMNO) spinel by a cost effective HEMM process. • HEMM derived LMNO spinel phase shows a capacity of ∼128 mAh/g. • HEMM derived spinel exhibits a capacity retention of ∼87 mAh/g at ∼1C rate. • SEM analysis shows good structural integrity of the cycled electrode. • Charge transfer resistance increase during cycling causes capacity fade. - Abstract: The high voltage spinel form of LiMn 1.5 Ni 0.5 O 4 (LMNO) with a particle size ∼10–40 nm has been synthesized for the first time using high energy mechanical milling (HEMM) followed by low temperature thermal treatments using Li 2 O, MnO 2 and NiO as the starting precursors. The nanostructured LMNO cathode

  4. Piezoelectric self sensing actuators for high voltage excitation

    International Nuclear Information System (INIS)

    Grasso, E; Totaro, N; Janocha, H; Naso, D

    2013-01-01

    Self sensing techniques allow the use of a piezoelectric transducer simultaneously as an actuator and as a sensor. Such techniques are based on knowledge of the transducer behaviour and on measurements of electrical quantities, in particular voltage and charge. Past research work has mainly considered the linear behaviour of piezoelectric transducers, consequently restricting the operating driving voltages to low values. In this work a new self sensing technique is proposed which is able to perform self sensing reconstruction both at low and at high driving voltages. This technique, in fact, makes use of a hysteretic model to describe the nonlinear piezoelectric capacitance necessary for self sensing reconstruction. The capacitance can be measured and identified at the antiresonances of a vibrating structure with a good approximation. After providing a mathematical background to deal with the main aspects of self sensing, this technique is compared theoretically and experimentally to a typical linear one by using an aluminum plate with one bonded self sensing transducer and a positive position feedback (PPF) controller to verify the performance in self sensing based vibration control. (paper)

  5. TiN coated aluminum electrodes for DC high voltage electron guns

    International Nuclear Information System (INIS)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-01-01

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes

  6. High-voltage measurements on the 5 ppm relative uncertainty level with collinear laser spectroscopy

    Science.gov (United States)

    Krämer, J.; König, K.; Geppert, Ch; Imgram, P.; Maaß, B.; Meisner, J.; Otten, E. W.; Passon, S.; Ratajczyk, T.; Ullmann, J.; Nörtershäuser, W.

    2018-04-01

    We present the results of high-voltage collinear laser spectroscopy measurements on the 5 ppm relative uncertainty level using a pump and probe scheme at the 4s ^2S1/2 → 4p ^2P3/2 transition of {\\hspace{0pt}}40Ca+ involving the 3d ^2D5/2 metastable state. With two-stage laser interaction and a reference measurement we can eliminate systematic effects such as differences in the contact potentials due to different electrode materials and thermoelectric voltages, and the unknown starting potential of the ions in the ion source. Voltage measurements were performed between  -5 kV and  -19 kV and parallel measurements with stable high-voltage dividers calibrated to 5 ppm relative uncertainty were used as a reference. Our measurements are compatible with the uncertainty limits of the high-voltage dividers and demonstrate an unprecedented (factor of 20) increase in the precision of direct laser-based high-voltage measurements.

  7. Effects of high voltage electrical stimulation on the rate of pH decline, meat quality and color stability in chilled beef carcasses

    OpenAIRE

    Mombeni, Ehsan Gharib; Mombeini, Manoochehr Gharib; Figueiredo, Lucas Chaves; Siqueira, Luciano Soares Jacintho; Dias, Debora Testoni

    2013-01-01

    Objective: To determine the effects of high voltage electrical stimulation (HVES, 800 Voltage) on rapid decreases in pH values and improvements in meat quality. Methods: A total of 50 beef carcasses were applied, divided into two groups, one as a control and another for HVES. Meat quality was evaluated based on M. longissimus dorsi by examining pH and temperature levels at 1, 2, 5, 10 and 24 h, while color stability was examined seven days after slaughter. Results: HVES decreased the pH...

  8. High-rate deposition of epitaxial layers for efficient low-temperature thin film epitaxial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, L.; Schmidt, J.; Wagner, T.A.; Bergmann, R.B. [Stuttgart Univ. (Germany). Inst. of Physical Electronics

    2001-07-01

    Low-temperature deposition of Si for thin-film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open-circuit voltage of these solar cells. In contrast, ion-assisted deposition produces Si films with a minority-carrier diffusion length of 40 {mu}m, obtained at a record deposition rate of 0.8 {mu}m/min and a deposition temperature of 650{sup o}C with a prebake at 810{sup o}C. A thin-film Si solar cell with a 20-{mu}m-thick epitaxial layer achieves an open-circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high-temperature solar cell process steps. (author)

  9. 75 FR 17529 - High-Voltage Continuous Mining Machine Standard for Underground Coal Mines

    Science.gov (United States)

    2010-04-06

    ... High-Voltage Continuous Mining Machine Standard for Underground Coal Mines AGENCY: Mine Safety and... of high-voltage continuous mining machines in underground coal mines. It also revises MSHA's design...-- Underground Coal Mines III. Section-by-Section Analysis A. Part 18--Electric Motor-Driven Mine Equipment and...

  10. High Efficiency Single Output ZVS-ZCS Voltage Doubled Flyback Converter

    Science.gov (United States)

    Kaliyaperumal, Deepa; Saju, Hridya Merin; Kumar, M. Vijaya

    2016-06-01

    A switch operating at high switching frequency increases the switching losses of the converter resulting in lesser efficiency. Hence this paper proposes a new topology which has resonant switches [zero voltage switching (ZVS)] in the primary circuit to eliminate the above said disadvantages, and voltage doubler zero current switching (ZCS) circuit in the secondary to double the output voltage, and hence the output power, power density and efficiency. The design aspects of the proposed topology for a single output of 5 V at 50 kHz, its simulation and hardware results are discussed in detail. The analysis of the results obtained from a 2.5 W converter reveals the superiority of the proposed converter.

  11. Calibration of the ISOLDE acceleration voltage using a high-precision voltage divider and applying collinear fast beam laser spectroscopy

    CERN Document Server

    Krieger, A.; Catherall, R.; Hochschulz, F.; Kramer, J.; Neugart, R.; Rosendahl, S.; Schipper, J.; Siesling, E.; Weinheimer, Ch.; Yordanov, D.T.; Nortershauser, W.

    2011-01-01

    A high-voltage divider with accuracy at the ppm level and collinear laser spectroscopy were used to calibrate the highvoltage installation at the radioactive ion beam facility ISOLDE at CERN. The accurate knowledge of this voltage is particularly important for collinear laser spectroscopy measurements. Beam velocity measurements using frequencycomb based collinear laser spectroscopy agree with the new calibration. Applying this, one obtains consistent results for isotope shifts of stable magnesium isotopes measured using collinear spectroscopy and laser spectroscopy on laser-cooled ions in a trap. The long-term stability and the transient behavior during recovery from a voltage dropout were investigated for the different power supplies currently applied at ISOLDE.

  12. ELABORATION OF HIGH-VOLTAGE PULSE INSTALLATIONS AND PROVIDING THEIR OPERATION PROTECTIVE MEASURES

    Directory of Open Access Journals (Sweden)

    А. М. Hashimov

    2016-01-01

    Full Text Available The article presents design engineering methods for the high-voltage pulse installations of technological purpose for disinfection of drinking water, sewage, and edible liquids by high field micro- and nanosecond pulsing exposure. Designing potentialities are considered of the principal elements of the high-voltage part and the discharge circuit of the installations towards assuring the best efficient on-load utilization of the source energy and safe operation of the high-voltage equipment. The study shows that for disinfection of drinking water and sewage it is expedient to apply microsecond pulse actions causing the electrohydraulic effect in aqueous media with associated complex of physical processes (ultraviolet emission, generation of ozone and atomic oxygen, mechanical compression waves, etc. having detrimental effect on life activity of the microorganisms. In case of disinfecting edible liquids it is recommended to use the nanosecond pulses capable of straight permeating the biological cell nucleus, inactivating it. Meanwhile, the nutritive and biological values of the foodstuffs are saved and their organoleptic properties are improved. It is noted that in elaboration process of high-frequency pulse installations special consideration should be given to issues of the operating personnel safety discipline and securing conditions for the entire installation uninterrupted performance. With this objective in view the necessary requirements should be fulfilled on shielding the high- and low-voltage installation parts against high-frequency electromagnetic emissions registered by special differential sensors. Simultaneously, the abatement measures should be applied on the high-voltage equipment operational noise level. The authors offer a technique for noise abatement to admissible levels (lower than 80 dB A by means of coating the inside surface with shielded enclosure of densely-packed abutting sheets of porous electro-acoustic insulating

  13. Solar photovoltaic charging of high voltage nickel metal hydride batteries using DC power conversion

    Science.gov (United States)

    Kelly, Nelson A.; Gibson, Thomas L.

    There are an increasing number of vehicle choices available that utilize batteries and electric motors to reduce tailpipe emissions and increase fuel economy. The eventual production of electricity and hydrogen in a renewable fashion, such as using solar energy, can achieve the long-term vision of having no tailpipe environmental impact, as well as eliminating the dependence of the transportation sector on dwindling supplies of petroleum for its energy. In this report we will demonstrate the solar-powered charging of the high-voltage nickel-metal hydride (NiMH) battery used in the GM 2-mode hybrid system. In previous studies we have used low-voltage solar modules to produce hydrogen via the electrolysis of water and to directly charge lithium-ion battery modules. Our strategy in the present work was to boost low-voltage PV voltage to over 300 V using DC-DC converters in order to charge the high-voltage NiMH battery, and to regulate the battery charging using software to program the electronic control unit supplied with the battery pack. A protocol for high-voltage battery charging was developed, and the solar to battery charging efficiency was measured under a variety of conditions. We believe this is the first time such high-voltage batteries have been charged using solar energy in order to prove the concept of efficient, solar-powered charging for battery-electric vehicles.

  14. Design of full digital 50 kV electronic gun high voltage power supply

    International Nuclear Information System (INIS)

    Ge Lei; Shang Lei

    2014-01-01

    The design of full digital electronic gun high voltage power supply based on DSP was introduced in this paper. This power supply has innovations of full digital feedback circuit and PID closed-loop control mode. The application of high frequency resonant converter circuit reduces the size of the resonant element and transformer. The current-coupling distributed high voltage transformer and rectifier circuit were employed in this power supply. By this way, the power supply efficiency is improved and the number of distributed parameters is reduced, and the rectifier circuit could work under the oil-free environment. This power supply has been used in electronic grid-control high voltage system of the irradiation accelerator. (authors)

  15. MAGY: An innovative high voltage-low current power supply for gyrotron

    International Nuclear Information System (INIS)

    Siravo, Ugo; Alex, Juergen; Bader, Michael; Carpita, Mauro; Fasel, Damien; Gavin, Serge; Perez, Albert

    2011-01-01

    From the electrical point of view, the body and the anode of high power gyrotrons behave as capacitive loads. A highly dynamic power supply is, therefore, hard to achieve. The MAGY concept (Modulator for the Anode of a triode type GYrotron) embodies an innovative solution to manage the capacitive current ensuring a very low ripple on the output voltage. It consists of a series of independent, bi-directional and regulated DC sources. Compared to existing topologies, this solution requires a smaller number of power modules. It avoids internal high frequency modulation and simultaneously offers high resolution of the output voltage and a wide range of operating scenarios.

  16. Studies of dislocation loops produced by irradiation of ZnO in a high-voltage electron microscope

    International Nuclear Information System (INIS)

    Yoshiie, T.; Iwanaga, H.; Shibata, N.; Suzuki, K.; Takeuchi, S.

    1980-01-01

    Electron-irradiation studies on vapour-grown ZnO ribbon crystals have been carried out in situ in a high-voltage electron microscope. Dislocation loops nucleate both on stacking-fault planes and in the matrix by irradiation with electron accelerated through voltages higher than 700 kV at room temperature. Two types of loops with the Burgers vectors b=1/2c and b=a exist in the matrix, where a=1/3 and c=[0001]. On the other hand, loops with b=1/2c+a/3 and those with b=1/2c are formed on the prismatic fault planes and basal fault planes, respectively. Diffraction-contrast experiments show these loops to be of interstitial type. A re-irradiation experiment after the annealing indicates a possibility that there exist vacancies in the matrix at 700 0 C. (author)

  17. Radiation Damage Observations in the ATLAS Pixel Detector Using the High Voltage Delivery System

    CERN Document Server

    Toms, K

    2011-01-01

    We describe the implementation of radiation damage monitoring using leakage current measurement of the silicon pixel sensors provided by the circuits of the ATLAS Pixel Detector high voltage delivery (HVPP4) system. The dependence of the leakage current upon the integrated luminosity for several temperature scenarios is presented. Based on the analysis we have determined the sensitivity specifications for a Current Measurement System. The status of the system and the first measurement of the radiation damage corresponding to 2--4 fb$^{-1}$ of integrated luminosity are presented, as well as the comparison with the theoretical model.

  18. High-voltage pulsed life of multistressed polypropylene capacitor dielectric

    International Nuclear Information System (INIS)

    Laghari, J.R.

    1992-01-01

    High-voltage polypropylene capacitors were aged under singular as well as simultaneous multiple stresses (electrical, thermal, and radiation) at the University of Buffalo's 2 MW thermal nuclear reactor. These stresses were combined neutron-gamma radiation with a total dose of 1.6 x 10 6 rad, electrical stress at 40 V rms /μm, and thermal stress at 90 degrees C. After exposure, the polypropylene dielectric was tested for life (number of pulses to fail) under high-voltage high-repetition-rate (100 pps) pulses. Pulsed life data were also compared with ac life data. Results show that radiation stress causes the most degradation in life, either acting alone or in combination with other stresses. The largest reduction in life occurs when polypropylene is aged under simultaneous multiple stresses (electrical, thermal, and radiation). In this paper, it is shown that pulsed life can be equivalently compared with ac life

  19. Energy Storage Options for Voltage Support in Low-Voltage Grids with High Penetration of Photovoltaic

    DEFF Research Database (Denmark)

    Marra, Francesco; Tarek Fawzy, Y.; Bülo, Thorsten

    2012-01-01

    to be established. In the long term, these solutions should also aim to allow further more PV installed capacity, while meeting the power quality requirements. In this paper, different concepts of energy storage are proposed to ensure the voltage quality requirements in a LV grid with high PV penetration...

  20. An analytic current-voltage model for quasi-ballistic III-nitride high electron mobility transistors

    Science.gov (United States)

    Li, Kexin; Rakheja, Shaloo

    2018-05-01

    We present an analytic model to describe the DC current-voltage (I-V) relationship in scaled III-nitride high electron mobility transistors (HEMTs) in which transport within the channel is quasi-ballistic in nature. Following Landauer's transport theory and charge calculation based on two-dimensional electrostatics that incorporates negative momenta states from the drain terminal, an analytic expression for current as a function of terminal voltages is developed. The model interprets the non-linearity of access regions in non-self-aligned HEMTs. Effects of Joule heating with temperature-dependent thermal conductivity are incorporated in the model in a self-consistent manner. With a total of 26 input parameters, the analytic model offers reduced empiricism compared to existing GaN HEMT models. To verify the model, experimental I-V data of InAlN/GaN with InGaN back-barrier HEMTs with channel lengths of 42 and 105 nm are considered. Additionally, the model is validated against numerical I-V data obtained from DC hydrodynamic simulations of an unintentionally doped AlGaN-on-GaN HEMT with 50-nm gate length. The model is also verified against pulsed I-V measurements of a 150-nm T-gate GaN HEMT. Excellent agreement between the model and experimental and numerical results for output current, transconductance, and output conductance is demonstrated over a broad range of bias and temperature conditions.

  1. The high voltage system for the novel MPGD-based photon detectors of COMPASS RICH-1

    CERN Document Server

    Dalla Torre, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Chatterjee, C.; Ciliberti, P.; Dasgupta, S.; Gobbo, B.; Gregori, M.; Hamar, G.; Levorato, S.; Martin, A.; Menon, G.; Tessarotto, F.; Zhao, Y.

    2018-01-01

    The architecture of the novel MPGD-based photon detectors of COMPASS RICH-1 consists in a large-size hybrid MPGD multilayer layout combining two layers of Thick-GEMs and a bulk resistive MICROMEGAS. Concerning biasing voltage, the Thick-GEMs are segmented in order to reduce the energy released in case of occasional discharges, while the MICROMEGAS anode is segmented in pads individually biased at positive voltage, while the micromesh is grounded. In total, there are ten different electrode types and more than 20000 electrodes supplied by more than 100 HV channels. Commercial power supply units are used. The original elements of the power supply system are the architecture of the voltage distribution net, the compensation, by voltage adjustment, of the effects of pressure and temperature variation affecting the detector gain and a sophisticated control software, which allows to protect the detectors against errors by the operator, to monitor and log voltages and current at 1 Hz rate and to automatically react ...

  2. High-Voltage Clock Driver for Photon-Counting CCD Characterization

    Science.gov (United States)

    Baker, Robert

    2013-01-01

    A document discusses the CCD97 from e2v technologies as it is being evaluated at Goddard Space Flight Center's Detector Characterization Laboratory (DCL) for possible use in ultra-low background noise space astronomy applications, such as Terrestrial Planet Finder Coronagraph (TPF-C). The CCD97 includes a photoncounting mode where the equivalent output noise is less than one electron. Use of this mode requires a clock signal at a voltage level greater than the level achievable by the existing CCD (charge-coupled-device) electronics. A high-voltage waveform generator has been developed in code 660/601 to support the CCD97 evaluation. The unit generates required clock waveforms at voltage levels from -20 to +50 V. It deals with standard and arbitrary waveforms and supports pixel rates from 50 to 500 kHz. The system is designed to interface with existing Leach CCD electronics.

  3. HVPTF-The high voltage laboratory for the ITER Neutral Beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    De Lorenzi, A., E-mail: antonio.delorenzi@igi.cnr.it [Consorzio RFX-Associazione EURATOM-ENEA per la Fusione Corso Stati Uniti 4, 35127 Padova (Italy); Pilan, N.; Lotto, L.; Fincato, M. [Consorzio RFX-Associazione EURATOM-ENEA per la Fusione Corso Stati Uniti 4, 35127 Padova (Italy); Pesavento, G.; Gobbo, R. [DIE, Universita di Padova, Via Gradenigo 6A, I-35100 Padova (Italy)

    2011-10-15

    In the MITICA research program for the construction of the ITER Neutral Beam Injector prototype, a Laboratory for the investigation on high voltage holding in vacuum has been set up. This Laboratory - HVPTF: High Voltage Padova Test Facility - is presently capable of experiments up to 300 kV dc, and planned for the upgrade to 800 kV. The specific mission for this ancillary lab is the support to the electrostatic design and construction of the MITICA accelerator and the development and testing of HV components to be installed inside the MITICA accelerator during its operation. The paper describes the structure of the lab, characterized by a high degree of automation and reports the results of the commissioning at 300 kV and the first results of voltage holding between test electrodes.

  4. HVPTF-The high voltage laboratory for the ITER Neutral Beam test facility

    International Nuclear Information System (INIS)

    De Lorenzi, A.; Pilan, N.; Lotto, L.; Fincato, M.; Pesavento, G.; Gobbo, R.

    2011-01-01

    In the MITICA research program for the construction of the ITER Neutral Beam Injector prototype, a Laboratory for the investigation on high voltage holding in vacuum has been set up. This Laboratory - HVPTF: High Voltage Padova Test Facility - is presently capable of experiments up to 300 kV dc, and planned for the upgrade to 800 kV. The specific mission for this ancillary lab is the support to the electrostatic design and construction of the MITICA accelerator and the development and testing of HV components to be installed inside the MITICA accelerator during its operation. The paper describes the structure of the lab, characterized by a high degree of automation and reports the results of the commissioning at 300 kV and the first results of voltage holding between test electrodes.

  5. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11 000 cm2/V·s

    KAUST Repository

    Smith, Casey; Qaisi, Ramy M.; Liu, Zhihong; Yu, Qingkai; Hussain, Muhammad Mustafa

    2013-01-01

    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11 000 cm 2/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low t ox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance. © 2013 American Chemical Society.

  6. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11 000 cm2/V·s

    KAUST Repository

    Smith, Casey

    2013-07-23

    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11 000 cm 2/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low t ox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance. © 2013 American Chemical Society.

  7. Kinetics of charged particles in a high-voltage gas discharge in a nonuniform electrostatic field

    Energy Technology Data Exchange (ETDEWEB)

    Kolpakov, V. A., E-mail: kolpakov683@gmail.com; Krichevskii, S. V.; Markushin, M. A. [Korolev Samara National Research University (Russian Federation)

    2017-01-15

    A high-voltage gas discharge is of interest as a possible means of generating directed flows of low-temperature plasma in the off-electrode space distinguished by its original features [1–4]. We propose a model for calculating the trajectories of charges particles in a high-voltage gas discharge in nitrogen at a pressure of 0.15 Torr existing in a nonuniform electrostatic field and the strength of this field. Based on the results of our calculations, we supplement and refine the extensive experimental data concerning the investigation of such a discharge published in [1, 2, 5–8]; good agreement between the theory and experiment has been achieved. The discharge burning is initiated and maintained through bulk electron-impact ionization and ion–electron emission. We have determined the sizes of the cathode surface regions responsible for these processes, including the sizes of the axial zone involved in the discharge generation. The main effect determining the kinetics of charged particles consists in a sharp decrease in the strength of the field under consideration outside the interelectrode space, which allows a free motion of charges with specific energies and trajectories to be generated in it. The simulation results confirm that complex electrode systems that allow directed plasma flows to be generated at a discharge current of hundreds or thousands of milliamperes and a voltage on the electrodes of 0.3–1 kV can be implemented in practice [3, 9, 10].

  8. Radio and television interference caused by corona discharges from high-voltage transmission lines

    International Nuclear Information System (INIS)

    Sarmadi, M.

    1996-01-01

    Increase in power utility loads in industrialized countries, as well as developing countries, demands a higher level of transmission line voltage. Radio interference (RI) problems have been determined to be a limiting factor in selecting the size of transmission line conductors. Transmission line noise is primarily caused by corona discharges in the immediate vicinity of the conductor. It has been observed that discharges occur during both half-cycles of the applied voltage, but positive corona is usually predominant at AM radio frequencies range with practical high-voltage and extra high-voltage transmission lines. The corona radio noise effect is highly dependent upon the presence of particles on the surface of the conductor and the increase of the electrical gradient beyond the breakdown value of the air. Therefore, corona radio noise varies significantly with the weather and atmospheric conditions and generally increases by 10 to 30 dB in foul weather

  9. Cavallo's multiplier for in situ generation of high voltage

    Science.gov (United States)

    Clayton, S. M.; Ito, T. M.; Ramsey, J. C.; Wei, W.; Blatnik, M. A.; Filippone, B. W.; Seidel, G. M.

    2018-05-01

    A classic electrostatic induction machine, Cavallo's multiplier, is suggested for in situ production of very high voltage in cryogenic environments. The device is suitable for generating a large electrostatic field under conditions of very small load current. Operation of the Cavallo multiplier is analyzed, with quantitative description in terms of mutual capacitances between electrodes in the system. A demonstration apparatus was constructed, and measured voltages are compared to predictions based on measured capacitances in the system. The simplicity of the Cavallo multiplier makes it amenable to electrostatic analysis using finite element software, and electrode shapes can be optimized to take advantage of a high dielectric strength medium such as liquid helium. A design study is presented for a Cavallo multiplier in a large-scale, cryogenic experiment to measure the neutron electric dipole moment.

  10. High voltage processing of the SLC polarized electron gun

    International Nuclear Information System (INIS)

    Saez, P.; Clendenin, J.; Garden, C.; Hoyt, E.; Klaisner, L.; Prescott, C.; Schultz, D.; Tang, H.

    1993-04-01

    The SLC polarized electron gun operates at 120 kV with very low dark current to maintain the ultra high vacuum (UHV). This strict requirement protects the extremely sensitive photocathode from contaminants caused by high voltage (HV) activity. Thorough HV processing is thus required x-ray sensitive photographic film, a nanoammeter in series with gun power supply, a radiation meter, a sensitive residual gas analyzer and surface x-ray spectrometry were used to study areas in the gun where HV activity occurred. By reducing the electric field gradients, carefully preparing the HV surfaces and adhering to very strict clean assembly procedures, we found it possible to process the gun so as to reduce both the dark current at operating voltage and the probability of HV discharge. These HV preparation and processing techniques are described

  11. A high open-circuit voltage gallium nitride betavoltaic microbattery

    International Nuclear Information System (INIS)

    Cheng, Zaijun; Chen, Xuyuan; San, Haisheng; Feng, Zhihong; Liu, Bo

    2012-01-01

    A high open-circuit voltage betavoltaic microbattery based on a gallium nitride (GaN) p–i–n homojunction is demonstrated. As a beta-absorbing layer, the low electron concentration of the n-type GaN layer is achieved by the process of Fe compensation doping. Under the irradiation of a planar solid 63 Ni source with activity of 0.5 mCi, the open-circuit voltage of the fabricated microbattery with 2 × 2 mm 2 area reaches as much as 1.64 V, which is the record value reported for betavoltaic batteries with 63 Ni source, the short-circuit current was measured as 568 pA and the conversion effective of 0.98% was obtained. The experimental results suggest that GaN is a high-potential candidate for developing the betavoltaic microbattery. (paper)

  12. Simulation of cold plasma in a chamber under high- and low-frequency voltage conditions for a capacitively coupled plasma

    Institute of Scientific and Technical Information of China (English)

    Hao Daoxin; Cheng Jia; Ji Linhong; Sun Yuchun

    2012-01-01

    The characteristics of cold plasma,especially for a dual-frequency capacitively coupled plasma (CCP),play an important role for plasma enhanced chemical vapor deposition,which stimulates further studies using different methods.In this paper,a 2D fluid model was constructed for N2 gas plasma simulations with CFD-ACE+,a commercial multi-physical software package.First,the distributions of electric potential (Epot),electron number density (Ne),N number density (N) and electron temperature (Te) are described under the condition of high frequency (HF),13.56 MHz,HF voltage,300 V,and low-frequency (LF) voltage,0 V,particularly in the sheath.Based on this,the influence of HF on Ne is further discussed under different HF voltages of 200 V,300 V,400 V,separately,along with the influence of LF,0.3 MHz,and various LF voltages of 500 V,600 V,700 V.The results show that sheaths of about 3 mm are formed near the two electrodes,in which Epot and Te vary extensively with time and space,while in the plasma bulk Epot changes synchronously with an electric potential of about 70 V and Te varies only in a small range.N is also modulated by the radio frequency,but the relative change in N is small.Ne varies only in the sheath,while in the bulk it is steady at different time steps.So,by comparing Ne in the plasma bulk at the steady state,we can see that Ne will increase when HF voltage increases.Yet,Ne will slightly decrease with the increase of LF voltage.At the same time,the homogeneity will change in both x and y directions.So both HF and LF voltages should be carefully considered in order to obtain a high-density,homogeneous plasma.

  13. High voltage performance of a dc photoemission electron gun with centrifugal barrel-polished electrodes

    Science.gov (United States)

    Hernandez-Garcia, C.; Bullard, D.; Hannon, F.; Wang, Y.; Poelker, M.

    2017-09-01

    The design and fabrication of electrodes for direct current (dc) high voltage photoemission electron guns can significantly influence their performance, most notably in terms of maximum achievable bias voltage. Proper electrostatic design of the triple-point junction shield electrode minimizes the risk of electrical breakdown (arcing) along the insulator-cable plug interface, while the electrode shape is designed to maintain work, we describe a centrifugal barrel-polishing technique commonly used for polishing the interior surface of superconducting radio frequency cavities but implemented here for the first time to polish electrodes for dc high voltage photoguns. The technique reduced polishing time from weeks to hours while providing surface roughness comparable to that obtained with diamond-paste polishing and with unprecedented consistency between different electrode samples. We present electrode design considerations and high voltage conditioning results to 360 kV (˜11 MV/m), comparing barrel-polished electrode performance to that of diamond-paste polished electrodes. Tests were performed using a dc high voltage photogun with an inverted-geometry ceramic insulator design.

  14. Negative-feedback control system of the high voltage power supply for ECRH

    International Nuclear Information System (INIS)

    Ding Tonghai; Liu Baohua; Jiang Shufang

    2001-01-01

    A kind of high accuracy negative high voltage power supply (HVPS) was introduced. The serial feedback was regulated according to the character of the high power tetrode and a new kind of integrator with preset value, which solved the key technological problem of the HVPS that the ECRH system required a voltage of -80 kV, a pulse width of 10 - 100 ms and a precision of 99.7%. The result using a PSPICE code simulation has shown that the method is practical

  15. A New Approach to High Efficincy in Isolated Boost Converters for High-Power Low-Voltage Fuel Cell Apllications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.

    2008-01-01

    A new low-leakage-inductance low-resistance design approach to low-voltage high-power isolated boost converters is presented. Very low levels of parasitic circuit inductances are achieved by optimizing transformer design and circuit lay-out. Primary side voltage clamp circuits can be eliminated...... by the use of power MOSFETs fully rated for repetitive avalanche. Voltage rating of primary switches can now be reduced, significantly reducing switch on-state losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Test results from a 1.5 kW full-bridge boost...... converter verify theoretical analysis and demonstrate very high efficiency. Worst case efficiency, at minimum input voltage maximum power, is 96.8 percent and maximum efficiency reaches 98 percent....

  16. Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells.

    Science.gov (United States)

    Li, Yinshi; Sun, Xianda; Feng, Ying

    2017-05-22

    Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm -2 , an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH - ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Digital measurement system for the LHC klystron high voltage modulator.

    CERN Document Server

    Mikkelsen, Anders

    Accelerating voltage in the Large Hadron Collider (LHC) is created by a means of 16 superconducting standing wave RF cavities, each fed by a 400MHz/300kW continuous wave klystron amplifier. Part of the upgrade program for the LHC long shutdown one is to replace the obsolete analogue current and voltage measurement circuitry located in the high voltage bunkers by a new, digital system, using ADCs and optical fibres. A digital measurement card is implemented and integrated into the current HV modulator oil tank (floating at -58kV) and interfaced to the existing digital VME boards collecting the data for several klystrons at the ground potential. Measured signals are stored for the logging, diagnostics and post-mortem analysis purposes.

  18. High voltage tests of an electrostatic accelerator for different mixtures of gases at various pressures

    International Nuclear Information System (INIS)

    Hellborg, R.

    1996-01-01

    An account is given of high voltage tests of an electrostatic accelerator. High voltage conditioning is measured and is reported for the same accelerator tube after different periods of usage. Tests of different mixtures of sulphur hexafluoride and nitrogen have been performed. A considerable amount of data was obtained for various parameters connected with the high voltage system for different proportions of nitrogen in sulphur hexafluoride at various gas pressures. (orig.)

  19. New non-linear control strategy for non-isolated DC/DC converter with high voltage ratio

    Energy Technology Data Exchange (ETDEWEB)

    Shahin, A.; Huang, B.; Martin, J.P.; Pierfederici, S.; Davat, B. [Groupe de Recherche en Electronique et en Electrotechnique de Nancy - INPL - Nancy Universite, 2, Avenue de la Foret de Haye, 54516 Vandoeuvre-les-Nancy Cedex (France)

    2010-01-15

    In this paper, a non-isolated DC/DC converter with high voltage ratio is proposed to allow the interface between a low voltage power source like fuel cell and a high voltage DC bus. To take into account the low voltage-high density characteristics of power sources, a cascaded structure composed of two sub-converters has been chosen and allows obtaining a high voltage ratio. The choice of each sub-converter is based on the requirements of the source and its performances. Consequently, we have chosen a three-interleaved boost converter as the 1st sub-converter whereas the 2nd sub-converter is a three-level boost converter. The control of the whole system is realized thanks to energetic trajectories planning based on flatness properties of the system. The control of both the current and the balance of voltage across the output serial capacitors of the three-level boost converter is ensured by non-linear controllers based on a new non-linear model. Experimental results allow validating the proposed power architecture and its associated control. (author)

  20. New non-linear control strategy for non-isolated DC/DC converter with high voltage ratio

    International Nuclear Information System (INIS)

    Shahin, A.; Huang, B.; Martin, J.P.; Pierfederici, S.; Davat, B.

    2010-01-01

    In this paper, a non-isolated DC/DC converter with high voltage ratio is proposed to allow the interface between a low voltage power source like fuel cell and a high voltage DC bus. To take into account the low voltage-high density characteristics of power sources, a cascaded structure composed of two sub-converters has been chosen and allows obtaining a high voltage ratio. The choice of each sub-converter is based on the requirements of the source and its performances. Consequently, we have chosen a three-interleaved boost converter as the 1st sub-converter whereas the 2nd sub-converter is a three-level boost converter. The control of the whole system is realized thanks to energetic trajectories planning based on flatness properties of the system. The control of both the current and the balance of voltage across the output serial capacitors of the three-level boost converter is ensured by non-linear controllers based on a new non-linear model. Experimental results allow validating the proposed power architecture and its associated control.

  1. Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

    Science.gov (United States)

    She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

    2016-12-13

    A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

  2. Design and validation of a high-voltage levitation circuit for electrostatic accelerometers

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.; Wu, S. C.; Zhou, Z. B.; Bai, Y. Z.; Hu, M.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurements, School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2013-12-15

    A simple high-voltage circuit with a voltage range of 0 to 900 V and an open-loop bandwidth of 11 kHz is realized by using an operational amplifier and a MOSFET combination. The circuit is used for the levitation of a test mass of 71 g, suspended below the top-electrodes with a gap distance of 57 μm, so that the performance of an electrostatic accelerometer can be tested on the ground. The translation noise of the accelerometer, limited by seismic noise, is about 4 × 10{sup −8} m/s{sup 2}/Hz{sup 1/2} at 0.1 Hz, while the high-voltage coupling noise is one-order of magnitude lower.

  3. High voltage nanosecond generator with pulse repetition rate of 1,000 p.p.s.

    Energy Technology Data Exchange (ETDEWEB)

    Gubanov, V P; Korovin, S D; Stepchenko, A S [High Current Electronics Institute, Tomsk (Russian Federation)

    1997-12-31

    A compact high voltage nanosecond generator is described with a pulse repetition rate up to 1000 p.p.s. The generator includes a 30-Ohm coaxial forming line charged by a built-in Tesla transformer with a high coupling coefficient, and a high voltage (N{sub 2}) gas gap switch with gas blowing between the electrodes. The maximum forming line charge voltage is 450 kV, the pulse duration is about 4 ns, and its amplitude for a matched load is up to 200 kV. (author). 3 figs., 9 refs.

  4. Source of high-voltage power supply for ozone generators at glow discharge

    International Nuclear Information System (INIS)

    Bruev, A.A.; Golota, V.I.; Zavada, L.M.; Taran, G.V.

    2000-01-01

    High-voltage power supply source on quasi-resonance inverter base which works at direct current regime is described. This source forms 20 kV voltage with 0 - 10 mA current regulation. It protects the source from current break-downs and feeds ozone generators at glow discharge

  5. [High voltage accidents, characteristics and treatment].

    Science.gov (United States)

    Hülsbergen-Krüger, S; Pitzler, D; Partecke, B D

    1995-04-01

    High-voltage injuries cause localised entrance and exit burns, extensive arc, flame and flash burns and, even more dangerous, necrosis of the underlying muscles on the pathway of the current through the body. Therefore it should be recognized that the ensuing disease is more like a crush injury than a thermal burn. The extent of injury cannot be judged by the percentage and depth of the skin burn. Diagnostic fasciotomies, radical debridement, and in many cases early amputation are necessary to prevent life-threatening complications. Over a period of 10 years, 43 patients with high-voltage injuries have been treated at the Hamburg Burn Center, 36 of them in primary care. Common causes of injury were accidents in railway areas (28%), using portable aluminium ladders near overhead power lines (9.3%), and working on electrical equipment (30.2%). Six of the primary care patients died (16.6%), and 34.9% had an amputation of one or more extremities. Nearly all patients underwent several debridement and split-skin graft procedures. In 30% of cases additional free and pedicled flaps were needed to cover soft tissue defects. Ten patients (23.3%) sustained fractures and other injuries from falls, seven (16.3%) of them severe polytrauma. Initial cardiac arrhythmics were diagnosed in 16.6% of the primarily treated patients. Thirty per cent of our patients had neurological complications such as peripheral paresis, tetraplegia and paraplegia, 20.7% of these caused solely by the electric current.

  6. Low-temperature VRH conduction through complex materials in the presence of a temperature-dependent voltage threshold: A semi-classical percolative approach

    International Nuclear Information System (INIS)

    Sen, A.K.; Bhattacharya, S.

    2006-12-01

    In this paper, we study the variation of low temperature (T) dc conductance, G(T), of a semi-classical percolative Random Resistor cum Tunneling-bond Network (RRTN), in the presence of a linearly temperature-dependent microscopic voltage threshold, υ g (T). This model (proposed by our group in the early 90's) considers a phenomenological semi-classical tunneling (or, hopping through a barrier) process. Just as in our previous constant-υ g case, we find in the present study also that the variable range hopping (VRH) exponent γ varies continuously with the ohmic concentration p in a non-monotonic fashion. In addition, we observe a new shoulder-like behaviour of G(T) in the intermediate temperature range, below the conductance maximum. (author)

  7. Temperature dependent microwave performance of AlGaN/GaN high-electron-mobility transistors on high-resistivity silicon substrate

    International Nuclear Information System (INIS)

    Arulkumaran, S.; Liu, Z.H.; Ng, G.I.; Cheong, W.C.; Zeng, R.; Bu, J.; Wang, H.; Radhakrishnan, K.; Tan, C.L.

    2007-01-01

    The influence of temperature (- 50 deg. C to + 200 deg. C) was studied on the DC and microwave characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) on high resistivity Si substrate for the first time. The AlGaN/GaN HEMTs exhibited a current-gain cut-off frequency (f T ) of 11.8 GHz and maximum frequency of oscillation (f max ) of 27.5 GHz. When compared to room temperature values, about 4% and 10% increase in f T and f max and 23% and 39.5% decrease in f T and f max were observed when measured at - 50 deg. C and 200 deg. C, respectively. The improvement of I D , g m f T , and f max at - 50 deg. C is due to the enhancement of 2DEG mobility and effective electron velocity. The anomalous drain current reduction in the I-V curves were observed at low voltage region at the temperature ≤ 10 deg. C but disappeared when the temperature reached ≥ 25 deg. C. A positive threshold voltage (V th ) shift was observed from - 50 deg. C to 200 deg. C. The positive shift of V th is due to the occurrence of trapping effects in the devices. The drain leakage current decreases with activation energies of 0.028 eV and 0.068 eV. This decrease of leakage current with the increase of temperature is due to the shallow acceptor initiated impact ionization

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

    International Nuclear Information System (INIS)

    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)

  9. Construction of control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen

    International Nuclear Information System (INIS)

    Saminto; Eko Priyono; Sugeng Riyanto

    2013-01-01

    A control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen have been made. This device consists of the software and hardware component. Hardware component consists of SCR phase angle controller LPC-50HDA type, T100MD1616+ PLC, high voltage transformer and voltage rectifier system. Software component used a LADDER program and TBasic serves to control of the high voltage output. The components in these devices have been tested in the double chamber plasma nitrogen. Its performance meet with the design criteria that can supply of plasma nitrogen operation voltage in the range 290 Vdc to 851 Vdc with glow discharge current 0.4 A to 1.4 A. In general it can be said that the control and instrumentation devices of high voltage power supply is ready for use at the double chamber plasma nitrogen device. (author)

  10. Irreversible electroporation ablation area enhanced by synergistic high- and low-voltage pulses.

    Directory of Open Access Journals (Sweden)

    Chenguo Yao

    Full Text Available Irreversible electroporation (IRE produced by a pulsed electric field can ablate tissue. In this study, we achieved an enhancement in ablation area by using a combination of short high-voltage pulses (HVPs to create a large electroporated area and long low-voltage pulses (LVPs to ablate the electroporated area. The experiments were conducted in potato tuber slices. Slices were ablated with an array of four pairs of parallel steel electrodes using one of the following four electric pulse protocols: HVP, LVP, synergistic HVP+LVP (SHLVP or LVP+HVP. Our results showed that the SHLVPs more effectively necrotized tissue than either the HVPs or LVPs, even when the SHLVP dose was the same as or lower than the HVP or LVP doses. The HVP and LVP order mattered and only HVPs+LVPs (SHLVPs treatments increased the size of the ablation zone because the HVPs created a large electroporated area that was more susceptible to the subsequent LVPs. Real-time temperature change monitoring confirmed that the tissue was non-thermally ablated by the electric pulses. Theoretical calculations of the synergistic effects of the SHLVPs on tissue ablation were performed. Our proposed SHLVP protocol provides options for tissue ablation and may be applied to optimize the current clinical IRE protocols.

  11. Irreversible electroporation ablation area enhanced by synergistic high- and low-voltage pulses.

    Science.gov (United States)

    Yao, Chenguo; Lv, Yanpeng; Dong, Shoulong; Zhao, Yajun; Liu, Hongmei

    2017-01-01

    Irreversible electroporation (IRE) produced by a pulsed electric field can ablate tissue. In this study, we achieved an enhancement in ablation area by using a combination of short high-voltage pulses (HVPs) to create a large electroporated area and long low-voltage pulses (LVPs) to ablate the electroporated area. The experiments were conducted in potato tuber slices. Slices were ablated with an array of four pairs of parallel steel electrodes using one of the following four electric pulse protocols: HVP, LVP, synergistic HVP+LVP (SHLVP) or LVP+HVP. Our results showed that the SHLVPs more effectively necrotized tissue than either the HVPs or LVPs, even when the SHLVP dose was the same as or lower than the HVP or LVP doses. The HVP and LVP order mattered and only HVPs+LVPs (SHLVPs) treatments increased the size of the ablation zone because the HVPs created a large electroporated area that was more susceptible to the subsequent LVPs. Real-time temperature change monitoring confirmed that the tissue was non-thermally ablated by the electric pulses. Theoretical calculations of the synergistic effects of the SHLVPs on tissue ablation were performed. Our proposed SHLVP protocol provides options for tissue ablation and may be applied to optimize the current clinical IRE protocols.

  12. Design and performance of a 2-megawatt high voltage dc test load

    International Nuclear Information System (INIS)

    Horan, D.; Kustom, R.; Ferguson, M.

    1994-01-01

    A high-power water-cooled resistive load which simulates the electrical load characteristics of a high-power klystron, capable of a 2 MW dissipation at 95 kV DC, is designed and installed. The load utilizes wirewound resistor elements suspended inside G-11 insulated tubing contained within a single-wall 316 stainless steel pressure vessel with flanged elliptical heads. The vessel supplies a continuous flow of deionized water. Baffles fabricated from G-10 sheets support the tubing and promote water turbulence to maximize heat removal. A companion oil tank houses resistive filament and mod-anode power supply test loads, plus an electrical interlock system which provides protection from inadequate water flow, excessive oil temperature, and arcing in either the pressure vessel or oil tank. A secondary safety system consists of both hydrostatic and steam pressure relief valves on the pressure vessel. Power supply tests indicate the load simulates the electrical load characteristics of a high-power klystron to a degree sufficient to accurately performance-test the rf high voltage power supplies used at the Advanced Photon Source

  13. Design of the all solid high-voltage power supply for a gyrotron body

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Yihua [School of Mathematics and Physics, University of South China, Hengyang, 421001 (China); Chen, Wenguang, E-mail: 430000485393@usc.edu.cn [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Hu, Bo [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Rao, Jun; Huang, Mei; Kang, Zihua; Feng, Kun [Southwestern Institute of Physics, Chengdu, 610041 (China); Huang, Jiaqi [School of Electrical Engineering, University of South China, Hengyang, 421001 (China)

    2017-04-15

    Highlights: • Completed design of all solid-state high-voltage power supply for gyrotron body on HL-2M ECRH. • Consist of 58 PSM modules and one BUCK module, controlled by DSP system. • Fabricated full voltage 35 kV, 200 mA BPS and tested in dummy load. • The BPS can operate in three modes: single pulse mode, multi-pulse modulation mode and the six-level preset mode. - Abstract: Gyrotron plays an important role in the research of electron cyclotron resonance heating (ECRH) on Tokomak. The high-frequency switched power supply technology and pulse step modulation (PSM) technology are used in the development of the all solid high-voltage body power supply (BPS) for 1 MW/105 GHz Gyrotron on ECRH system. Firstly, the basic structure of the BPS and its control system are introduced. Secondly, the software control algorithm of voltage stabilization and modulate method are developed. Finally, the design is verified by the experiments. The experimental results of the single pulse mode, the multi-pulse modulation mode and the six-level preset mode, are shown. The output voltage of the power supply can reach 35 kV and the current at about 200 mA, which are adjustable in the full range. The maximum modulation frequency can reach 1 kHz and the front edge of the pulse can be adjust from 0 to 3 ms and the accuracy of the output voltage is less than 100 V. The results show that the control method is feasible and can be applied to other high power microwave sources.

  14. Environmental impact of high voltage substations

    International Nuclear Information System (INIS)

    Geambasu, C.; Popadiuc, S.; Drobota, C.; Marza, F.

    2004-01-01

    The first Romanian methodology for simultaneous environmental and human risk evaluation in case of HV installations within substations pertaining to nuclear power stations, based on EU regulation is now applicable in Cernavoda substation. High voltage substations are zones where the environmental impact is focused on electromagnetic field that's causes particular effects in living tissues (human being included). That is the reason why is necessary to identify the potential risk sources, the asses including the way to correct them and to dissimulate the results to the staff and the operational personal.(author)

  15. Design philosophy and use of high voltage power systems for multi-megawatt ion beam accelerators

    International Nuclear Information System (INIS)

    Barber, G.C.; Broverman, A.Y.; Hill, R.E.; Loring, C.M.; Ponte, N.S.

    1977-01-01

    The requirements for a neutral beam high voltage power system are derived from the characteristics of the ion source. High voltage system component characteristic requirements and choices are described

  16. An approach for high voltage power supply system for HCAL of LHCb experiment

    International Nuclear Information System (INIS)

    Cimpean, A.; Dumitru, D.; Kluger, A.; Magureanu, C.; Tarta, D.; Coca, C.; Orlandea, M.; Popescu, S.

    2003-01-01

    The main aim of the calorimeter system of the LHCb (Large Hadron Collider Beauty) experiment dedicated to precision measurements of CP violation and rare phenomena is to provide identification of the electrons, hadrons and photons, for the level-0 trigger and offline analysis with measurements of position and energy. The system consists in a scintillator pad/preshower (SPD/PS) detector, an electromagnetic calorimeter (ECAL) and a hadron calorimeter (HCAL), all the sub-detectors having a similar technology with scintillating tiles as active material and being read out via wavelength-shifting fibers and with an identical readout electronics for ECAL and HCAL and similar electronics for the PS. During 1997-1999 a computer controlled High Voltage (HV) distribution scheme was developed by Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) group and used to supply the PMTs of half HCAL prototype during the beam tests (1998-2000). This scheme consisted of three parts: 1) a control box which includes low voltage power supply, the RS232 interface to a PC and three modules of high voltage power supply; 2) two types of multichannel HV distributors with an individual voltage setting; 3) a software package to control all settings and refresh them periodically. Based on the acquired experience, a new design for a High Voltage Power Supply (HVPS) which satisfies the LHCb requirements has been developed for PMTs of the hadron calorimeter. The demands of this system are simplicity and low cost. This HVPS with multiple outputs (HV for photocathode and D1 - D4 dynodes) is destined to supply, with the same high voltage, groups of PMTs sorted by similar characteristics as gain and sensitivity. Because of the high rates (∼ 40 MHz) supported by PMTs, booster voltage sources are necessary to supply current for the last 4 dynodes. The box has 5 HV power supplies for photocathodes and the last 4 dynodes, each HV power supply being followed by a 4 channel

  17. Leakage Currents in Low-Voltage PME and BME Ceramic Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    Introduction of BME capacitors to high-reliability electronics as a replacement for PME capacitors requires better understanding of changes in performance and reliability of MLCCs to set justified screening and qualification requirements. In this work, absorption and leakage currents in various lots of commercial and military grade X7R MLCCs rated to 100V and less have been measured to reveal difference in behavior of PME and BME capacitors in a wide range of voltages and temperatures. Degradation of leakage currents and failures in virgin capacitors and capacitors with introduced cracks has been studied at different voltages and temperatures during step stress highly accelerated life testing. Mechanisms of charge absorption, conduction and degradation have been discussed and a failure model in capacitors with defects suggested.

  18. Static Electricity as Part of Electromagnetic Environment on High-Voltage Electrical Substation

    Directory of Open Access Journals (Sweden)

    M. I. Fursanov

    2012-01-01

    Full Text Available Causes of occurrences electrostatic discharges (ESD on high-voltage electric substation were investigated and dependences values ESD’s on parameters interaction structures, humidity of air were found. Experimental research values ESD’s on high-voltage electric substation and in man-made conditions was fulfilled. Uncertainty measurement’s was taken into consideration by research results analyze. Matching with research of other authors was made. Danger ESD’s for electric devises was established.

  19. Measurement and statistical analysis of single-molecule current-voltage characteristics, transition voltage spectroscopy, and tunneling barrier height.

    Science.gov (United States)

    Guo, Shaoyin; Hihath, Joshua; Díez-Pérez, Ismael; Tao, Nongjian

    2011-11-30

    We report on the measurement and statistical study of thousands of current-voltage characteristics and transition voltage spectra (TVS) of single-molecule junctions with different contact geometries that are rapidly acquired using a new break junction method at room temperature. This capability allows one to obtain current-voltage, conductance voltage, and transition voltage histograms, thus adding a new dimension to the previous conductance histogram analysis at a fixed low-bias voltage for single molecules. This method confirms the low-bias conductance values of alkanedithiols and biphenyldithiol reported in literature. However, at high biases the current shows large nonlinearity and asymmetry, and TVS allows for the determination of a critically important parameter, the tunneling barrier height or energy level alignment between the molecule and the electrodes of single-molecule junctions. The energy level alignment is found to depend on the molecule and also on the contact geometry, revealing the role of contact geometry in both the contact resistance and energy level alignment of a molecular junction. Detailed statistical analysis further reveals that, despite the dependence of the energy level alignment on contact geometry, the variation in single-molecule conductance is primarily due to contact resistance rather than variations in the energy level alignment.

  20. The Design of Nanosecond Fast-switch Pulsed High Voltage Power Supply Based on Solid-state

    International Nuclear Information System (INIS)

    Chen Wenguang; Chen Wei; Rao Yihua

    2009-01-01

    The high voltage pulsed power supply is applied in the experiment of the nuclear science widely. It main consist of DC high-voltage power supply (HVPS) and pulse modulator. The high-frequency series-resonant inverter technology and IGBT series technology are used to design the HVPS and the modulator, respectively. The main circuit, control circuit, high voltage transformer and solid-state switch are illuminated in the paper. The apparatus can operate at a maximum output voltage of 6 kilovolt, which can be modulated single pulse and also be modulated by series pulse. A prototype is fabricated and tested, experimental results show that the pulsed power supply is well-designed and rising edge time to meet the nsclass; it can achieve the requirement of rapid modulation. (authors)

  1. Stability of high current diode under 100-nanosecond-pulse voltage

    International Nuclear Information System (INIS)

    Lai Dingguo; Qiu Aici; Zhang Yongmin; Huang Jianjun; Ren Shuqing; Yang Li

    2012-01-01

    Stability of high current diode under pulse voltage with 80 ns and 34 ns rise time was studied on the flash Ⅱ accelerator. Influence of rise time of diode voltage on startup time and cathode emission uniformity and repeatability of diode impedance was analyzed by comparing the experimental results with numerically simulated results, and the influence mechanism was discussed. The startup time of diode increases with the increasing of rise time of voltage, and the repeatability of diode impedance decreases. Discal plane cathode is prone to emit rays intensely in the center area, the time that plasma covers the surface of the cathode increases and the shielding effect has more impact on cathode emission according to the increase of rise time. Local intense emission on the cathode increases expansion speed of plasma and reduces the effective emission area. The stability of characteristic impedance of diode under a pulse voltage with slow rise time is decreased by the combined action of expansion speed of plasma and the effective emission area. (authors)

  2. Analysis of temperature-dependant current–voltage characteristics and extraction of series resistance in Pd/ZnO Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Mayimele, M A, E-mail: meehleketo@gmail.com; Rensburg, J P van. Janse; Auret, F D; Diale, M

    2016-01-01

    We report on the analysis of current voltage (I–V) measurements performed on Pd/ZnO Schottky barrier diodes (SBDs) in the 80–320 K temperature range. Assuming thermionic emission (TE) theory, the forward bias I–V characteristics were analysed to extract Pd/ZnO Schottky diode parameters. Comparing Cheung’s method in the extraction of the series resistance with Ohm’s law, it was observed that at lower temperatures (T<180 K) the series resistance decreased with increasing temperature, the absolute minimum was reached near 180 K and increases linearly with temperature at high temperatures (T>200 K). The barrier height and the ideality factor decreased and increased, respectively, with decrease in temperature, attributed to the existence of barrier height inhomogeneity. Such inhomogeneity was explained based on TE with the assumption of Gaussian distribution of barrier heights with a mean barrier height of 0.99 eV and a standard deviation of 0.02 eV. A mean barrier height of 0.11 eV and Richardson constant value of 37 A cm{sup −2} K{sup −2} were determined from the modified Richardson plot that considers the Gaussian distribution of barrier heights.

  3. Room to high temperature measurements of flexible SOI FinFETs with sub-20-nm fins

    KAUST Repository

    Diab, Amer El Hajj

    2014-12-01

    We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of temperature variation on drain current, gate leakage current, and transconductance. Variation of extracted parameters, such as low-field mobility, subthreshold swing, threshold voltage, and ON-OFF current characteristics, is reported too. Direct comparison is made to a rigid version of the SOI FinFETs. The mobility degradation with temperature is mainly caused by phonon scattering mechanism. The overall excellent devices performance at high temperature after release is outlined proving the suitability of truly high-performance flexible inorganic electronics with such advanced architecture.

  4. A new method for analyzing and design of guard electrodes of high voltage insulators chain

    International Nuclear Information System (INIS)

    Vahidi, B.; Mohammad Zadeh, A.

    2002-01-01

    The main aim of this paper is analyzing design of guard electrodes of high voltage insulators chain. These electrodes are used for making the distribution of uniform potential across the insulators chain, reducing leakage current and preventing the degradation of insulators. If the design is not correct or in the case of insulators chain without guard electrodes, the potential distribution will not uniform. Thus the voltage drops on the insulators adjacent to conductors will be more than maximum voltage that can be tolerated by the insulators. Therefore these voltage drops can damage the insulators. In this paper A new method is introduced for analyzing and design of ga urad electrodes of high voltage insulators chain

  5. Commissioning experiences on high voltage generator of 750 KeV DC accelerator at RRCAT, Indore

    International Nuclear Information System (INIS)

    Banwari, R.; Kasliwal, A.; Pandit, T.G.

    2009-01-01

    Design approach of high voltage generator for 750 keV DC accelerator, developed at RRCAT Indore, inculcates a unique feature of high frequency operation of symmetrical Cockcroft-Walton voltage generator. Apart from design simplicity and feasibility of modular construction, the high frequency use of symmetrical Cockcroft-Walton circuit gives added advantages of less ripple, better regulation, faster response and low stored energy in the system. Additionally the scheme allows us the use of low voltage, light weight components thus improving the overall economy of the system. The accelerator has been commissioned and made operational at its rated energy of 750 keV in the recent past. With brief introduction on design aspects of high voltage generator and filament power supply of this accelerator, the paper presented here describes the developmental steps of various components with focus on challenges encountered and solutions implemented. Development of high frequency inverter, high voltage ferrite core transformer, compensating inductors, interface bushings, voltage multiplier stack, and filament transformer along with floating power supply for electron emitter of the accelerator has been dealt in detail. The failures encountered during commissioning stages of the accelerator have been reported with measures taken for improvement of the specific components. Intricacies of the reflected capacitance of the multiplier stack and arc-current ground return are also described with their effects on system operation and reliability. (author)

  6. The system of high-voltage power PMT for experiments at the JINR Nuclotron

    International Nuclear Information System (INIS)

    Piyadin, S.M.; Ladygin, V.P.; Pilyar, A.V.; Reznikov, S.G.; Janek, M.

    2015-01-01

    An 8-channel high-voltage power system based on the use of the module «Wenzel Elektronik N1130» is described. Specifications of control modules 8DAC-12 and 8ADC-14 designed for the high-voltage systems in CAMAC standard are presented. This system is designed to provide the power for the detectors used in physics experiments at the JINR Nuclotron.

  7. In-situ observation of the alpha/beta cristobalite transition using high voltage electron microscopy

    International Nuclear Information System (INIS)

    Meike, A.; Glassley, W.E.

    1990-01-01

    A high temperature water vapor phase is expected to persist in the vicinity of high level radioactive waste packages for several hundreds of years. The authors have begun an investigation of the structural and chemical effects of water on cristobalite because of its abundance in the near field environment. A high voltage transmission electron microscope (HVEM) investigation of bulk synthesized α-cristobalite to be used in single phase dissolution and precipitation kinetics experiments revealed the presence β-cristobalite, quartz and amorphous silica, in addition to α-cristobalite. Consequently, this apparent metastable persistence of β-cristobalite and amorphous silica during the synthesis of α-cristobalite was investigated using a heating stage and an environmental cell installed in the HVEM that allowed the introduction of either dry CO 2 or a CO 2 + H 2 O vapor. Preliminary electron diffraction evidence suggests that the presence of water vapor affected the α-β transition temperature. Water vapor may also be responsible for the development of an amorphous silica phase at the transition that may persist over an interval of several tens of degrees. The amorphous phase was not documented during the dry heating experiments

  8. In-situ observation of the alpha/beta cristobalite transition using high voltage electron microscopy

    International Nuclear Information System (INIS)

    Meike, A.; Glassley, W.

    1989-10-01

    A high temperature water vapor phase is expected to persist in the vicinity of high level radioactive waste packages for several hundreds of years. The authors have begun an investigation of the structural and chemical effects of water on cristobalite because of its abundance in the near field environment. A high voltage transmission electron microscope (HVEM) investigation of bulk synthesized α-cristobalite to be used in single phase dissolution and precipitation kinetics experiments revealed the presence β-cristobalite, quartz and amorphous silica, in addition to α-cristobalite. Consequently, this apparent metastable persistence of β-cristobalite and amorphous silica during the synthesis of α-cristobalite was investigated using a heating stage and an environmental cell installed in the HVEM that allowed the introduction of either dry CO 2 or a CO 2 + H 2 O vapor. Preliminary electron diffraction evidence suggests that the presence of water vapor affected the α-β transition temperature. Water vapor may also be responsible for the development of an amorphous silica phase at the transition that may persist over an interval of several tens of degrees. The amorphous phase was not documented during the dry heating experiments. 20 refs., 7 figs., 5 tabs

  9. Technical and economic aspects of the transmission of energy at extra high voltages

    Energy Technology Data Exchange (ETDEWEB)

    Kahnt, R

    1967-01-01

    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. A treatment of the technical and economic problems arising in three phase extra high voltage transmission is presented. These include selection of voltage, economical design of power lines, insulation problems, power supply dependability, equipment rating and reactive power and stability problems.

  10. Adventitious X-radiation from high voltage equipment

    International Nuclear Information System (INIS)

    Martin, E.B.M.

    1979-01-01

    The monograph is concerned with hazards of unwanted x-rays from sources such as television receivers, high voltage equipment, radar transmitters, switchgear and electron beam apparatus for welding, evaporation, analysis and microscopy. Chapters are included on units, production of x radiation, biological effects, protection standards, radiation monitoring, shielding and control of access, medical and dosimetric supervision and types of equipment. A bibliography of 92 references and other cited literature is included. (U.K.)

  11. High voltage fast switches for nuclear applications

    International Nuclear Information System (INIS)

    Chatroux, D.; Lausenaz, Y.; Villard, J.F.; Lafore, D.

    1999-01-01

    SILVA process consists in a selective ionization of the 235 uranium isotope, using laser beams generated by dye lasers pumped by copper vapour laser (C.V.L.). SILVA involves power electronic for 3 power supplies: - copper vapour laser power supply, - extraction power supply to generate the electric field in the vapour, and - electron beam power supply for vapour generation. This article reviews the main switches that are proposed on the market or are on development and that could be used in SILVA power supplies. The SILVA technical requirements are: high power, high voltage and very short pulses (200 ns width). (A.C.)

  12. Supplementary High-Input Impedance Voltage-Mode Universal Biquadratic Filter Using DVCCs

    Directory of Open Access Journals (Sweden)

    Jitendra Mohan

    2012-01-01

    Full Text Available To further extend the existing knowledge on voltage-mode universal biquadratic filter, in this paper, a new biquadratic filter circuit with single input and multiple outputs is proposed, employing three differential voltage current conveyors (DVCCs, three resistors, and two grounded capacitors. The proposed circuit realizes all the standard filter functions, that is, high-pass, band-pass, low-pass, notch, and all-pass filters simultaneously. The circuit enjoys the feature of high-input impedance, orthogonal control of resonance angular frequency (o, and quality factor (Q via grounded resistor and the use of grounded capacitors which is ideal for IC implementation.

  13. Stress relief of ceramic components in high voltage assemblies. Final report

    International Nuclear Information System (INIS)

    Heinen, R.J.

    1979-02-01

    Two types of ceramic packages were evaluated to determine the effectiveness of encapsulating the ceramic components in beta eucryptite filled epoxy. The requirements (no high voltage breakdown, no ceramic cracking, and no encapsulant cracking) were met by the spark gap assembly, but the sprytron assembly had cracking in the encapsulant after thermal cycling. The encapsulation of the ceramic component in beta eucryptite filled epoxy with a stress decoupling material selectively applied in the stress concentrated areas were used to prevent cracking in the sprytron encapsulant. This method is proposed as the standard encapsulation process for high voltage ceramic components

  14. Universal trench design method for a high-voltage SOI trench LDMOS

    Institute of Scientific and Technical Information of China (English)

    Hu Xiarong; Zhang Bo; Luo Xiaorong; Li Zhaoji

    2012-01-01

    The design method for a high-voltage SOl trench LDMOS for various trench permittivities,widths and depths is introduced.A universal method for efficient design is presented for the first time,taking the trade-off between breakdown voltage (BV) and specific on-resistance (Rs,on) into account.The high-k (relative permittivity)dielectric is suitable to fill a shallow and wide trench while the low-k dielectric is suitable to fill a deep and narrow trench.An SOI LDMOS with a vacuum trench in the drift region is also discussed.Simulation results show that the high FOM BV2/Rs,on can be achieved with a trench filled with the low-k dielectric due to its shortened cell-pitch.

  15. High Input Voltage Discharge Supply for High Power Hall Thrusters Using Silicon Carbide Devices

    Science.gov (United States)

    Pinero, Luis R.; Scheidegger, Robert J.; Aulsio, Michael V.; Birchenough, Arthur G.

    2014-01-01

    A power processing unit for a 15 kW Hall thruster is under development at NASA Glenn Research Center. The unit produces up to 400 VDC with two parallel 7.5 kW discharge modules that operate from a 300 VDC nominal input voltage. Silicon carbide MOSFETs and diodes were used in this design because they were the best choice to handle the high voltage stress while delivering high efficiency and low specific mass. Efficiencies in excess of 97 percent were demonstrated during integration testing with the NASA-300M 20 kW Hall thruster. Electromagnet, cathode keeper, and heater supplies were also developed and will be integrated with the discharge supply into a vacuum-rated brassboard power processing unit with full flight functionality. This design could be evolved into a flight unit for future missions that requires high power electric propulsion.

  16. A real time measurement of junction temperature variation in high power IGBT modules for wind power converter application

    DEFF Research Database (Denmark)

    Ghimire, Pramod; Pedersen, Kristian Bonderup; de Vega, Angel Ruiz

    2014-01-01

    This paper presents a real time measurement of on-state forward voltage and estimating the junction temperature for a high power IGBT module during a power converter operation. The power converter is realized as it can be used for a wind turbine system. The peak of the junction temperature is dec...

  17. 30 CFR 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.

    Science.gov (United States)

    2010-07-01

    ... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.802 Protection... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of high-voltage circuits; neutral... grounded through a suitable resistor at the source transformers, and a grounding circuit, originating at...

  18. DEMONSTRATION BULLETIN: HIGH VOLTAGE ELECTRON BEAM TECHNOLOGY - HIGH VOLTAGE ENVIRONMENTAL APPLICATIONS, INC.

    Science.gov (United States)

    The high energy electron beam irradiation technology is a low temperature method for destroying complex mixtures of hazardous organic chemicals in solutions containing solids. The system consists of a computer-automated, portable electron beam accelerator and a delivery system. T...

  19. High voltage load resistor array

    Science.gov (United States)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  20. Voltage current characteristics of type III superconductors

    International Nuclear Information System (INIS)

    Dorofejev, G.L.; Imenitov, A.B.; Klimenko, E.Y.

    1980-01-01

    An adequate description of voltage-current characteristics is important in order to understand the nature of high critical current for the electrodynamic construction of type-III superconductors and for commercial superconductor specification. Homogeneous monofilament and multifilament Nb-Ti, Nb-Zr,Nb 3 Sn wires were investigated in different ranges of magnetic field, temperature and current. The shape of the voltage-current characteristics of multifilament wires, and the parameter's dependence on temperature and magnetic field may be explained qualitatively by the longitudinal heterogeneous nature of the filaments. A method of attaining the complete specification of the wire's electro-physical properties is proposed. It includes the traditional description of a critical surface (i.e. the surface corresponding to a certain conventional effective resistivity in T,B,J-space) and a description of any increasing parameter that depends on B and T. (author)

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