A new linear induction voltage adder approach to radiography
Mazarakis, M.G.; Poukey, J.W.; Frost, C.A.; Johnson, D.L.; Shope, S.L.; Halbleib, J.A.; Prestwich, K.R.; Turman, B.N.; Smith, I.
1992-01-01
At present, two types of accelerators are being utilized for x-ray radiography: first a linear RF or induction accelerator with multiple accelerating gaps and beam vacuum magnetic transport systems; and second, single gap pulse-power devices with a high voltage Blumlein pulse forming line. The authors present a conceptual design of a new type of linear induction accelerator that can bridge the gap between the two devices. It can produce 30--50-kA electron currents small diameter (∼ 1 mm) and high energy (12--20-MV) beams. There is no beam drifting through the device. The voltage addition of the accelerating gaps occurs at the central self-magnetically insulated cathode electrode. The electron beam is created at the high voltage end in a single gap diode. A magnetically-immersed foilless diode can produce high quality 0.5 mm radius 30--50 kA beams. A short 100--200-kG small bore solenoidal coil is required to maintain the beam radius during transport from the cathode tips to the x-ray converter target, 50--70 cm downstream. The idea of very high impedance MITL voltage adder accelerators was first tested with RADLAC II/SMILE experiments where 12--14-MV, 50-kA 1 cm radius beams were produced with 2--3 mm annulus thickness. A 12.5 m eight-stage voltage adder was utilized, coupled to a 20 kG magnetically immersed foilless diode. In addition the magnetically-immersed foilless diodes with very thin (mm diameter) cathode tips were investigated in experiments with the IBEX accelerator. As an example of this new accelerator technology the authors present the following point design for a 16-MV, 50-kA accelerator producing 1-mm diameter electron beams. The design is based on a cavity fed MITL voltage adder which performs the series addition of the voltage pulses from 16 identical inductively-isolated cavity feed systems. Each cavity is a structure that is driven by one 14 ohm pulse-forming line, providing a 1 MV voltage pulse to the accelerating gap
Linear inductive voltage adders (IVA) for advanced hydrodynamic radiography
Mazarakis, M.G.; Boyes, J.D.; Johnson, D.L.
1998-01-01
The electron beam which drifts through the multiple cavities of conventional induction linacs (LIA) is replaced in an IVA by a cylindrical metal conductor which extends along the entire length of the device and effectuates the addition of the accelerator cavity voltages. In the approach to radiography, the linear inductive voltage adder drives a magnetically immersed electron diode with a millimeter diameter cathode electrode and a planar anode/bremsstrahlung converter. Both anode and cathode electrodes are immersed in a strong (15--50 T) solenoidal magnetic field. The electron beam cross section is approximately of the same size as the cathode needle and generates a similar size, very intense x-ray beam when it strikes the anode converter. An IVA driven diode can produce electron beams of equal size and energy as a LIA but with much higher currents (40--50 kA versus 4--5 kA), simpler hardware and thus lower cost. The authors present here first experimental validations of the technology utilizing HERMES 3 and SABRE IVA accelerators. The electron beam voltage and current were respectively of the order of 10 MV and 40 kA. X-ray doses of up to 1 kR at sign 1 m and spot sizes as small as 1.7 mm (at 200 R doses) were measured
Voltage-regulating constant-current sources in a linear induction accelerator
Zhao Juan; Cao Kefeng; Deng Jianjun; Zhu Lijun; Yang Jia; Ye Chao; Huang Bin; Cao Ningxiang; Dong Jinxuan; Zhang Jichang; Yu Zhiguo; Chen Min
2002-01-01
Constant-current Sources are one of key units in a linear induction accelerator. The requirements for the sources are to supply stable direct current of high power for the induction coil, be easy to computer-control and highly stable and reliable. Applying the technique of linear current source regulating in series, the primary voltage of the power transformer is regulated through an MJYS-JL-350A type three-phase alterative voltage-regulating module. The output current variation is 300-500 A when the load variation is 0.06-0.1 Ω and the voltage drop of the regulator tube is controlled within 8 V±2V when the variation of mains voltage is in ±10%. Both the current ripple and stability meet the technical requirements. The constant-current sources are controlled through an industrial controller. For each of the constant-current sources has a smallest system comprised of 8051 which is communication-controlled through a RS-485 interface, the sources can be controlled remotely
Air-gap field, induced voltage and thrust in the short-stator linear induction motor
Deleroi, W
1980-07-15
The description of the magnetic field in the air-gap of a short-primary linear induction motor, and the subsequent calculation of the thrust developed and the voltages induced in the stator bars can be made by using balancing waves. These balancing waves are generated at any point where the field wave that would exist in a machine of infinite length is disturbed. In the linear motor these disturbances occur at the ends of the stator iron and at discontinuities in the distribution of the stator winding, which exist in machines having stepped windings. From the points where they are generated, free balancing waves travel in two directions and determine the performance of these machines to a large extent. The voltage they induce in a stator bar can be determined from the core flux and mapped on a phasor diagram. The resulting voltage phasor follows a logarithmic spiral. The resulting voltages induced in the three phase windings form a strongly asymmetrical system which can be split-up into positive-, negative- and zerosequence components depending on the slip. The tangential forces may be calculated as the product of the magnetic flux density in the air-gap and the linear current density in either the stator or the reaction rail. As the 'magnetic tail' outside the machine also gives rise to forces in the direction of motion, both methods yield quite different force distributions, though for the resulting force the same value is found.
A new linear inductive voltage adder driver for the Saturn Accelerator
Mazarakis, M.G.; Spielman, R.B.; Struve, K.W.; Long, F.W.
2000-01-01
Saturn is a dual-purpose accelerator. It can be operated as a large-area flash x-ray source for simulation testing or as a Z-pinch driver especially for K-line x-ray production. In the first mode, the accelerator is fitted with three concentric-ring 2-MV electron diodes, while in the Z-pinch mode the current of all the modules is combined via a post-hole convolute arrangement and driven through a cylindrical array of very fine wires. We present here a point design for a new Saturn class driver based on a number of linear inductive voltage adders connected in parallel. A technology recently implemented at the Institute of High Current Electronics in Tomsk (Russia) is being utilized. In the present design we eliminate Marx generators and pulse-forming networks. Each inductive voltage adder cavity is directly fed by a number of fast 100-kV small-size capacitors arranged in a circular array around each accelerating gap. The number of capacitors connected in parallel to each cavity defines the total maximum current. By selecting low inductance switches, voltage pulses as short as 30-50-ns FWHM can be directly achieved. The voltage of each stage is low (100-200 kv). Many stages are required to achieve multi-megavolt accelerator output. However, since the length of each stage is very short (4-10 cm), accelerating gradients of higher than 1 MV/m can easily be obtained. The proposed new driver will be capable of delivering pulses of 15-MA, 36-TW, 1.2-MJ to the diode load, with a peak voltage of -2.2 MV and FWHM of 40-ns. And although its performance will exceed the presently utilized driver, its size and cost could be much smaller (approximately1/3). In addition, no liquid dielectrics like oil or deionized water will be required. Even elimination of ferromagnetic material (by using air-core cavities) is a possibility
Buttram, M.T.; Ginn, J.W.
1988-06-21
A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.
Prasenjit D. Wakode
2016-07-01
Full Text Available This paper presents the complete analysis of Linear Induction Motor (LIM under VVVF. The complete variation of LIM air gap flux under ‘blocked Linor’ condition and starting force is analyzed and presented when LIM is given VVVF supply. The analysis of this data is important in further understanding of the equivalent circuit parameters of LIM and to study the magnetic circuit of LIM. The variation of these parameters is important to know the LIM response at different frequencies. The simulation and application of different control strategies such as vector control thus becomes quite easy to apply and understand motor’s response under such strategy of control.
Bykov, Yu. A.; Krastelev, E. G., E-mail: ekrastelev@yandex.ru; Popov, G. V.; Sedin, A. A.; Feduschak, V. F. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
2016-12-15
A pulsed power source with voltage amplitude up to 800 kV for fast charging (350–400 ns) of the forming line of a high-current nanosecond accelerator is developed. The source includes capacitive energy storage and a linear pulse transformer. The linear transformer consists of a set of 20 inductors with circular ferromagnetic cores surrounded by primary windings inside of which a common stock adder of voltage with film-glycerol insulation is placed. The primary energy storage consists of ten modules, each of which is a low-inductance assembly of two capacitors with a capacitance of 0.35 μF and one gas switch mounted in the same frame. The total energy stored in capacitors is 5.5 kJ at the operating voltage of 40 kV. According to test results, the parameters of the equivalent circuit of the source are the following: shock capacitance = 17.5 nF, inductance = 2 μH, resistance = 3.2 Ω.
Briggs, R.J.
1986-06-01
The development of linear induction accelerators has been motivated by applications requiring high-pulsed currents of charged particles at voltages exceeding the capability of single-stage, diode-type accelerators and at currents too high for rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multi-stage induction machine, but the 50-MeV, 10-kA Advanced Test Accelerator (ATA) at LLNL is the highest voltage machine in existence at this time. The advent of magnetic pulse power systems makes sustained operation at high-repetition rates practical, and this capability for high-average power is very likely to open up many new applications of induction machines in the future. This paper surveys the US induction linac technology with primary emphasis on electron machines. A simplified description of how induction machines couple energy to the electron beam is given, to illustrate many of the general issues that bound the design space of induction linacs
Elliott, D. G.
1977-01-01
Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.
Barkman, W.E.; Adams, W.Q.; Berrier, B.R.
1978-01-01
A linear induction motor has been operated on a test bed with a feedback pulse resolution of 5 nm (0.2 μin). Slewing tests with this slide drive have shown positioning errors less than or equal to 33 nm (1.3 μin) at feedrates between 0 and 25.4 mm/min (0-1 ipm). A 0.86-m (34-in)-stroke linear motor is being investigated, using the SPACO machine as a test bed. Initial results were encouraging, and work is continuing to optimize the servosystem compensation
Voltage linear transformation circuit design
Sanchez, Lucas R. W.; Jin, Moon-Seob; Scott, R. Phillip; Luder, Ryan J.; Hart, Michael
2017-09-01
Many engineering projects require automated control of analog voltages over a specified range. We have developed a computer interface comprising custom hardware and MATLAB code to provide real-time control of a Thorlabs adaptive optics (AO) kit. The hardware interface includes an op amp cascade to linearly shift and scale a voltage range. With easy modifications, any linear transformation can be accommodated. In AO applications, the design is suitable to drive a range of different types of deformable and fast steering mirrors (FSM's). Our original motivation and application was to control an Optics in Motion (OIM) FSM which requires the customer to devise a unique interface to supply voltages to the mirror controller to set the mirror's angular deflection. The FSM is in an optical servo loop with a wave front sensor (WFS), which controls the dynamic behavior of the mirror's deflection. The code acquires wavefront data from the WFS and fits a plane, which is subsequently converted into its corresponding angular deflection. The FSM provides +/-3° optical angular deflection for a +/-10 V voltage swing. Voltages are applied to the mirror via a National Instruments digital-to-analog converter (DAC) followed by an op amp cascade circuit. This system has been integrated into our Thorlabs AO testbed which currently runs at 11 Hz, but with planned software upgrades, the system update rate is expected to improve to 500 Hz. To show that the FSM subsystem is ready for this speed, we conducted two different PID tuning runs at different step commands. Once 500 Hz is achieved, we plan to make the code and method for our interface solution freely available to the community.
Induction sensor for measuring the accelerating voltage in an iron-free induction accelerator
Bol'nykh, N.S.; Il'in, Yu.M.; Kostyushok, A.A.; Suvorov, V.A.
1987-01-01
An inductive sensor is described for measuring the amplitude and form of the accelerating-voltage pulse in the storage coils in a radial iron-free linear induction accelerator. The sensor does not respond to interference from external fields and does not require adjustment after calibration
Inductive voltage adder (IVA) for submillimeter radius electron beam
Mazarakis, M.G.; Poukey, J.W.; Maenchen, J.E.
1996-01-01
The authors have already demonstrated the utility of inductive voltage adder accelerators for production of small-size electron beams. In this approach, the inductive voltage adder drives a magnetically immersed foilless diode to produce high-energy (10--20 MeV), high-brightness pencil electron beams. This concept was first demonstrated with the successful experiments which converted the linear induction accelerator RADLAC II into an IVA fitted with a small 1-cm radius cathode magnetically immersed foilless diode (RADLAC II/SMILE). They present here first validations of extending this idea to mm-scale electron beams using the SABRE and HERMES-III inductive voltage adders as test beds. The SABRE experiments are already completed and have produced 30-kA, 9-MeV electron beams with envelope diameter of 1.5-mm FWHM. The HERMES-III experiments are currently underway
Segmented rail linear induction motor
Cowan, Jr., Maynard; Marder, Barry M.
1996-01-01
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.
Inductive voltage compensation in superconducting magnet systems
Yeh, H.T.; Goddard, J.S.; Shen, S.S.
1979-01-01
This paper details several techniques of inductive voltage compensation developed for quench detection in superconducting magnet systems with multiple coils and power supplies, with particular application for the Large Coil Test Facility (LCTF). Sources of noise, their magnitudes, and the sensitivity required for normal zone detection to avoid damage to the magnets are discussed. Two passive compensation schemes (second difference and central difference) are introduced and illustrated by parameters of LCTF; these take advantage of coil symmetries and other system characteristics. An active compensation scheme based on current rate input fom pickup coils and utilizing theory on ac loss voltage for calibration was tested, and the experimental setup and test results are discussed
Dragon-I Linear Induction Electron Accelerator
Ding Bonan; Deng Jianjun; Wang Huacen; Cheng Nian'an; Dai Guangsen; Zhang Linwen; Liu Chengjun; Zhang Wenwei; Li Jin; Zhang Kaizhi
2005-01-01
Dragon-I is a linear induction electron accelerator. This facility consists of a 3.6 MeV injector, 38 meter beam transport line and 16 MeV induction accelerator powered by high voltage generators, including 8 Marx generators and 48 Blumlein lines. This paper describes the physics design, development and experimental results of Dragon-I. The key technology is analyzed in the accelerator development, and the design requirements and operation of the major subsystems are presented. The experimental results show Dragon-I generates an 18-20 MeV, 2.5 kA, 70 ns electron beam. The X-ray spot size is about 1.2 mm and dose level about 0.103 C/kg at 1 meter. (authors)
Cell design for the DARHT linear induction accelerators
Burns, M.; Allison, P.; Earley, L.; Liska, D.; Mockler, C.; Ruhe, J.; Tucker, H.; Walling, L.
1991-01-01
The Dual-Axis Radiographic Hydrotest (DARHT) facility will employ two linear induction accelerators to produce intense, bremsstrahlung x- ray pulses for flash radiography. The accelerator cell design for a 3- kA, 16--20 MeV, 60-ns flattop, high-brightness electron beam is presented. The cell is optimized for high-voltage stand-off while also minimizing the its transverse impedance. Measurements of high- voltage and rf characteristics are summarized. 7 refs., 5 figs
Linear induction accelerator and pulse forming networks therefor
Buttram, Malcolm T.; Ginn, Jerry W.
1989-01-01
A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.
Excitation of voltage oscillations in an induction voltage adder
Nichelle Bruner
2009-07-01
Full Text Available The induction voltage adder is an accelerator architecture used in recent designs of pulsed-power driven x-ray radiographic systems such as Sandia National Laboratories’ Radiographic Integrated Test Stand (RITS, the Atomic Weapons Establishment’s planned Hydrus Facility, and the Naval Research Laboratory’s Mercury. Each of these designs relies on magnetic insulation to prevent electron loss across the anode-cathode gap in the vicinity of the adder as well as in the coaxial transmission line. Particle-in-cell simulations of the RITS adder and transmission line show that, as magnetic insulation is being established during a pulse, some electron loss occurs across the gap. Sufficient delay in the cavity pulse timings provides an opportunity for high-momentum electrons to deeply penetrate the cavities of the adder cells where they can excite radio-frequency resonances. These oscillations may be amplified in subsequent gaps, resulting in oscillations in the output power. The specific modes supported by the RITS-6 accelerator and details of the mechanism by which they are excited are presented in this paper.
Reproducible and controllable induction voltage adder for scaled beam experiments
Sakai, Yasuo; Nakajima, Mitsuo; Horioka, Kazuhiko [Department of Energy Sciences, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)
2016-08-15
A reproducible and controllable induction adder was developed using solid-state switching devices and Finemet cores for scaled beam compression experiments. A gate controlled MOSFET circuit was developed for the controllable voltage driver. The MOSFET circuit drove the induction adder at low magnetization levels of the cores which enabled us to form reproducible modulation voltages with jitter less than 0.3 ns. Preliminary beam compression experiments indicated that the induction adder can improve the reproducibility of modulation voltages and advance the beam physics experiments.
Gower, E J; Sullivan, J S
2002-01-01
High voltage, solid state, inductive adder, pulse generators have found increasing application as fast kicker pulse modulators for charged particle beams. The solid state, inductive adder, pulse generator is similar in operation to the linear induction accelerator. The main difference is that the solid state, adder couples energy by transformer action from multiple primaries to a voltage summing stalk, instead of an electron beam. Ideally, the inductive adder produces a rectangular voltage pulse at the load. In reality, there is usually some voltage variation at the load due to droop on primary circuit storage capacitors, or, temporal variations in the load impedance. Power MOSFET circuits have been developed to provide analog modulation of the output voltage amplitude of a solid state, inductive adder, pulse generator. The modulation is achieved by including MOSFET based, variable subtraction circuits in the multiple primary stack. The subtraction circuits can be used to compensate for voltage droop, or, to tailor the output pulse amplitude to provide a desired effect in the load. Power MOSFET subtraction circuits have been developed to modulate short, temporal (60-400 ns), voltage and current pulses. MOSFET devices have been tested up to 20 amps and 800 Volts with a band pass of 50 MHz. An analog modulation cell has been tested in a five cell high, voltage adder stack
Linear Parameter Varying Control of Induction Motors
Trangbæk, Klaus
The subject of this thesis is the development of linear parameter varying (LPV) controllers and observers for control of induction motors. The induction motor is one of the most common machines in industrial applications. Being a highly nonlinear system, it poses challenging control problems...... for high performance applications. This thesis demonstrates how LPV control theory provides a systematic way to achieve good performance for these problems. The main contributions of this thesis are the application of the LPV control theory to induction motor control as well as various contributions...
Precise derating of three phase induction motors with unbalanced voltages
Faiz, Jawad; Ebrahimpour, H.
2007-01-01
Performance analysis of three phase induction motors under supply voltage unbalance conditions is normally conducted using the well-known symmetrical components analysis. In this analysis, the voltage unbalance level at the terminals of the machine is assessed by means of the NEMA or IEC definitions. Both definitions lead to a relatively large error in predicting the performance of a machine. A method has recently been proposed in which, in addition to the voltage unbalance factor (VUF), the phase angle has been taken into account in the analysis. This means that the voltage unbalance factor is regarded as a complex value. This paper shows that although the use of the complex VUF reduces the computational error considerably, it is still high. This is proven by evaluating the derating factor of a three phase induction motor. A method is introduced to determine the derating factor precisely using the complex unbalance factor for an induction motor operating under any unbalanced supply condition. A practical case for derating of a typical three phase squirrel cage induction motor supplied by an unbalanced voltage is studied in the paper
Experimental research of double-pulse linear induction electron accelerator
Liao Shuqing; Cheng Cheng; Zheng Shuxin; Tang Chuanxiang; Lin Yuzheng; Jing Xiaobing; Mu Fan; Pan Haifeng
2009-01-01
The Mini-LIA is a double-pulse linear induction electron accelerator with megahertz repetition rates, which consists of a double-pulse power system, a thermal cathode electron gun, two induction cells, beam transportation systems and diagnosis systems, etc. Experiments of the Mini-LIA have been conducted. The double-pulse high voltage was obtained with several hundred nanosecond pulse intervals (i. e. megahertz repetition rate) and each pulse had an 80 kV amplitude with a FWHM of 80 ns. In the gap of the induction cell, the double-pulse accelerating electric field was measured via E-field probes, and the double-pulse electron beam with a current about 1.1 A has been obtained at the Mini-LIA exit. These experimental results show that the double-pulse high voltage with megahertz repetition rates can be generated by an insulation and junction system. And they also indicate that the induction cell with metglas as the ferromagnetic material and the LaB 6 thermal cathode electron gun suit the double-pulse operation with megahertz repetition rates. (authors)
Linear induction accelerator for heavy ions
Keefe, D.
1976-01-01
There is considerable recent interest in the use of high energy heavy ions to irradiate deuterium-tritium pellets in a reactor vessel to constitute a power source at the level of 1 GW or more. Various accelerator configurations involving storage rings have been suggested. This paper discusses how the technology of linear induction accelerators - well known to be matched to high current and short pulse length - may offer significant advantages for this application. (author)
В.Т. Чемерис
2006-04-01
Full Text Available There is a method of simplified calculation and design parameters choice elaborated in this article with corresponding basing for the induction system of electron-beam sterilizer on the base of linear induction accelerator taking into account the parameters of magnetic material for production of cores and parameters of pulsed voltage.
Analysis of the linear induction motor in transient operation
Gentile, G; Rotondale, N; Scarano, M
1987-05-01
The paper deals with the analysis of a bilateral linear induction motor in transient operation. We have considered an impressed voltage one-dimensional model which takes into account end effects. The real winding distribution of the armature has been represented as a lumped parameters system. By using the space vectors methodology, the partial differential equation of the sheet is solved bythe variable separation method. Therefore it's possible to arrange a system of ordinary differential equations where the unknown quantities are the space vectors of the air-gap flux density and sheet currents. Finally, we have analyzed the characteristic quantities for a no-load starting of small power motors.
Doubly-Fed Induction Generator Control Under Voltage Sags
Teodorescu, Remus; Blaabjerg, Frede; Lima, K.
2008-01-01
This paper proposes a new control technique to improve the fault-ride through capability of doubly fed induction generators (DFIG). In such generators the appearance of severe voltage sags at the coupling point make rise to high over currents at the rotor/stator windings, something that makes...
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)
Stabilization of Voltage Parameters of Induction Generator Excited by a Voltage Inverter
Padalko D.A.
2017-12-01
Full Text Available The article reveals the operational aspects of induction generator. Methods for stabilization of induction generator (IG parameters under inverter excitation are investigated. The study was carried out using mathematical description and simulation modeling in MATLAB Simulink. The paper provides analysis of causes of generated voltage amplitude and frequency displacement when the loading condition and the rate vary. Due to the parametric resonance nature of IG self-excitation, the author introduces the expression that allows estimating the capacitor capacitance required to maintain the generation process, depending on the rotor speed of electric machine, load nature and rate. Based on the studies, it was proved that it is possible to stabilize the IG voltage parameters by maintaining the magnetizing circuit inductance Lm at the constant level., and realizing a control law close to U/f = const. The study proves that using the inverter together with the voltage regulator allows ensuring the quality of electricity corresponding to modern standards. The necessity of problem solving of the required quality of the voltage by the harmonic component for the exciter - inverter with PWM is shown. The prospects of the power generation system based on induction machine (IM with a semiconductor frequency converter, which serves as an adjustable supplier of capacitive current for IM for autonomous objects, are substantiated. The use of semiconductor frequency converters makes it possible to provide high stability of the output voltage parameters and good speed of the mechatronic generation system with an asynchronous machine.
Linear induction accelerator for heavy ions
Keefe, D.
1976-09-01
There is considerable recent interest in the use of high energy (γ = 1.1), heavy (A greater than or equal to 100) ions to irradiate deuterium--tritium pellets in a reactor vessel to constitute a power source at the level of 1 GW or more. Various accelerator configurations involving storage rings have been suggested. A discussion is given of how the technology of Linear Induction Accelerators--well known to be matched to high current and short pulse length--may offer significant advantages for this application
High average power linear induction accelerator development
Bayless, J.R.; Adler, R.J.
1987-07-01
There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs
State reference design and saturated control of doubly-fed induction generators under voltage dips
Tilli, Andrea; Conficoni, Christian; Hashemi, Ahmad
2017-04-01
In this paper, the stator/rotor currents control problem of doubly-fed induction generator under faulty line voltage is carried out. Common grid faults cause a steep decline in the line voltage profile, commonly denoted as voltage dip. This point is critical for such kind of machines, having their stator windings directly connected to the grid. In this respect, solid methodological nonlinear control theory arguments are exploited and applied to design a novel controller, whose main goal is to improve the system behaviour during voltage dips, endowing it with low voltage ride through capability, a fundamental feature required by modern Grid Codes. The proposed solution exploits both feedforward and feedback actions. The feedforward part relies on suitable reference trajectories for the system internal dynamics, which are designed to prevent large oscillations in the rotor currents and command voltages, excited by line perturbations. The feedback part uses state measurements and is designed according to Linear Matrix Inequalities (LMI) based saturated control techniques to further reduce oscillations, while explicitly accounting for the system constraints. Numerical simulations verify the benefits of the internal dynamics trajectory planning, and the saturated state feedback action, in crucially improving the Doubly-Fed Induction Machine response under severe grid faults.
Induction-linear accelerators for food processing with ionizing radiation
Lagunas-Solar, M.C.
1985-01-01
Electron accelerators with sufficient beam power and reliability of operation will be required for applications in the large-scale radiation processing of food. Electron beams can be converted to the more penetrating bremsstrahlung radiation (X-rays), although at a great expense in useful X-ray power due to small conversion efficiencies. Recent advances in the technology of pulse-power accelerators indicates that Linear Induction Electron Accelerators (LIEA) are capable of sufficiently high-beam current and pulse repetition rate, while delivering ultra-short pulses of high voltage. The application of LIEA systems in food irradiation provides the potential for high product output and compact, modular-type systems readily adaptable to food processing facilities. (orig.)
Identification of voltage collapse point in self excited induction generator
Kalyanasundaram Rajambal
2009-10-01
Full Text Available This paper presents a direct equilibrium tracing method for identifying the voltage collapse point of a self-excitedinduction generator (SEIG without many trials. The technique solves differential and algebraic equations simultaneously toobtain the variables in a single step. The load parameter is also automatically varied during equilibrium tracing and thisreduces the computational time significantly. Comparing the simulation results obtained through conventional iterative procedure shows the effectiveness of the technique. An experimental verification on a 1.5KW induction machine validates the simulation results.
An implantable neurostimulator with an integrated high-voltage inductive power-recovery frontend
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)
Magnetohydrodynamic instability in annular linear induction pump
Araseki, Hideo; Kirillov, Igor R.; Preslitsky, Gennady V.; Ogorodnikov, Anatoly P.
2006-01-01
In the previous work, the authors showed some detailed aspects of the magnetohydrodynamic instability arising in an annular linear induction pump: the instability is accompanied with a low frequency pressure pulsation in the range of 0-10 Hz when the magnetic Reynolds number is larger than unity; the low frequency pressure pulsation is produced by the sodium vortices that come from some azimuthal non-uniformity of the applied magnetic field or of the sodium inlet velocity. In the present work, an experiment and a numerical analysis are carried out to verify the pump winding phase shift that is expected as an effective way to suppress the instability. The experimental data shows that the phase shift suppresses the instability unless the slip value is so high, but brings about a decrease of the developed pressure. The numerical results indicate that the phase shift causes a local decrease of the electromagnetic force, which results in the suppression of the instability and the decrease of the developed pressure. In addition, it is exhibited that the intensity of the double-supply-frequency pressure pulsation is in nearly the same level in the case with and without the phase shift
Thyristor voltage converter in induction electric drives with microprocessor control
Braslavsky, I.; Zuzev, A.; Shilin, S. [Electric Drive Department, Urals State Technical University, Ekaterinburg (Russian Federation)
1997-12-31
The paper consists of some results on developed pulse model of thyristor voltage converter which is one of the most mathematically complicated unit of electric drive. The model structure and model parameter calculating method are represented. The application of the model allows to analyse stability in `locally` by the linear pulse system theory methods with talking into consideration quantise processes within the converter. Such application provides the obtaining higher accurate results comparing with the non-linear system theory approximate methods. Logarithmic frequency characteristics are used to analyse converter dynamic features and they are represented too. (orig.) 4 refs.
All-Pass Filter Based Linear Voltage Controlled Quadrature Oscillator
Koushick Mathur
2017-01-01
Full Text Available A linear voltage controlled quadrature oscillator implemented from a first-order electronically tunable all-pass filter (ETAF is presented. The active element is commercially available current feedback amplifier (AD844 in conjunction with the relatively new Multiplication Mode Current Conveyor (MMCC device. Electronic tunability is obtained by the control node voltage (V of the MMCC. Effects of the device nonidealities, namely, the parasitic capacitors and the roll-off poles of the port-transfer ratios of the device, are shown to be negligible, even though the usable high-frequency ranges are constrained by these imperfections. Subsequently the filter is looped with an electronically tunable integrator (ETI to implement the quadrature oscillator (QO. Experimental responses on the voltage tunable phase of the filter and the linear-tuning law of the quadrature oscillator up to 9.9 MHz at low THD are verified by simulation and hardware tests.
Peak thrust operation of linear induction machines from parameter identification
Zhang, Z.; Eastham, T.R.; Dawson, G.E. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Electrical and Computer Engineering
1995-12-31
Various control strategies are being used to achieve high performance operation of linear drives. To maintain minimum volume and weight of the power supply unit on board the transportation vehicle, peak thrust per unit current operation is a desirable objective. True peak thrust per unit current through slip control is difficult to achieve because the parameters of linear induction machines vary during normal operation. This paper first develops a peak thrust per unit current control law based on the per-phase equivalent circuit for linear induction machines. The algorithm for identification of the variable parameters in induction machines is then presented. Application to an operational linear induction machine (LIM) demonstrates the utility of this algorithm. The control strategy is then simulated, based on an operational transit LIM, to show the capability of achieving true peak thrust operation for linear induction machines.
Ways for improvement of the LIU-5/5000 linear induction accelerator parameters
Bobylev, V.I.; Kapchinskij, I.M.; Lapitskij, Yu.Ya.; Plotnikov, V.K.; Chuvilo, I.V.
1987-01-01
The reasons of limitaions to increase the beam current and improve the quality of beam in the electron linear induction accelerator LIU-5/5000 are studied. The necessity to increase the voltage in the gaps of the electron gun, increase the diameter of the cathode and aperture of the drift tube, accuracy of axial symmetry electron gun current-carrying elements and accuracy of gun fabrication are shown. Stabilization of beam parameters require a new high voltage modulators. Different versions of the linac modernization with the use of transformers with cores of 430 and 600 mm are studied. Technical possibilities at several versions of high voltage modulators are discussed
Bidirectional pulser made from pulse lines for linear induction accelerators
Hotta, E.; Mori, T.; Kobayashi, T.; Okino, A.; Haginomori, E.; Ko, K.C.
1996-01-01
In order to obtain high-current charged particle beams, linear induction accelerators (LIA's) of two types have been already constructed. Conventional LIA's adopt a unidirectional pulse injected from an external pulser. The other LIA's, one of which has been proposed and constructed by Pavlovskii et al., have accelerating cavities made from pulse forming lines (PFL's). In this case, no magnetic core loaded in the cavity is necessary. However, the injected pulse must be a bidirectional one. Since a part of the voltage pulse with reversed polarity is used to accelerate a beam, it is possible to make the time integral of the output voltage zero. Thus the final magnetic energy stored in the cavity can be made zero at the end of the pulse, and the pulser-accelerator system attains the energy transfer efficiency of 100%. Accelerators of this type can be divided into two kinds, one of which has cavities with internal energy storage, and the other has cavities with energy injected from external bidirectional pulsers. The accelerator of latter type has been first proposed by Smith, but it has not been realized. Several bidirectional pulsers, which consist of three individual PFL's with arbitrary impedances and a closing switch, are analyzed. Output voltages are analytically calculated by using the method proposed by Dommel for digital computations of electromagnetic transients in networks, and conditions for attaining the maximum efficiency of energy transfer from the pulser to the beam are derived. Thus, 4 bidirectional pulsers of internal energy storage type and 2 of external pulse injection type with energy transfer efficiency of 100% are obtained, including the pulsers already reported by other authors
A simple model for induction core voltage distributions
Briggs, Richard J.; Fawley, William M.
2004-01-01
In fall 2003 T. Hughes of MRC used a full EM simulation code (LSP) to show that the electric field stress distribution near the outer radius of the longitudinal gaps between the four Metglas induction cores is very nonuniform in the original design of the DARHT-2 accelerator cells. In this note we derive a simple model of the electric field distribution in the induction core region to provide physical insights into this result. The starting point in formulating our model is to recognize that the electromagnetic fields in the induction core region of the DARHT-2 accelerator cells should be accurately represented within a quasi-static approximation because the timescale for the fields to change is much longer than the EM wave propagation time. The difficulty one faces is the fact that the electric field is a mixture of both a ''quasi-magnetostatic field'' (having a nonzero curl, with Bdot the source) and a ''quasi-electrostatic field'' (the source being electric charges on the various metal surfaces). We first discuss the EM field structure on the ''micro-scale'' of individual tape windings in Section 2. The insights from that discussion are then used to formulate a ''macroscopic'' description of the fields inside an ''equivalent homogeneous tape wound core region'' in Section 3. This formulation explicitly separates the nonlinear core magnetics from the quasi-electrostatic components of the electric field. In Section 4 a physical interpretation of the radial dependence of the electrostatic component of the electric field derived from this model is presented in terms of distributed capacitances, and the voltage distribution from gap to gap is related to various ''equivalent'' lumped capacitances. Analytic solutions of several simple multi-core cases are presented in Sections 5 and 6 to help provide physical insight into the effect of various proposed changes in the geometrical parameters of the DARHT-2 accelerator cell. Our results show that over most of the gap
Inductive voltage adder advanced hydrodynamic radiographic technology demonstration
Mazarakis, M.G.; Poukey, J.W.; Maenchen; Rovang, D.C.
1997-04-01
This paper presents the design, results, and analysis of a high-brightness electron beam technology demonstration experiment completed at Sandia National Laboratories, performed in collaboration with Los Alamos National Laboratory. The anticipated electron beam parameters were: 12 MeV, 35-40 kA, 0.5-mm rms radius, and 40-ns full width half maximum (FWHM) pulse duration. This beam, on an optimum thickness tantalum converter, should produce a very intense x-ray source of ∼ 1.5-mm spot size and 1 kR dose at sign 1 m. The accelerator utilized was SABRE, a pulsed inductive voltage adder, and the electron source was a magnetically immersed foilless electron diode. For these experiments, SABRE was modified to high-impedance negative-polarity operation. A new 100-ohm magnetically insulated transmission line cathode electrode was designed and constructed; the cavities were rotated 180 degrees poloidally to invert the central electrode polarity to negative; and only one of the two pulse forming lines per cavity was energized. A twenty- to thirty-Tesla solenoidal magnet insulated the diode and contained the beam at its extremely small size. These experiments were designed to demonstrate high electron currents in submillimeter radius beams resulting in a high-brightness high-intensity flash x-ray source for high-resolution thick-object hydrodynamic radiography. The SABRE facility high-impedance performance was less than what was hoped. The modifications resulted in a lower amplitude (9 MV), narrower-than-anticipated triangular voltage pulse, which limited the dose to ∼ 20% of the expected value. In addition, halo and ion-hose instabilities increased the electron beam spot size to > 1.5 mm. Subsequent, more detailed calculations explain these reduced output parameters. An accelerator designed (versus retrofit) for this purpose would provide the desired voltage and pulse shape
A model of annular linear induction pumps
Momozaki, Yoichi [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-10-27
The present work explains how the magnetic field and the induced current are obtained when the distributed coils are powered by a 3 phase power supply. From the magnetic field and the induced current, the thrust and the induction losses in the pump can be calculated to estimate the pump performance.
Induction linear accelerator technology for SDIO applications
Birx, D.; Reginato, L.; Rogers, D.; Trimble, D.
1986-11-01
The research effort reported concentrated primarily on three major activities. The first was aimed at improvements in the accelerator drive system of an induction linac to meet the high repetition rate requirements of SDI applications. The second activity centered on a redesign of the accelerator cells to eliminate the beam breakup instabilities, resulting in optimized beam transport. The third activity sought to improve the source of electrons to achieve a higher quality beam to satisfy the requirement of the free electron laser
Annular linear induction pump with an externally supported duct
1980-01-01
An annular linear induction pump of increased efficiency is described, capable of being readily disassembled for repair or replacement of parts, and having one pass flow of the liquid metal through the pump. (U.K.)
Study of linear induction motor characteristics : the Mosebach model
1976-05-31
This report covers the Mosebach theory of the double-sided linear induction motor, starting with the ideallized model and accompanying assumptions, and ending with relations for thrust, airgap power, and motor efficiency. Solutions of the magnetic in...
Study of linear induction motor characteristics : the Oberretl model
1975-05-30
The Oberretl theory of the double-sided linear induction motor (LIM) is examined, starting with the idealized model and accompanying assumptions, and ending with relations for predicted thrust, airgap power, and motor efficiency. The effect of varyin...
Comparison of linear synchronous and induction motors
2004-06-01
A propulsion prade study was conducted as part of the Colorado Maglev Project of FTA's Urban Maglev Technology Development Program to identify and evaluate prospective linear motor designs that could potentially meet the system performance requiremen...
Inductive energy storage using high voltage vacuum circuit breakers
McCann, R.B.; Woodson, H.H.; Mukutmoni, T.
1976-01-01
Controlled thermonuclear fusion experiments currently being planned require large amounts of pulsed energy. Inductive energy storage systems (IES) appear to be attractive for at least two applications in the fusion research program: high beta devices and those employing turbulent heating. The well-known roadblock to successful implementation of IES is the development of a reliable and cost-effective off-switch capable of handling high currents and withstanding high recovery voltages. The University of Texas at Austin has a program to explore the application of conventional vacuum circuit breakers designed for use in AC systems, in conjunction with appropriate counter pulse circuits, as off-switches in inductive energy storage systems. The present paper describes the IES employing vacuum circuit breakers as off-switches. Since the deionization property of these circuit breakers is of great importance to the design and the cost of the counter-pulse circuit, a synthetic test installation to test these breakers has been conceived, designed and is being installed in the Fusion Research Center, University of Texas at Austin. Some design aspects of the facility will be discussed here. Finally, the results of the study on a mathematical model developed and optimized to determine the least cost system which meets both the requirements of an off-switch for IES Systems and the ratings of circuit breakers used in power systems has been discussed. This analysis indicates that the most important factor with respect to the system cost is the derating of the circuit breakers to obtain satisfactory lifetimes
Test Stand for Linear Induction Accelerator Optimization
Ong, M; DeHope, B; Griffin, K; Goerz, D; Kihara, R; Vogtlin, G; Zentler, J M; Scarpetti, R
2003-01-01
Lawrence Livermore National Laboratory has designed and constructed a test stand to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot size. Studying the interaction of the beam and pulse-power system with the accelerator cell will improve the design of high-current accelerators at Livermore and elsewhere. On the test stand, a standard FXR cell is driven by a flexible pulse-power system and the beam current is simulated with a switched center conductor. The test stand is fully instrumented with high-speed digitizers to document the effect of impedance mismatches when the cell is operated under various full-voltage conditions. A time-domain reflectometry technique was also developed to characterize the beam and cell interactions by measuring the impedance of the accelerator and pulse-power component. Computer models are being developed in parallel with the testing program to validate the measurements and evaluate different design changes. Both 3D transient electromagnetic and circuit models are being used
Effect of inductance between middle and outer cylinders on diode voltage of pulse forming line
Liu Jinliang; Wang Xinxin
2008-01-01
Based on the experimental device of the water spiral pulse forming line(PFL) type electron beam accelerator, the effect of inductance between the middle and outer cylinders of PFL on diode voltage is theoretically and experimentally studied in this paper. The formulae are introduced, with which the effect of inductance on diode voltage is calculated. In addition, the diode voltage waveform is simulated through the Pspice software. The theoretical and simulated results agree well with the experimental results, which show that large inductance between middle and outer cylinders can shorten the waveform flat part of diode voltage, increase waveform rise time and reduce the diode peak voltage. When the inductance is smaller than 200 nH, a nearly square voltage waveform can be obtained in field-emission diode. (authors)
Prediction of windings temperature rise in induction motors supplied with distorted voltage
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)
Prediction of windings temperature rise in induction motors supplied with distorted voltage
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
Linear induction accelerator approach for advanced radiography
Caporaso, G.J.
1997-05-01
Recent advances in induction accelerator technology make it possible to envision a single accelerator that can serve as an intense, precision multiple pulse x-ray source for advanced radiography. Through the use of solid-state modulator technology repetition rates on the order of 1 MHz can be achieved with beam pulse lengths ranging from 200 ns to 2 microsecs. By using fast kickers, these pulses may be sectioned into pieces which are directed to different beam lines so as to interrogate the object under study from multiple lines of sight. The ultimate aim is to do a time dependent tomographic reconstruction of a dynamic object. The technology to accomplish these objectives along with a brief discussion of the experimental plans to verify it will be presented
Zhang Yong; Yang Jianhong; Cai Xueyuan; Wang Zaixing
2010-01-01
The exponential dependence of the potential barrier height φ c on the biased voltages of the inorganic/organic static induction transistor (SIT/OSIT) through a normalized approach in the low-current regime is presented. It shows a more accurate description than the linear expression of the potential barrier height. Through the verification of the numerical calculated and experimental results, the exponential dependence of φ c on the applied biases can be used to derive the I-V characteristics. For both SIT and OSIT, the calculated results, using the presented relationship, are agreeable with the experimental results. Compared to the previous linear relationship, the exponential description of φ c can contribute effectively to reduce the error between the theoretical and experimental results of the I-V characteristics. (semiconductor devices)
Beam dynamics in stripline linear induction accelerators
Adler, R.J.
1983-01-01
Stripline (parallel plate transmission line) pulsed power modules have been considered for application to advanced high current linear accelerators. Some advantages of the stripline designs include compact size, easy maintenance, and most importantly, the small number of switches required (one switch per 2 MeV). The principle drawback of stripline designs is that they impart a NET transverse force to particles in the gap. This is shown to result in randomized transverse momentum, and NET, constructive transverse guiding center motion. In this paper, a semi-quantitative analysis of several facets of the problem is presented
A speed estimation unit for induction motors based on adaptive linear combiner
Marei, Mostafa I.; Shaaban, Mostafa F.; El-Sattar, Ahmed A.
2009-01-01
This paper presents a new induction motor speed estimation technique, which can estimate the rotor resistance as well, from the measured voltage and current signals. Moreover, the paper utilizes a novel adaptive linear combiner (ADALINE) structure for speed and rotor resistance estimations. This structure can deal with the multi-output systems and it is called MO-ADALINE. The model of the induction motor is arranged in a linear form, in the stationary reference frame, to cope with the proposed speed estimator. There are many advantages of the proposed unit such as wide speed range capability, immunity against harmonics of measured waveforms, and precise estimation of the speed and the rotor resistance at different dynamic changes. Different types of induction motor drive systems are used to evaluate the dynamic performance and to examine the accuracy of the proposed unit for speed and rotor resistance estimation.
Bouzid, Allal; Sicard, Pierre; Guerrero, Josep M.
2015-01-01
This paper presents a comprehensive modeling of a three-phase cage induction machine used as a self-excited squirrel-cage induction generator (SEIG), and discusses the regulation of the voltage and frequency of a self-excited SEIG based on the action of the static synchronous Compensator (STATCOM......). The STATCOM with the proposed controller consists of a three-phase voltage-sourced inverter and a DC voltage. The compensator can provide the active and reactive powers and regulate AC system bus voltage and the frequency, but also may enhance the load stability. Moreover, a feed forward control method...
Linear induction accelerators made from pulse-line cavities with external pulse injection
Smith, I.
1979-01-01
Two types of linear induction accelerator have been reported previously. In one, unidirectional voltage pulses are generated outside the accelerator and injected into the accelerator cavity modules, which contain ferromagnetic material to reduce energy losses in the form of currents induced, in parallel with the beam, in the cavity structure. In the other type, the accelerator cavity modules are themselves pulse-forming lines with energy storage and switches; parallel current losses are made zero by the use of circuits that generate bidirectional acceleration waveforms with a zero voltage-time integral. In a third type of design described here, the cavities are externally driven, and 100% efficient coupling of energy to the beam is obtained by designing the external pulse generators to produce bidirectional voltage waveforms with zero voltage-time integral. A design for such a pulse generator is described that is itself one hundred percent efficient and which is well suited to existing pulse power techniques. Two accelerator cavity designs are described that can couple the pulse from such a generator to the beam; one of these designs provides voltage doubling. Comparison is made between the accelerating gradients that can be obtained with this and the preceding types of induction accelerator
Zhang, Shuping; Zhao, Chen; Tan, Weipu
2017-05-01
The majority important load of industrial area is mainly composed of induction motor, it is more common that induction motor becomes sluggishness and even tripping due to the lose of power supply or other malfunction in the practical work. In this paper, space vector method is used to establish a reduced order model of induction motor, and then study the changes of motor electromagnetic after losing electricity. Based on motion equations of the rotor and magnetic flux conservation principle, it uses mathematical methods to deduce the expression of rotor current, rotor flux, the stator flux and the residual voltage of stator side. In addition, relying on thermal power plants, it uses the actual data of power plants, takes DIgsilent software to simulate the residual voltage of motor after losing electricity. analyses the influence on the residual voltage with the changes of the moment of inertia, load ratio, initial size of slip and the load characteristic of induction motor. By analysis of these, it has a more detailed understanding about the changes of residual voltage in practical application, in additional, it is more beneficial to put into standby power supply safely and effectively, moreover, reduce the influence of the input process to the whole system.
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)
Force analysis of linear induction motor for magnetic levitation system
Kuijpers, A.A.; Nemlioglu, C.; Sahin, F.; Verdel, A.J.D.; Compter, J.C.; Lomonova, E.
2010-01-01
This paper presents the analyses of thrust and normal forces of linear induction motor (LIM) segments which are implemented in a rotating ring system. To obtain magnetic levitation in a cost effective and sustainable way, decoupled control of thrust and normal forces is required. This study includes
Evaluation of linear induction motor characteristics : the Yamamura model
1975-04-30
The Yamamura theory of the double-sided linear induction motor (LIM) excited by a constant current source is discussed in some detail. The report begins with a derivation of thrust and airgap power using the method of vector potentials and theorem of...
Direct Torque Control With Feedback Linearization for Induction Motor Drives
Lascu, Cristian; Jafarzadeh, Saeed; Fadali, Sami M.
2017-01-01
This paper describes a direct-torque-controlled (DTC) induction motor (IM) drive that employs feedback linearization and sliding-mode control (SMC). A new feedback linearization approach is proposed, which yields a decoupled linear IM model with two state variables: torque and stator flux magnitude....... This intuitive linear model is used to implement a DTC-type controller that preserves all DTC advantages and eliminates its main drawback, the flux and torque ripple. Robust, fast, and ripple-free control is achieved by using SMC with proportional control in the vicinity of the sliding surface. SMC assures...... in simulations. The sliding controller is compared with a linear DTC scheme with and without feedback linearization. Extensive experimental results for a sensorless IM drive validate the proposed solution....
Tuning the DARHT Axis-II linear induction accelerator focusing
Ekdahl, Carl A. [Los Alamos National Laboratory
2012-04-24
Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an
Jairo Blanco; Ruben Darío Leal; Jonathan Jacome; Johann F. Petit; Gabriel Ordoñez; Víctor Barrera
2011-01-01
This article presents an analysis of voltage sag propagation. The ATPDraw tool was selected for simulating the IEEE 34 node test feeder. It takes into account both voltage sags caused by electrical fault network, as well as voltage sag propagation characteristics caused by induction motor starting and transformer energising. The analysis was aimed at assessing the influence of transformer winding connections, the impedance of these transformers, lines and cables, summarising the...
Sodium flow rate measurement method of annular linear induction pump
Araseki, Hideo
2011-01-01
This report describes a method for measuring sodium flow rate of annular linear induction pumps arranged in parallel and its verification result obtained through an experiment and a numerical analysis. In the method, the leaked magnetic field is measured with measuring coils at the stator end on the outlet side and is correlated with the sodium flow rate. The experimental data and the numerical result indicate that the leaked magnetic field at the stator edge keeps almost constant when the sodium flow rate changes and that the leaked magnetic field change arising from the flow rate change is small compared with the overall leaked magnetic field. It is shown that the correlation between the leaked magnetic field and the sodium flow rate is almost linear due to this feature of the leaked magnetic field, which indicates the applicability of the method to small-scale annular linear induction pumps. (author)
SANJAY. A. DEOKAR,; Dr. L. M. WAGHMARE
2010-01-01
This paper suggests methods for estimating short time flicker (PST) severity on 22/3.3 kV network supplying induction motor loads of municipal integrated water pumping system. The impact of additional connection of induction motors to the same system has been analyzed. Measurements are done at the point of common coupling (PCC) to identify background short time flicker levels and the contribution of the already operating induction motors. The paper also analyses and compares different voltage...
Direct torque control with feedback linearization for induction motor drives
Lascu, Cristian; Jafarzadeh, Saeed; Fadali, Sami M.
2015-01-01
This paper describes a Direct Torque Controlled (DTC) Induction Machine (IM) drive that employs feedback linearization and sliding-mode control. A feedback linearization approach is investigated, which yields a decoupled linear IM model with two state variables: torque and stator flux magnitude....... This intuitive linear model is used to implement a DTC type controller that preserves all DTC advantages and eliminates its main drawback, the flux and torque ripple. Robust, fast, and ripple-free control is achieved by using Variable Structure Control (VSC) with proportional control in the vicinity...... robust stability analysis are presented. The sliding controller is compared with a linear DTC scheme, and experimental results for a sensorless IM drive validate the proposed solution....
Core reset system design for linear induction accelerator
Durga Praveen Kumar, D.; Mitra, S.; Sharma, Archana; Nagesh, K.V.; Chakravarthy, D.P.
2006-01-01
A repetitive pulsed power system based Linear Induction Accelerator (LIA-200) is being developed at BARC to get an electron beam of 200keV, 5kA, 50ns, 10-100 Hz. Amorphous core is the heart of these accelerators. It serves various functions in different subsystems viz. pulse power modulator, pulse transformer, magnetic switches and induction cavities. One of the factors that make the magnetic components compact is utilization of the total flux swing available in the core. In the present system, magnetic switches, pulse transformers, and induction cavity are designed to avail the full flux swing available in the core. For achieving this objective, flux density in the core has to be kept at the reverse saturation, before the main pulse is applied. The electrical circuit which makes it possible is called the core reset system. In this paper the details of core reset system designed for LIA-200 are described. (author)
Cost optimization of induction linac drivers for linear colliders
Barletta, W.A.
1986-01-01
Recent developments in high reliability components for linear induction accelerators (LIA) make possible the use of these devices as economical power drives for very high gradient linear colliders. A particularly attractive realization of this ''two-beam accelerator'' approach is to configure the LIA as a monolithic relativistic klystron operating at 10 to 12 GHz with induction cells providing periodic reacceleration of the high current beam. Based upon a recent engineering design of a state-of-the-art, 10- to 20-MeV LIA at Lawrence Livermore National Laboratory, this paper presents an algorithm for scaling the cost of the relativistic klystron to the parameter regime of interest for the next generation high energy physics machines. The algorithm allows optimization of the collider luminosity with respect to cost by varying the characteristics (pulse length, drive current, repetition rate, etc.) of the klystron. It also allows us to explore cost sensitivities as a guide to research strategies for developing advanced accelerator technologies
Study on quench detection of the KSTAR CS coil with CDA+MIK compensation of inductive voltages
An, Seok Chan; Kim, Jin Sub [Yonsei University, Seoul (Korea, Republic of); Chu, Yong [National Fusion Research Institute(NFRI), Daejeon (Korea, Republic of)
2016-03-15
Quench Detection System (QDS) is essential to guarantee the stable operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) Poloidal Field (PF) magnet system because the stored energy in the magnet system is very large. For the fast response, voltage-based QDS has been used. Co-wound voltage sensors and balanced bridge circuits were applied to eliminate the inductive voltages generated during the plasma operation. However, as the inductive voltages are hundreds times higher than the quench detection voltage during the pulse-current operation, Central Difference Averaging (CDA) and MIK, where I and K stand for mutual coupling indexes of different circuits, which is an active cancellation of mutually generated voltages have been suggested and studied. In this paper, the CDA and MIK technique were applied to the KSTAR magnet for PF magnet quench detection. The calculated inductive voltages from the MIK and measured voltages from the CDA circuits were compared to eliminate the inductive voltages at result signals.
Study on quench detection of the KSTAR CS coil with CDA+MIK compensation of inductive voltages
An, Seok Chan; Kim, Jin Sub; Chu, Yong
2016-01-01
Quench Detection System (QDS) is essential to guarantee the stable operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) Poloidal Field (PF) magnet system because the stored energy in the magnet system is very large. For the fast response, voltage-based QDS has been used. Co-wound voltage sensors and balanced bridge circuits were applied to eliminate the inductive voltages generated during the plasma operation. However, as the inductive voltages are hundreds times higher than the quench detection voltage during the pulse-current operation, Central Difference Averaging (CDA) and MIK, where I and K stand for mutual coupling indexes of different circuits, which is an active cancellation of mutually generated voltages have been suggested and studied. In this paper, the CDA and MIK technique were applied to the KSTAR magnet for PF magnet quench detection. The calculated inductive voltages from the MIK and measured voltages from the CDA circuits were compared to eliminate the inductive voltages at result signals
Linear induction accelerators for fusion and neutron production
Barletta, W.A.; California Univ., Los Angeles, CA
1993-08-01
Linear induction accelerators (LIA) with pulsed power drives can produce high energy, intense beams or electrons, protons, or heavy ions with megawatts of average power. The continuing development of highly reliable LIA components permits the use such accelerators as cost-effective beam sources to drive fusion pellets with heavy ions, to produce intense neutron fluxes using proton beams, and to generate with electrons microwave power to drive magnetic fusion reactors and high gradient, rf-linacs
Cheng Qifeng; Ni Jianping; Meng Cui; Cheng Cheng; Liu Yinong; Li Jin
2009-01-01
The close of high voltage switch in pulsed power system of linear induction accelerator often radiates strong transient electric field, which may influence ambient sensitive electric equipment, signals and performance of other instruments, etc. By performing gridded measurement around the Marx generator, the general distribution law and basic characters of electric field radiation are summarized. The current signal of the discharge circuit is also measured, which demonstrates that the current and the radiated electric field both have a resonance frequency about 150 kHz, and contain much higher frequency components. (authors)
Diagnosis of voltage collapse due to induction motor stalling using static analysis
Karbalaei, F.; Kalantar, M.; Kazemi, A.
2008-01-01
Induction motor stalling is one of the important reasons for voltage collapse. This paper presents that, for induction motor stalling diagnosis, it is not necessary to use a third or first order dynamic model of induction motors. Instead, a method is presented based on algebraic calculations for which the steady state model of the induction motor considering different kinds of mechanical loads (constant and variable torque) is added to the power flow equations. Simulation results for a simple system confirm the correctness of the proposed method as compared to dynamic simulation results
Linear variable voltage diode capacitor and adaptive matching networks
Larson, L.E.; De Vreede, L.C.N.
2006-01-01
An integrated variable voltage diode capacitor topology applied to a circuit providing a variable voltage load for controlling variable capacitance. The topology includes a first pair of anti-series varactor diodes, wherein the diode power-law exponent n for the first pair of anti-series varactor
Preliminary results of Linear Induction Accelerator LIA-200
Sharma, Archana; Senthil, K; Kumar, D D Praveen; Mitra, S; Sharma, V; Patel, A; Sharma, D K; Rehim, R; Kolge, T S; Saroj, P C; Acharya, S; Amitava, Roy; Rakhee, M; Nagesh, K V; Chakravarthy, D P, E-mail: aroy@barc.gov.i, E-mail: arsharma@barc.gov.i [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2010-05-15
Repetitive Pulsed Power Technology is being developed keeping in mind the potential applications of this technology in material modifications, disinfections of water, timber, and food pasteurization etc. BARC has indigenously developed a Linear Induction Accelerator (LIA-200) rated for 200 kV, 4 kA, 100 ns, 10 Hz. The satisfactory performance of all the sub-systems including solid state power modulator, amorphous core based pulsed transformers, magnetic switches, water capacitors, water pulse- forming line, induction adder and field-emission diode have been demonstrated. This paper presents some design details and operational results of this pulsed power system. It also highlights the need for further research and development to build reliable and economic high-average power systems for industrial applications.
Comparison of Linear Induction Motor Theories for the LIMRV and TLRV Motors
1978-01-01
The Oberretl, Yamamura, and Mosebach theories of the linear induction motor are described and also applied to predict performance characteristics of the TLRV & LIMRV linear induction motors. The effect of finite motor width and length on performance ...
Sodium flow rate measurement method of annular linear induction pumps
Araseki, Hideo; Kirillov, Igor R.; Preslitsky, Gennady V.
2012-01-01
Highlights: ► We found a new method of flow rate monitoring of electromagnetic pump. ► The method is very simple and does not require a large space. ► The method was verified with an experiment and a numerical analysis. ► The experimental data and the numerical results are in good agreement. - Abstract: The present paper proposes a method for measuring sodium flow rate of annular linear induction pumps. The feature of the method lies in measuring the leaked magnetic field with measuring coils near the stator end on the outlet side and in correlating it with the sodium flow rate. This method is verified through an experiment and a numerical analysis. The data obtained in the experiment reveals that the correlation between the leaked magnetic field and the sodium flow rate is almost linear. The result of the numerical analysis agrees with the experimental data. The present method will be particularly effective to sodium flow rate monitoring of each one of plural annular linear induction pumps arranged in parallel in a vessel which forms a large-scale pump unit.
Induction linear accelerators for commercial photon irradiation processing
Matthews, S.M.
1989-01-01
A number of proposed irradiation processes requires bulk rather than surface exposure with intense applications of ionizing radiation. Typical examples are irradiation of food packaged into pallet size containers, processing of sewer sludge for recycling as landfill and fertilizer, sterilization of prepackaged medical disposals, treatment of municipal water supplies for pathogen reduction, etc. Volumetric processing of dense, bulky products with ionizing radiation requires high energy photon sources because electrons are not penetrating enough to provide uniform bulk dose deposition in thick, dense samples. Induction Linear Accelerator (ILA) technology developed at the Lawrence Livermore National Laboratory promises to play a key role in providing solutions to this problem. This is discussed in this paper
NASTRAN buckling study of a linear induction motor reaction rail
Williams, J. G.
1973-01-01
NASTRAN was used to study problems associated with the installation of a linear induction motor reaction rail test track. Specific problems studied include determination of the critical axial compressive buckling stress and establishment of the lateral stiffness of the reaction rail under combined loads. NASTRAN results were compared with experimentally obtained values and satisfactory agreement was obtained. The reaction rail was found to buckle at an axial compressive stress of 11,400 pounds per square inch. The results of this investigation were used to select procedures for installation of the reaction rail.
Hiroyuki Wakiwaka
2011-11-01
Full Text Available This paper discusses the effect of inductive coil shape on the sensing performance of a linear displacement sensor. The linear displacement sensor consists of a thin type inductive coil with a thin pattern guide, thus being suitable for tiny space applications. The position can be detected by measuring the inductance of the inductive coil. At each position due to the change in inductive coil area facing the pattern guide the value of inductance is different. Therefore, the objective of this research is to study various inductive coil pattern shapes and to propose the pattern that can achieve good sensing performance. Various shapes of meander, triangular type meander, square and circle shape with different turn number of inductive coils are examined in this study. The inductance is measured with the sensor sensitivity and linearity as a performance evaluation parameter of the sensor. In conclusion, each inductive coil shape has its own advantages and disadvantages. For instance, the circle shape inductive coil produces high sensitivity with a low linearity response. Meanwhile, the square shape inductive coil has a medium sensitivity with higher linearity.
Xue, Ning; Cho, Sung-Hoon; Chang, Sung-Pil; Lee, Jeong-Bong
2012-01-01
The main strategy for wireless power transfer to implantable devices is to use inductive coupling technology. The induced voltage of implanted devices highly depends on factors such as mutual inductance between the external transmitter coil and the receiver coil, quality factor of the receiver circuit and operation frequency. In this paper, the mutual inductance under a variety of geometries of external coil and under the condition of different vertical distances, lateral displacements and angular misalignments between two coils were theoretically calculated and simulated. To ascertain the condition of maximum power transmission for certain coils’ position requirements, an LC tank (2.7 mm × 2 mm) consisting of a microfabricated gold inductor coil and a small surface mounted capacitor was designed and fabricated as the telemetric part of a neurostimulator. The induced voltage of the LC tank was measured in both air and artificial tissue media under different sizes of power coil and operation frequencies. As a result, the optimum size of a transmitter coil is selected to be of 4 mm inner radius with six turns of coil, while the whole coupling system operates at 94 MHz resonant frequency within 5–11 mm vertical distance, 0–4 mm lateral and 0°–50° angular misalignment between two coils. With the change of the above coils’ positions, the measured induced voltage drops within 30%, satisfying the surgical requirement for neurostimulator implantation. (paper)
Development of a linear induction motor based artificial muscle system.
Gruber, A; Arguello, E; Silva, R
2013-01-01
We present the design of a linear induction motor based on electromagnetic interactions. The engine is capable of producing a linear movement from electricity. The design consists of stators arranged in parallel, which produce a magnetic field sufficient to displace a plunger along its axial axis. Furthermore, the winding has a shell and cap of ferromagnetic material that amplifies the magnetic field. This produces a force along the length of the motor that is similar to that of skeletal muscle. In principle, the objective is to use the engine in the development of an artificial muscle system for prosthetic applications, but it could have multiple applications, not only in the medical field, but in other industries.
Regulation of an Induction Motor under Broad Changes in DC-Link Voltage
Kokeš, Petr; Semerád, Radko
2006-01-01
Roč. 51, č. 4 (2006), s. 363-394 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction motor (IM) * DC-link voltage drop * stator flux vector control (SFVC) Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Rotor Voltage Dynamics in the Doubly Fed Induction Generator During Grid Faults
Lima, Francisco K. A.; Luna, Alvaro; Rodriguez, Pedro
2010-01-01
This paper presents a new control strategy for the rotor-side converter (RSC) of wind turbines (WTs) based on doubly fed induction generators (DFIG) that intends to improve its low-voltage ride through capability. The main objective of this work is to design an algorithm that would enable the sys...
Effects of symmetrical voltage sags on squirrel-cage induction motors
Pedra, Joaquin; Sainz, Luis; Corcoles, Felipe [Department of Electrical Engineering, ETSEIB-UPC, Av. Diagonal, 647, 08028 Barcelona (Spain)
2007-10-15
This paper analyzes the symmetrical voltage sag consequences on the induction motor behavior when single- and double-cage models are considered, namely current and torque peaks, and speed loss. These effects depend on several variables like sag type, duration and depth. Voltage sag effects are studied by using single- and double-cage models for three motors of different rated power. The double-cage model always predicts torque and current peaks higher than those of the single-cage model. The single-cage model predicts that voltage sags can produce motor instability, whereas the double-cage model is always stable. Therefore, the double-cage model must be used for the simulation of the squirrel-cage induction motor, because the single-cage model can give erroneous results in some situations. (author)
A Differential Monolithically Integrated Inductive Linear Displacement Measurement Microsystem
Matija Podhraški
2016-03-01
Full Text Available An inductive linear displacement measurement microsystem realized as a monolithic Application-Specific Integrated Circuit (ASIC is presented. The system comprises integrated microtransformers as sensing elements, and analog front-end electronics for signal processing and demodulation, both jointly fabricated in a conventional commercially available four-metal 350-nm CMOS process. The key novelty of the presented system is its full integration, straightforward fabrication, and ease of application, requiring no external light or magnetic field source. Such systems therefore have the possibility of substituting certain conventional position encoder types. The microtransformers are excited by an AC signal in MHz range. The displacement information is modulated into the AC signal by a metal grating scale placed over the microsystem, employing a differential measurement principle. Homodyne mixing is used for the demodulation of the scale displacement information, returned by the ASIC as a DC signal in two quadrature channels allowing the determination of linear position of the target scale. The microsystem design, simulations, and characterization are presented. Various system operating conditions such as frequency, phase, target scale material and distance have been experimentally evaluated. The best results have been achieved at 4 MHz, demonstrating a linear resolution of 20 µm with steel and copper scale, having respective sensitivities of 0.71 V/mm and 0.99 V/mm.
Analysis of magnetohydrodynamic flow in linear induction EM pump
Geun Jong Yoo; Choi, H.K.; Eun, J.J.; Bae, Y.S.
2005-01-01
Numerical analysis is performed for magnetic and magnetohydrodynamic (MHD) flow fields in linear induction type electromagnetic (EM) pump. A finite volume method is applied to solve magnetic field governing equations and the Navier-Stokes equations. Vector and scalar potential methods are adopted to obtain the electric and magnetic fields and the resulting Lorentz force in solving Maxwell equations. The magnetic field and velocity distributions are found to be influenced by the phase of applied electric current. Computational results indicate that the magnetic flux distribution with changing phase of input electric current is characterized by pairs of counter-rotating closed loops. The velocity distributions are affected by the intensity of Lorentz force. The governing equations for the magnetic and flow fields are only semi-coupled in this study, therefore, further study with fully-coupled governing equations are required. (authors)
Recent advances in kicker pulser technology for linear induction accelerators
Chen, Y. J.; Cook, E.; Davis, B.; Dehope, W. J.; Yen, B.
1999-01-01
Recent progress in the development and understanding of linear induction accelerator have produced machines with 10s of MeV of beam energy and multi-kiloampere currents. Near-term machines, such as DARHT-2, are envisioned with microsecond pulselengths. Fast beam kickers, based on cylindrical electromagnetic stripline structures, will permit effective use of these extremely high-energy beams in an increasing number of applications. In one application, radiography, kickers were an essential element in resolving temporal evolution of hydrodynamic events by cleaving out individual pulses from long, microsecond beams. Advanced schemes are envisioned where these individual pulses are redirected through varying length beam lines and suitably recombined for stereographic imaging or tomographic reconstruction. Recent advances in fast kickers and their pulsed power technology are described. Kicker pulsers based on both planar triode and all solid-state componentry are discussed and future development plans are presented
Technology demonstration for the DARHT linear induction accelerators
Burns, M.; Allison, P.; Downing, J.; Moir, D.; Caporaso, G.; Chen, Y.J.
1992-01-01
The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two 16-MeV, 3-kA Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. Technology demonstration of the key accelerator sub-systems is underway at the DARHT Integrated Test Stand (ITS), which will produce a 6-MeV, 3-kA, 60-ns flattop electron beam. We will summarized measurements of ITS injector, pulsed-power, and accelerator cell performance. Time-resolved measurements of the electron beam parameters will also be presented. These measurements indicate that the DARHT accelerator design is sufficiently advanced to provide the high quality electron beams required for radiography with sub-millimeter spatial resolution
Technology demonstration for the DARHT linear induction accelerators
Burns, M.; Allison, P.; Downing, J.; Moir, D.; Caporaso, G.; Chen, Y.J.
1993-01-01
The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two 16-MeV, 3-kA Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. Technology demonstration of the key accelerator sub-systems is underway at the DARHT Integrated Test Stand (ITS), which will produce a 6-MeV, 3-kA, 60-ns flattop electron beam. The authors summarize measurements of ITS injector, pulsed-power, and accelerator cell performance. Time-resolved measurements of the electron beam parameters are also presented. These measurements indicate that the DARHT accelerator design is sufficiently advanced to provide the high quality electron beams required for radiography with sub-millimeter spatial resolution
Improved focus solenoid design for linear induction accelerators
Zentler, J.M.; Van Maren, R.D.; Nexsen, W.E.
1992-08-01
Our FXR linear induction accelerator produces a 2 KA, 17 MeV electron beam of 60 ns duration. The beam is focused on a tantalum target to produce x-rays for radiography. The FWHM spot size of the focused beam is currently 2.2 mm. We strive to reduce the spot size by 30% by improving the field characteristics of focusing solenoids housed in each of 50 induction cells along the beamline. Tilts in the magnetic axis of the existing solenoids range up to 12 mrad (0.7 degrees). We are building new solenoid assemblies which include ferromagnetic homogenizer rings. These dramatically reduce field errors. A field tilt of under 0.5 mrad has been achieved. Mechanical alignment of the rings is critical. We developed a novel construction method in which the rings are wound with 4 mil thick Si-Fe ribbon into grooves on an aluminum cylinder. The cylinder then becomes the winding mandrel for the focus solenoids. This forms a more accurate and compact assembly than the standard practice of pressing individual solid rings onto a tube
Multipurpose 5-MeV linear induction accelerator
Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.
1984-01-01
Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, the researchers used new technology to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The paper describes the scheme. The magnetic drive system can be tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization
Development of a Low Inductance Linear Alternator for Stirling Power Convertors
Geng, Steven M.; Schifer, Nicholas A.
2017-01-01
The free-piston Stirling power convertor is a promising technology for high efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper, eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations, and compares the predictions with experimental data for one of the configurations that has been built and is currently being tested.
Development of a Low-Inductance Linear Alternator for Stirling Power Convertors
Geng, Steven M.; Schifer, Nicholas A.
2017-01-01
The free-piston Stirling power convertor is a promising technology for high-efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-the-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations. Additionally, one of the configurations was built and tested at GRC, and the experimental data is compared with the predictions.
A Method for Solving the Voltage and Torque Equations of the Split-Phase Induction Machines
G. A. Olarinoye
2013-06-01
Full Text Available Single phase induction machines have been the subject of many researches in recent times. The voltage and torque equations which describe the dynamic characteristics of these machines have been quoted in many papers, including the papers that present the simulation results of these model equations. The way and manner in which these equations are solved is not common in literature. This paper presents a detailed procedure of how these equations are to be solved with respect to the splitphase induction machine which is one of the different types of the single phase induction machines available in the market. In addition, these equations have been used to simulate the start-up response of the split phase induction motor on no-load. The free acceleration characteristics of the motor voltages, currents and electromagnetic torque have been plotted and discussed. The simulation results presented include the instantaneous torque-speed characteristics of the Split phase Induction machine. A block diagram of the method for the solution of the machine equations has also been presented.
Simple mechanical parameters identification of induction machine using voltage sensor only
Horen, Yoram; Strajnikov, Pavel; Kuperman, Alon
2015-01-01
Highlights: • A simple low cost algorithm for induction motor mechanical parameters estimation is proposed. • Voltage sensing only is performed; speed sensor is not required. • The method is suitable for both wound rotor and squirrel cage motors. - Abstract: A simple low cost algorithm for induction motor mechanical parameters estimation without speed sensor is presented in this paper. Estimation is carried out by recording stator terminal voltage during natural braking and subsequent offline curve fitting. The algorithm allows accurately reconstructing mechanical time constant as well as loading torque speed dependency. Although the mathematical basis of the presented method is developed for wound rotor motors, it is shown to be suitable for squirrel cage motors as well. The algorithm is first tested by reconstruction of simulation model parameters and then by processing measurement results of several motors. Simulation and experimental results support the validity of the proposed algorithm
Derating of an induction machine under voltage unbalance combined with over or undervoltages
Gnacinski, P.
2009-01-01
This work deals with the load carrying capacity of an induction cage machine under voltage unbalance combined with over- or undervoltage. The effect of complex voltage unbalance factor (CVUF) angle on the derating factor is taken into consideration. The derating curves obtained with two different methods are compared. The machine efficiency, stator currents and temperature-rise distribution after applying the required derating factor are discussed. The results of experimental investigations and computer calculations are presented for two low-power induction motors of opposite properties. One of them has a comparatively weakly saturated magnetic circuit and is especially exposed to the risk of overheating for undervoltage. The other investigated machine has a comparatively strongly saturated magnetic circuit and is especially exposed to overheating in the conditions of overvoltage
Derating of an induction machine under voltage unbalance combined with over or undervoltages
Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska St. 83, 81-225 Gdynia (Poland)
2009-04-15
This work deals with the load carrying capacity of an induction cage machine under voltage unbalance combined with over- or undervoltage. The effect of complex voltage unbalance factor (CVUF) angle on the derating factor is taken into consideration. The derating curves obtained with two different methods are compared. The machine efficiency, stator currents and temperature-rise distribution after applying the required derating factor are discussed. The results of experimental investigations and computer calculations are presented for two low-power induction motors of opposite properties. One of them has a comparatively weakly saturated magnetic circuit and is especially exposed to the risk of overheating for undervoltage. The other investigated machine has a comparatively strongly saturated magnetic circuit and is especially exposed to overheating in the conditions of overvoltage. (author)
Dragon-I injector based on the induction voltage adder technique
Zhang Kaizhi
2006-08-01
Full Text Available The Dragon-I injector based on the induction voltage adder technique is introduced. Twelve ferrite loaded induction cells are connected in a series through central conducting stalks to achieve a pulsed voltage higher than 3.5 MV across the diode. Electrons are extracted from the velvet emitter and guided through the anode pipe by the magnets placed inside the cathode and anode shrouds. Measurements at the exit of injector show that, with an electric field of 200 kV/cm near the velvet surface and suitable magnetic field distribution, an electron beam up to 2.8 kA can be obtained with a normalized emittance of 1040π mm mrad, and energy spread of 2.1% (3σ around the central energy of 3.5 MeV.
Voltage harmonic variation in three-phase induction motors with different coil pitches
Deshmukh, Ram; Moses, Anthony John; Anayi, Fatih
2006-01-01
A pulse-width modulation (PWM) inverter feeding four different chorded three-phase induction motors was tested for low-order odd harmonic voltage component and efficiency at different loads. Total harmonic distortion (THD) due to 3rd, 5th and 9th harmonics was less in a motor with 160 o coil pitch. Particular harmonic order for each coil pitch was suppressed and the efficiency of a 120 o coil pitch motor was increased by 7.5%
Induction and Conduction Electromagnetic Waves Caused by Lightning Strike on the Low Voltage Network
Reynaldo Zoro
2010-10-01
Full Text Available Direct and indirect lightning strikes can disturb and induce low voltage overheadlines and it can produced overvoltage due to traveling waves along the lines. This overvoltage can damage the equipments connected to it. It was recorded that there were already a lot of damages of electronic equipments and arrestesr located inside the building of Lightning Measurement Station at Mnt. Tangkuban Perahu. Most of the overvoltage which was developed on the low voltage lines were coming from indirect lightning strike nearby due to the fact that most of the lines were covered by trees. Research was carried out to study and evaluate the induction and conduction of the lightning strikes to the LV lines that can lead to the cause of equipment and arrester damages inside the building. Local lightning data for the analysis were derived from measurement system installed at the stations and historical lightning data from lightning detection network called Jadpen (National Lightning Detection Network. The data was used for calculating and evaluating the voltage elevation, induction voltage profiles and conduction in the form of traveling waves using Rusck Model. Two damaged arresters were evaluated and compared and it give the better understanding on how the protection system work.Keywords:
The LLNL Flash X-Ray Induction Linear Accelerator (FXR)
Multhauf, L G
2002-01-01
The FXR is an induction linear accelerator used for high-speed radiography at the Lawrence Livermore National Laboratory's Experimental Test Site. It was designed specifically for the radiography of very thick explosive objects. Since its completion in 1982, it has been very actively used for a large variety of explosives tests, and has been periodically upgraded to achieve higher performance. Upgrades have addressed machine reliability, radiographic sensitivity and resolution, two-frame imaging by double pulsing improvements that are described in detail in the paper. At the same time, the facility in which it was installed has also been extensively upgraded, first by adding space for optical and interferometric diagnostics, and more recently by adding a containment chamber to prevent the environmental dispersal of hazardous and radioactive materials. The containment addition also further expands space for new non-radiographic diagnostics. The new Contained Firing Facility is still in the process of activation. At the same time, FXR is continuing to undergo modifications aimed primarily at further increasing radiographic resolution and sensitivity, and at improving double-pulsed performance
High-voltage many-pulses generator with inductive energy store and fuse
Kovalev, V.P.; Diyankov, V.S.; Kormilitsin, A.I.; Lavrent'ev, B.N.
1996-01-01
The high-voltage generator with inductive energy store and fuses as opening switch that generate series of powerful pulses is considered. This generator differs from the ordinary generator with inductive store by the cross-section of the series copper wires. The parameters of the wires are chosen based on empirical relations. The generation principle was tested on the two high-voltage generators with characteristic impedance 2.2 ohm, 4 ohm and with output voltages of 140 kV and 420 kV, respectively. Copper wires 0.1 to 0.23 mm in diameter were used. Series of 2 to 5 pulses of 100 to 300 ns duration, 400 to 1000 kV amplitude and 1 - 10 GW power were obtained. Pulses can be both the same and different. Two successive bremsstrahlung radiation pulses were obtain on the EMIR-M and IGUR-3 devices. Series power megavolt pulses can be generated with a power exceeding 10 11 W, pulse duration of 10 -3 to 10 -6 s, and time interval between them 10 -7 to 10 -5 s. (author). 4 figs., 2 refs
High-voltage many-pulses generator with inductive energy store and fuse
Kovalev, V P; Diyankov, V S; Kormilitsin, A I; Lavrent` ev, B N [All-Russian Research Inst. of Technical Physics, Snezhinsk (Russian Federation)
1997-12-31
The high-voltage generator with inductive energy store and fuses as opening switch that generate series of powerful pulses is considered. This generator differs from the ordinary generator with inductive store by the cross-section of the series copper wires. The parameters of the wires are chosen based on empirical relations. The generation principle was tested on the two high-voltage generators with characteristic impedance 2.2 ohm, 4 ohm and with output voltages of 140 kV and 420 kV, respectively. Copper wires 0.1 to 0.23 mm in diameter were used. Series of 2 to 5 pulses of 100 to 300 ns duration, 400 to 1000 kV amplitude and 1 - 10 GW power were obtained. Pulses can be both the same and different. Two successive bremsstrahlung radiation pulses were obtain on the EMIR-M and IGUR-3 devices. Series power megavolt pulses can be generated with a power exceeding 10{sup 11} W, pulse duration of 10{sup -3} to 10{sup -6} s, and time interval between them 10{sup -7} to 10{sup -5} s. (author). 4 figs., 2 refs.
Low voltage RF MEMS variable capacitor with linear C-V response
Elshurafa, Amro M.
2012-07-23
An RF MEMS variable capacitor, fabricated in the PolyMUMPS process and tuned electrostatically, possessing a linear capacitance-voltage response is reported. The measured quality factor of the device was 17 at 1GHz, while the tuning range was 1.2:1 and was achieved at an actuation DC voltage of 8V only. Further, the linear regression coefficient was 0.98. The variable capacitor was created such that it has both vertical and horizontal capacitances present. As the top suspended plate moves towards the bottom fixed plate, the vertical capacitance increases whereas the horizontal capacitance decreases simultaneously such that the sum of the two capacitances yields a linear capacitance-voltage relation. © 2012 The Institution of Engineering and Technology.
Shvetsov, N. K., E-mail: elmash@em.ispu.ru [V. I. Lenin Ivanovo State Power University (Russian Federation)
2016-11-15
The results of calculations of the increase in losses in an induction motor with frequency control and different forms of the supply voltage are presented. The calculations were performed by an analytic method based on harmonic analysis of the supply voltage as well as numerical calculation of the electromagnetic processes by the finite-element method.
Modulation linearization of a frequency-modulated voltage controlled oscillator, part 3
Honnell, M. A.
1975-01-01
An analysis is presented for the voltage versus frequency characteristics of a varactor modulated VHF voltage controlled oscillator in which the frequency deviation is linearized by using the nonlinear characteristics of a field effect transistor as a signal amplifier. The equations developed are used to calculate the oscillator output frequency in terms of pertinent circuit parameters. It is shown that the nonlinearity exponent of the FET has a pronounced influence on frequency deviation linearity, whereas the junction exponent of the varactor controls total frequency deviation for a given input signal. A design example for a 250 MHz frequency modulated oscillator is presented.
Reduction of torque ripple in DTC induction motor drive with discrete voltage vectors
Rosić Marko
2014-01-01
Full Text Available This paper presents а practical implementation of direct torque control (DTC of an induction machine on MSK2812 DSP platform, and the analysis of possibilities for reduction of torque ripple. Basic theoretical background relating the DTC was primarily set and the obtained experimental results have been given. It is shown that the torque ripple can be reduced by adjusting the intensity of voltage vectors and by modification of hysteresis comparator, while the simplicity of the basic DTC algorithm has been maintained. [Projekat Ministarstva nauke Republike Srbije, br. TR33016
Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo
2009-04-01
In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.
Numerical simulation on beam breakup unstability of linear induction accelerator
Zhang Kaizhi; Wang Huacen; Lin Yuzheng
2003-01-01
A code is written to simulate BBU in induction linac according to theoretical analysis. The general form of evolution of BBU in induction linac is investigated at first, then the effect of related parameters on BBU is analyzed, for example, the alignment error, oscillation frequency of beam centroid, beam pulse shape and acceleration gradient. At last measures are put forward to damp beam breakup unstability (BBU)
Tiunov, V. V.
2018-02-01
The report provides results of the research related to the tubular linear induction motors’ application. The motors’ design features, a calculation model, a description of test specimens for mining and electric power industry are introduced. The most attention is given to the single-phase motors for high voltage switches drives with the usage of inexpensive standard single-phase transformers for motors’ power supply. The method of the motor’s parameters determination, when the motor is being fed from the transformer, working in the overload mode, was described, and the results of it practical usage were good enough for the engineering practice.
Kenne, Godpromesse [Laboratoire d' Automatique et d' Informatique Appliquee (LAIA), Departement de Genie Electrique, Universite de Dschang, B.P. 134 Bandjoun, Cameroun; Goma, Raphael; Lamnabhi-Lagarrigue, Francoise [Laboratoire des Signaux et Systemes (L2S), CNRS-SUPELEC, Universite Paris XI, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France); Nkwawo, Homere [Departement GEII, Universite Paris XIII, IUT Villetaneuse, 99 Avenue Jean Baptiste Clement, 93430 Villetaneuse (France); Arzande, Amir; Vannier, Jean Claude [Departement Energie, Ecole Superieure d' Electricite-SUPELEC, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France)
2010-09-15
In this paper, a simple improved direct feedback linearization design method for transient stability and voltage regulation of power systems is discussed. Starting with the classical direct feedback linearization technique currently applied to power systems, an adaptive nonlinear excitation control of synchronous generators is proposed, which is new and effective for engineering. The power angle and mechanical power input are not assumed to be available. The proposed method is based on a standard third-order model of a synchronous generator which requires only information about the physical available measurements of angular speed, active electric power and generator terminal voltage. Experimental results of a practical power system show that fast response, robustness, damping, steady-state and transient stability as well as voltage regulation are all achieved satisfactorily. (author)
Kumano, Teruhisa
As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.
Voltage and pace-capture mapping of linear ablation lesions overestimates chronic ablation gap size.
O'Neill, Louisa; Harrison, James; Chubb, Henry; Whitaker, John; Mukherjee, Rahul K; Bloch, Lars Ølgaard; Andersen, Niels Peter; Dam, Høgni; Jensen, Henrik K; Niederer, Steven; Wright, Matthew; O'Neill, Mark; Williams, Steven E
2018-04-26
Conducting gaps in lesion sets are a major reason for failure of ablation procedures. Voltage mapping and pace-capture have been proposed for intra-procedural identification of gaps. We aimed to compare gap size measured acutely and chronically post-ablation to macroscopic gap size in a porcine model. Intercaval linear ablation was performed in eight Göttingen minipigs with a deliberate gap of ∼5 mm left in the ablation line. Gap size was measured by interpolating ablation contact force values between ablation tags and thresholding at a low force cut-off of 5 g. Bipolar voltage mapping and pace-capture mapping along the length of the line were performed immediately, and at 2 months, post-ablation. Animals were euthanized and gap sizes were measured macroscopically. Voltage thresholds to define scar were determined by receiver operating characteristic analysis as voltage, pace-capture, and ablation contact force maps. All modalities overestimated chronic gap size, by 1.4 ± 2.0 mm (ablation contact force map), 5.1 ± 3.4 mm (pace-capture), and 9.5 ± 3.8 mm (voltage mapping). Error on ablation contact force map gap measurements were significantly less than for voltage mapping (P = 0.003, Tukey's multiple comparisons test). Chronically, voltage mapping and pace-capture mapping overestimated macroscopic gap size by 11.9 ± 3.7 and 9.8 ± 3.5 mm, respectively. Bipolar voltage and pace-capture mapping overestimate the size of chronic gap formation in linear ablation lesions. The most accurate estimation of chronic gap size was achieved by analysis of catheter-myocardium contact force during ablation.
Low voltage RF MEMS variable capacitor with linear C-V response
Elshurafa, Amro M.; Ho, Pak Hung; Salama, Khaled N.
2012-01-01
.2:1 and was achieved at an actuation DC voltage of 8V only. Further, the linear regression coefficient was 0.98. The variable capacitor was created such that it has both vertical and horizontal capacitances present. As the top suspended plate moves towards the bottom
Electric field control methods for foil coils in high-voltage linear actuators
Beek, van T.A.; Jansen, J.W.; Lomonova, E.A.
2015-01-01
This paper describes multiple electric field control methods for foil coils in high-voltage coreless linear actuators. The field control methods are evaluated using 2-D and 3-D boundary element methods. A comparison is presented between the field control methods and their ability to mitigate
Fully Integrated, Low Drop-Out Linear Voltage Regulator in 180 nm CMOS
Yosef-Hay, Yoni; Larsen, Dennis Øland; Llimos Muntal, Pere
2017-01-01
This paper presents a capacitor-free low dropout (LDO) linear regulator based on a dual loop topology. The regulator utilizes two feedback loops to satisfy the challenges of hearing aid devices, which include fast transient performance and small voltage spikes under rapid load-current changes...
Analysis of doubly-fed induction machine operating at motoring mode subjected to voltage sag
Navneet Kumar
2016-09-01
Full Text Available Variable Speed (VS Pumped Storage Plants (PSP equipped with large asynchronous (Doubly-Fed Induction machines are emerging now in hydropower applications. Motoring mode of operation of Doubly-Fed Induction Machine (DFIM is essential and techno-economical in this application due to: (1 its uniqueness in active power controllability, (2 bulk power handing capability with less rated power converters in rotor circuit, and (3 integrating Renewable Energy Sources (RES. This paper investigates the performance of two DFIMs at different power ratings (2.2 kW and 2 MW under voltage sag with different attribute. The test results are analyzed in terms of the peaks in torque, speed, power taken and transient currents in rotor and stator circuits. During sag, stable region for DFIM operation along with speed and stator side reactive power input control is also illustrated. The negative effects of voltage sag are briefly discussed. MATLAB simulation is validated with experimentation. The various observations during simulation and experimental analysis are also supported by the theoretical explanations.
Rana, K. P. S.; Kumar, Vineet; Prasad, Tapan
2018-02-01
Temperature to Frequency Converters (TFCs) are potential signal conditioning circuits (SCCs) usually employed in temperature measurements using thermistors. A NE/SE-566 based SCC has been recently used in several reported works as TFC. Application of NE/SE-566 based SCC requires a mechanism for finding the optimal values of SCC parameters yielding the optimal linearity and desired sensitivity performances. Two classical methods, namely, inflection point and three point have been employed for this task. In this work, the application of these two methods, on NE/SE-566 based SCC in TFC, is investigated in detail and the conditions for its effective usage are developed. Further, since these classical methods offer an approximate linearization of temperature and frequency relationship an application of a linear search based technique is proposed to further enhance the linearity. The implemented linear search method used results obtained from the above mentioned classical methods. The presented simulation studies, for three different industrial grade thermistors, revealed that the linearity enhancements of 21.7, 18.3 and 17.8% can be achieved over the inflection point method and 4.9, 4.7 and 4.7% over the three point method, for an input temperature range of 0-100 °C.
Kunwar Aditya
2016-11-01
Full Text Available The extended describing function (EDF is a well-known method for modelling resonant converters due to its high accuracy. However, it requires complex mathematical formulation effort. This paper presents a simplified non-linear mathematical model of series-series (SS compensated inductive power transfer (IPT system, considering zero-voltage switching in the inverter. This simplified mathematical model permits the user to derive the small-signal model using the EDF method, with less computational effort, while maintaining the accuracy of an actual physical model. The derived model has been verified using a frequency sweep method in PLECS. The small-signal model has been used to design the voltage loop controller for a SS compensated IPT system. The designed controller was implemented on a 3.6 kW experimental setup, to test its robustness.
Induction linear accelerators with high-Tc bulk superconductor lenses
Matsuzawa, Hidenori; Wada, Haruhisa; Mori, Satoshi; Yamamoto, Tadashi
1991-01-01
Solenoidal coils in a one-stage induction accelerator were replaced by a high-T c bulk superconductor lens (Supertron). The accelerator postaccelerated injected electron beams to ∼ 400 keV, ∼ 0.35 kA, and ∼ 10 ns of duration time. (author)
A low-voltage fully balanced CMFF transconductor with improved linearity
Calvo, B.; Celma, S.; Alegre, J. P.; Sanz, M. T.
2007-05-01
This paper presents a new low-voltage pseudo-differential continuous-time CMOS transconductor for wideband applications. The proposed cell is based on a feedforward cancellation of the input common-mode signal and keeps the input common mode voltage constant, while the transconductance is easily tunable through a continuous bias voltage. Linearity is preserved during the tuning process for a moderate range of transconductance values. Simulation results for a 0.35 μm CMOS design show a 1:2 G m tuning range with an almost constant bandwidth over 600 MHz. Total harmonic distortion figures are below -60 dB over the whole range at 10 MHz up to a 200 μA p-p differential output. The proposed cell consumes less than 1.2 mW from a single 2.0 V supply.
Longitudinal and radial MHD linear induction accelerator with hot conducting plasma core
Denno, K.
1985-01-01
Conceptual design of linear induction accelerator is presented using for the core continuum a highly conductive plasma with sustained pumping velocity. Karlovitz criterion of boundary theory is employed in the process of design
Effect of Frequency and Spatial-Harmonics on Rotary and Linear Induction Motor Characteristics
1972-03-01
A computer analysis is made of the effect of current and MMF airgap harmonics on the output characteristics of rotary and linear induction motors. The current harmonics accompanying thyristor-control operation are evaluated by Fourier analyzing the p...
Coreless Linear Induction Motor (LIM) for Space-borne Electro-magnetic Mass Driver Applications
National Aeronautics and Space Administration — Large scale linear induction motors use ferromagnetic cores, but at high speed these cores choke the system’s ability to transform electrical energy into mechanical...
MAGNETIC INDUCTION DISTRIBUTION IN A LINEAR SYNCHRONUS MOTOR WITH MAGNETIC SUSPENSION
D.I. Parkhomenko
2013-02-01
Full Text Available Results of computer simulation and experimental investigations of magnetic induction distribution in a coaxial linear synchronous motor with magnetic suspension are presented. The magnetic induction distribution has been studied both in the motor air gap and on the runner surface.
MOSFET-based high voltage double square-wave pulse generator with an inductive adder configuration
Zhao, Xin [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Qiaogen, E-mail: hvzhang@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Long, Jinghua [College of Physics, Shenzhen University, Shenzhen 518060 (China); Lei, Yunfei; Liu, Jinyuan [Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)
2015-09-01
This paper presents a fast MOSFET-based solid-state pulse generator for high voltage double square-wave pulses. The generator consists mainly of an inductive adder system stacked of 20 solid-state modules. Each of the modules has 18 power MOSFETs in parallel, which are triggered by individual drive circuits; these drive circuits themselves are synchronously triggered by a signal from avalanche transistors. Our experiments demonstrate that the output pulses with amplitude of 8.1 kV and peak current of about 405 A are available at a load impedance of 20 Ω. The pulse has a double square-wave form with a rise and fall time of 40 ns and 26 ns, respectively and bottom flatness better than 12%. The interval time of the double square-wave pulses can be adjustable by varying the interval time of the trigger pulses.
''SensArray'' voltage sensor analysis in an inductively coupled plasma
Titus, M. J.; Hsu, C. C.; Graves, D. B.
2010-01-01
A commercially manufactured PlasmaVolt sensor wafer was studied in an inductively coupled plasma reactor in an effort to validate sensor measurements. A pure Ar plasma at various powers (25-420 W), for a range of pressures (10-80 mT), and bias voltages (0-250 V) was utilized. A numerical sheath simulation was simultaneously developed in order to interpret experimental results. It was found that PlasmaVolt sensor measurements are proportional to the rf-current through the sheath. Under conditions such that the sheath impedance is dominantly capacitive, sensor measurements follow a scaling law derived from the inhomogeneous sheath model of Lieberman and Lichtenberg, [Principles of Plasma Discharges and Materials Processing (Wiley, New York, 2005)]. Under these conditions, sensor measurements are proportional to the square root of the plasma density at the plasma-sheath interface, the one-fourth root of the electron temperature, and the one-fourth root of the rf bias voltage. When the sheath impedance becomes increasingly resistive, the sensor measurements deviate from the scaling law and tend to be directly proportional to the plasma density. The measurements and numerical sheath simulation demonstrate the scaling behavior as a function of changing sheath impedance for various plasma conditions.
Yao, J.; Li, H.; Liao, Y.
2008-01-01
The paper presents to develop a new control strategy of limiting the dc-link voltage fluctuation for a back-to-back pulsewidth modulation converter in a doubly fed induction generator (DFIG) for wind turbine systems. The reasons of dc-link voltage fluctuation are analyzed. An improved control...... strategy with the instantaneous rotor power feedback is proposed to limit the fluctuation range of the dc-link voltage. An experimental rig is set up to valid the proposed strategy, and the dynamic performances of the DFIG are compared with the traditional control method under a constant grid voltage....... Furthermore, the capabilities of keeping the dc-link voltage stable are also compared in the ride-through control of DFIG during a three-phase grid fault, by using a developed 2 MW DFIG wind power system model. Both the experimental and simulation results have shown that the proposed control strategy is more...
Beam control in the ETA-II linear induction accelerator
Chen, Y.J.
1992-01-01
Corkscrew beam motion is caused by chromatic aberration and misalignment of a focusing system. We have taken some measures to control the corkscrew motion on the ETA-II induction accelerator. To minimize chromatic aberration, we have developed an energy compensation scheme which reduces energy sweep and differential phase advance within a beam pulse. To minimize the misalignment errors, we have developed a time-independent steering algorithm which minimizes the observed corkscrew amplitude averaged over the beam pulse. The steering algorithm can be used even if the monitor spacing is much greater than the system's cyclotron wavelength and the corkscrew motion caused by a given misaligned magnet is fully developed, i.e., the relative phase advance is greater than 2π. (Author) 5 figs., 11 refs
WANG Qing-shan
2017-06-01
Full Text Available In view of the difficulties on technology of rotor chute in high voltage induction motor，the desig method adopted stator chute structure is put forward． The mathematical model of three dimensional nonlinear transient field for solving stator chute in high voltage induction motor is set up． Through the three dimensional entity model of motor，three dimensional finite element method based on T，ψ － ψ electromagnetic potential is adopted for the analysis and calculation of stator chute in high voltage induction motor under rated condition． The distributions long axial of fundamental wave magnetic field and tooth harmonic wave magnetic field are analyzed after stator chute，and the weakening effects on main tooth harmonic magnetic field are researched． Further more，the comparison analysis of main performance parameters of chute and straight slot is carried out under rated condition． The results show that the electrical performance of stator chute is better than that of straight slot in high voltage induction motor，and the tooth harmonic has been sharply decreased
Klíma, J.; Chomát, Miroslav; Schreier, Luděk
2008-01-01
Roč. 2, č. 6 (2008), s. 341-352 ISSN 1751-8660 R&D Projects: GA ČR GA102/08/0424 Institutional research plan: CEZ:AV0Z20570509 Keywords : DC-link voltage pulsations * torque ripple * induction motor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.660, year: 2008
An axisymmetrical non-linear finite element model for induction heating in injection molding tools
Guerrier, Patrick; Nielsen, Kaspar Kirstein; Menotti, Stefano
2016-01-01
To analyze the heating and cooling phase of an induction heated injection molding tool accurately, the temperature dependent magnetic properties, namely the non-linear B-H curves, need to be accounted for in an induction heating simulation. Hence, a finite element model has been developed......, including the non-linear temperature dependent magnetic data described by a three-parameter modified Frohlich equation fitted to the magnetic saturation curve, and solved with an iterative procedure. The numerical calculations are compared with experiments conducted with two types of induction coils, built...... in to the injection molding tool. The model shows very good agreement with the experimental temperature measurements. It is also shown that the non-linearity can be used without the temperature dependency in some cases, and a proposed method is presented of how to estimate an effective linear permeability to use...
Linear induction accelerator requirements for ion fast ignition
Logan, G.
1998-01-01
induction linacs, the purpose of this memo is to explore possible new features and characteristic parameters that induction linacs would need to meet the stringent requirements for beam quality and compression (sufficiently low longitudinal and transverse thermal spread) for ion driven fast ignition. Separately, Ed Lee at LBNL is looking at heavy-ion synchrotrons to meet similar fast ignition requirements. Parameters relating to cost (e.g, total beam-line length and transport quads, total core volt-seconds and power switching) have to be considered in addition to meeting the challenging beam quality requirements for fast ignition compared to conventional HIF. The aim of this preliminary study is to motivate, after critical debate, taking a next step to do more detailed designs, particle simulations, and experimental tests of the most critical accelerator elements and focusing optics, to further assess the feasibility of ion-driven fast ignition
Development of three channel linear bipolar high voltage amplifier (±2 KV) for electrostatic steerer
Rajesh Kumar; Mukesh Kumar; Suman, S.K.; Safvan, C.P.; Mandal, A.
2011-01-01
Electrostatic steerers and scanners are planned for low energy ion beam facilities at IUAC to steer and scan the ion beam on target. The power supplies for electrostatic steerers are high voltage bipolar DC amplifiers and for scanners are bipolar AC amplifiers. To fulfil the requirements a common unit has been designed and assembled for AC and DC applications. It can be used with electrostatic devices in scanning, steering and sweeping of low energy ion beams at high frequencies to attain uniform implantation. The unit consist of three independent limited bandwidth high voltage, linear bipolar amplifiers (for X-axis, Y-axis and Y1-dog leg plates). The unit has been provided with both local and remote control. (author)
Linearity optimizations of analog ring resonator modulators through bias voltage adjustments
Hosseinzadeh, Arash; Middlebrook, Christopher T.
2018-03-01
The linearity of ring resonator modulator (RRM) in microwave photonic links is studied in terms of instantaneous bandwidth, fabrication tolerances, and operational bandwidth. A proposed bias voltage adjustment method is shown to maximize spur-free dynamic range (SFDR) at instantaneous bandwidths required by microwave photonic link (MPL) applications while also mitigating RRM fabrication tolerances effects. The proposed bias voltage adjustment method shows RRM SFDR improvement of ∼5.8 dB versus common Mach-Zehnder modulators at 500 MHz instantaneous bandwidth. Analyzing operational bandwidth effects on SFDR shows RRMs can be promising electro-optic modulators for MPL applications which require high operational frequencies while in a limited bandwidth such as radio-over-fiber 60 GHz wireless network access.
Gaubas, E; Ceponis, T; Kusakovskij, J
2011-08-01
A technique for the combined measurement of barrier capacitance and spreading resistance profiles using a linearly increasing voltage pulse is presented. The technique is based on the measurement and analysis of current transients, due to the barrier and diffusion capacitance, and the spreading resistance, between a needle probe and sample. To control the impact of deep traps in the barrier capacitance, a steady state bias illumination with infrared light was employed. Measurements of the spreading resistance and barrier capacitance profiles using a stepwise positioned probe on cross sectioned silicon pin diodes and pnp structures are presented.
Voltage splay modes and enhanced phase locking in a modified linear Josephson array
Harris, E. B.; Garland, J. C.
1997-02-01
We analyze a modified linear Josephson-junction array in which additional unbiased junctions are used to greatly enhance phase locking. This geometry exhibits strong correlated behavior, with an external magnetic field tuning the voltage splay angle between adjacent Josephson oscillators. The array displays a coherent in-phase mode for f=, where f is the magnetic frustration, while for 0tolerant of critical current disorder approaching 100%. The stability of the array has also been studied by computing Floquet exponents. These exponents are found to be negative for all array lengths, with a 1/N2 dependence, N being the number of series-connected junctions.
M. S. MANNA
2011-12-01
Full Text Available The development of electromagnetic devices as machines, transformers, heating devices confronts the engineers with several problems. For the design of an optimized geometry and the prediction of the operational behaviour an accurate knowledge of the dependencies of the field quantities inside the magnetic circuits is necessary. This paper provides the eddy current and core flux density distribution analysis in linear induction motor. Magnetic flux in the air gap of the Linear Induction Motor (LIM is reduced to various losses such as end effects, fringes, effect, skin effects etc. The finite element based software package COMSOL Multiphysics Inc. USA is used to get the reliable and accurate computational results for optimization the performance of Linear Induction Motor (LIM. The geometrical characteristics of LIM are varied to find the optimal point of thrust and minimum flux leakage during static and dynamic conditions.
Loss of Excitation Detection in Doubly Fed Induction Generator by Voltage and Reactive Power Rate
M. J. Abbasi
2016-12-01
Full Text Available The doubly fed induction generator (DFIG is one of the most popular technologies used in wind power systems. With the growing use of DFIGs and increasing power system dependence on them in recent years, protecting of these generators against internal faults is more considered. Loss of excitation (LOE event is among the most frequent failures in electric generators. However, LOE detection studies heretofore were usually confined to synchronous generators. Common LOE detection methods are based on impedance trajectory which makes the system slow and also prone to interpret a stable power swing (SPS as a LOE fault. This paper suggests a new method to detect the LOE based on the measured variables from the DFIG terminal. In this combined method for LOE detection, the rate of change of both the terminal voltage and the output reactive power are utilized and for SPS detection, the fast Fourier transform (FFT analysis of the output instantaneous active power has been used. The performance of the proposed method was evaluated using Matlab/Simulink interface for various power capacities and operating conditions. The results proved the method's quickness, simplicity and security.
On the modelling of linear-assisted DC-DC voltage regulators for photovoltaic solar energy systems
Martínez-García, Herminio; García-Vílchez, Encarna
2017-11-01
This paper shows the modelling of linear-assisted or hybrid (linear & switching) DC/DC voltage regulators. In this kind of regulators, an auxiliary linear regulator is used, which objective is to cancel the ripple at the output voltage and provide fast responses for load variations. On the other hand, a switching DC/DC converter, connected in parallel with the linear regulator, allows to supply almost the whole output current demanded by the load. The objective of this topology is to take advantage of the suitable regulation characteristics that series linear voltage regulators have, but almost achieving the high efficiency that switching DC/DC converters provide. Linear-assisted DC/DC regulators are feedback systems with potential instability. Therefore, their modelling is mandatory in order to obtain design guidelines and assure stability of the implemented power supply system.
Kirillov, Igor R.; Obukhov, Denis M.; Ogorodnikov, Anatoly P.; Araseki, Hideo
2004-01-01
The paper describes and compares three computer codes that are able to estimate the double-supply-frequency (DSF) pulsations in annular linear induction pumps (ALIPs). The DSF pulsations are the result of interaction of the magnetic field and induced in liquid metal currents both changing with supply-frequency. They may be of some concern for electromagnetic pumps (EMP) exploitation and need to be evaluated at their design. The results of computer simulation are compared with experimental ones for annular linear induction pump ALIP-1
The Design of the Annular Linear Induction EM Pump with a Sodium Flowrate of 35 kg/sec
Kim, Hee Reyoung; Lee, Tae Ho; Lee, Yong Bum
2010-01-01
Generally, an electromagnetic (EM) pump has been employed to circulate liquid metal with a high electrical conductivity by the electromagnetic force (Lorentz force) which is the cross product of the magnetic field and its perpendicular current. Therefore, an EM pump has its advantages over a mechanical pump such as no noise, no rotating parts, and its simplicity. Actually, it can be used for the Sodium Fast Reactor (SFR) which uses liquid sodium with a high electrical conductivity as a coolant. In the present study, the annular linear induction EM pump with a flowrate of 2,265 L/min and a head of 4 bar is designed by using an electrical equivalent circuit method which is applied to linear induction machines. The designed pump will be used for the verification of the elements, which are IHX, AHX and DHX, in the component performance test sodium loop for the sodium thermo-hydraulic experimental facility. The pump is manufactured and fabricated to meet the requirements of the material and a functioning in high temperature-sodium environments. The P-Q characteristic is theoretically calculated on the designed pump according to the input currents and voltage
An analysis of the electromagnetic field in multi-polar linear induction system
Chervenkova, Todorka; Chervenkov, Atanas
2002-01-01
In this paper a new method for determination of the electromagnetic field vectors in a multi-polar linear induction system (LIS) is described. The analysis of the electromagnetic field has been done by four dimensional electromagnetic potentials in conjunction with theory of the magnetic loops . The electromagnetic field vectors are determined in the Minkovski's space as elements of the Maxwell's tensor. The results obtained are compared with those got from the analysis made by the finite elements method (FEM).With the method represented in this paper one can determine the electromagnetic field vectors in the multi-polar linear induction system using four-dimensional potential. A priority of this method is the obtaining of analytical results for the electromagnetic field vectors. These results are also valid for linear media. The dependencies are valid also at high speeds of movement. The results of the investigated linear induction system are comparable to those got by the finite elements method. The investigations may be continued in the determination of other characteristics such as drag force, levitation force, etc. The method proposed in this paper for an analysis of linear induction system can be used for optimization calculations. (Author)
Proposed inductive voltage adder based accelerator concepts for the second axis of DARHT
Smith, D.L.; Johnson, D.L.; Boyes, J.D.
1997-01-01
As participants in the Technology Options Study for the second axis of the Dual Axis Radiographic HydroTest (DARHT) facility located at Los Alamos National Laboratories, the authors have considered several accelerator concepts based on the Inductive Voltage Adder (IVA) technology that is being used successfully at Sandia on the SABRE and HERMES-III facilities. The challenging accelerator design requirements for the IVA approach include: ≥12-MeV beam energy; ∼60-ns electrical pulse width; ≤40-kA electron beam current; ∼1-mm diameter e-beam; four pulses on the same axis or as close as possible to that axis; and an architecture that fits within the existing building envelope. To satisfy these requirements the IVA concepts take a modular approach. The basic idea is built upon a conservative design for eight ferromagnetically isolated 2-MV cavities that are driven by two 3 to 4-Ω water dielectric pulse forming lines (PFLs) synchronized with laser triggered gas switches. The 100-Ω vacuum magnetically insulated transmission line (MITL) would taper to a needle cathode that produces the electron beam(s). After considering many concepts the authors narrowed their study to the following options: (A) Four independent single pulse drivers powering four single pulse diodes; (B) Four series adders with interleaved cavities feeding a common MITL and diode; (C) Four stages of series PFLs, isolated from each other by triggered spark gap switches, with single-point feeds to a common adder, MITL, and diode; and (D) Isolated PFLs with multiple-feeds to a common adder using spark gap switches in combination with saturable magnetic cores to isolate the non-energized lines. The authors will discuss these options in greater detail identifying the challenges and risks associated with each
The design of the accelerating gaps for the linear induction accelerator RADLAC II
Shope, S.L.; Mazarakis, M.G.; Miller, R.B.; Poukey, J.W.
1987-01-01
In high current (50 kA) linear induction accelerators, the accelerating gaps can excite large radial oscillations. A gap was designed that minimized the radial oscillations and reduced potential depressions. The envelope equation predicted radial oscillation amplitudes of 1 mm which agreed with experimental measurements
Direct and quadrature inductances measurement of the permanent magnetic linear synchronous machines
Li Liyi [Electrical Engineering Dept./Harbin Institute of Technology, Harbin 150000 (China); Hong Junjie, E-mail: wizard0663@126.co [School of Engineering/Sun Yat-Sen University, Guangzhou 510006 (China); Wu Hongxing; Kou Baoquan; Liu Rizhong [Electrical Engineering Dept./Harbin Institute of Technology, Harbin 150000 (China)
2011-05-15
Research highlights: {yields} The d- and q-axis inductances are derived theoretically. {yields} The new measurement principle of the d- and q-axis inductances is analyzed. {yields} A corresponding measuring circuit is developed. {yields} Measurement results match those of the FEM well. -- Abstract: Permanent magnetic linear synchronous machines (PMLSMs) are playing a more important role either in transportation systems or magnetic launch systems, for the excellent advantages. It is indispensable to high performance controllers that some machine parameters are known such as the direct axis (d-axis) and quadrature axis (q-axis) inductances. In this paper, self and mutual inductances of the three-phase winding are deduced by basic electric machinery theory, and the measured inductances are analyzed since the mutual inductances and the corresponding terminals among three-phase windings are changing as different phase winding is concerned. The d- and q-axis inductances are measured with the designed circuit, and the experimental measurement method is validated by the comparison between the experimental and finite element method (FEM) results.
Direct and quadrature inductances measurement of the permanent magnetic linear synchronous machines
Li Liyi; Hong Junjie; Wu Hongxing; Kou Baoquan; Liu Rizhong
2011-01-01
Research highlights: → The d- and q-axis inductances are derived theoretically. → The new measurement principle of the d- and q-axis inductances is analyzed. → A corresponding measuring circuit is developed. → Measurement results match those of the FEM well. -- Abstract: Permanent magnetic linear synchronous machines (PMLSMs) are playing a more important role either in transportation systems or magnetic launch systems, for the excellent advantages. It is indispensable to high performance controllers that some machine parameters are known such as the direct axis (d-axis) and quadrature axis (q-axis) inductances. In this paper, self and mutual inductances of the three-phase winding are deduced by basic electric machinery theory, and the measured inductances are analyzed since the mutual inductances and the corresponding terminals among three-phase windings are changing as different phase winding is concerned. The d- and q-axis inductances are measured with the designed circuit, and the experimental measurement method is validated by the comparison between the experimental and finite element method (FEM) results.
The use of charge extraction by linearly increasing voltage in polar organic light-emitting diodes
Züfle, Simon; Altazin, Stéphane; Hofmann, Alexander; Jäger, Lars; Neukom, Martin T.; Schmidt, Tobias D.; Brütting, Wolfgang; Ruhstaller, Beat
2017-05-01
We demonstrate the application of the CELIV (charge carrier extraction by linearly increasing voltage) technique to bilayer organic light-emitting devices (OLEDs) in order to selectively determine the hole mobility in N,N0-bis(1-naphthyl)-N,N0-diphenyl-1,10-biphenyl-4,40-diamine (α-NPD). In the CELIV technique, mobile charges in the active layer are extracted by applying a negative voltage ramp, leading to a peak superimposed to the measured displacement current whose temporal position is related to the charge carrier mobility. In fully operating devices, however, bipolar carrier transport and recombination complicate the analysis of CELIV transients as well as the assignment of the extracted mobility value to one charge carrier species. This has motivated a new approach of fabricating dedicated metal-insulator-semiconductor (MIS) devices, where the extraction current contains signatures of only one charge carrier type. In this work, we show that the MIS-CELIV concept can be employed in bilayer polar OLEDs as well, which are easy to fabricate using most common electron transport layers (ETLs), like Tris-(8-hydroxyquinoline)aluminum (Alq3). Due to the macroscopic polarization of the ETL, holes are already injected into the hole transport layer below the built-in voltage and accumulate at the internal interface with the ETL. This way, by a standard CELIV experiment only holes will be extracted, allowing us to determine their mobility. The approach can be established as a powerful way of selectively measuring charge mobilities in new materials in a standard device configuration.
Fernandez, Fernando R.; Malerba, Paola; White, John A.
2015-01-01
The presence of voltage fluctuations arising from synaptic activity is a critical component in models of gain control, neuronal output gating, and spike rate coding. The degree to which individual neuronal input-output functions are modulated by voltage fluctuations, however, is not well established across different cortical areas. Additionally, the extent and mechanisms of input-output modulation through fluctuations have been explored largely in simplified models of spike generation, and with limited consideration for the role of non-linear and voltage-dependent membrane properties. To address these issues, we studied fluctuation-based modulation of input-output responses in medial entorhinal cortical (MEC) stellate cells of rats, which express strong sub-threshold non-linear membrane properties. Using in vitro recordings, dynamic clamp and modeling, we show that the modulation of input-output responses by random voltage fluctuations in stellate cells is significantly limited. In stellate cells, a voltage-dependent increase in membrane resistance at sub-threshold voltages mediated by Na+ conductance activation limits the ability of fluctuations to elicit spikes. Similarly, in exponential leaky integrate-and-fire models using a shallow voltage-dependence for the exponential term that matches stellate cell membrane properties, a low degree of fluctuation-based modulation of input-output responses can be attained. These results demonstrate that fluctuation-based modulation of input-output responses is not a universal feature of neurons and can be significantly limited by subthreshold voltage-gated conductances. PMID:25909971
Wang Fa-Qiang; Ma Xi-Kui
2013-01-01
The effects of both the switching frequency and the leakage inductance on the slow-scale stability in a voltage controlled flyback converter are investigated in this paper. Firstly, the system description and its mathematical model are presented. Then, the improved averaged model, which covers both the switching frequency and the leakage inductance, is established, and the effects of these two parameters on the slow-scale stability in the system are analyzed. It is found that the occurrence of Hopf bifurcation in the system is the main reason for losing its slow-scale stability and both the switching frequency and the leakage inductance have an important effect on this slow-scale stability. Finally, the effectiveness of the improved averaged model and that of the corresponding theoretical analysis are confirmed by the simulation results and the experimental results. (general)
Voltage splay modes and enhanced phase locking in a modified linear Josephson array
Harris, E.B.; Garland, J.C.
1997-01-01
We analyze a modified linear Josephson-junction array in which additional unbiased junctions are used to greatly enhance phase locking. This geometry exhibits strong correlated behavior, with an external magnetic field tuning the voltage splay angle between adjacent Josephson oscillators. The array displays a coherent in-phase mode for f=(1)/(2), where f is the magnetic frustration, while for 0 p (f)=2aV dc /Φ 0 (1-2f). The locked splay modes are found to be tolerant of critical current disorder approaching 100%. The stability of the array has also been studied by computing Floquet exponents. These exponents are found to be negative for all array lengths, with a 1/N 2 dependence, N being the number of series-connected junctions. copyright 1996 The American Physical Society
A Study on Energy Saving of Single Phase Induction Motor By Voltage Control
Bae, Jong Moon [Pusan College of Information Technolgy, Pusan (Korea); Kim, Joon Hong [Dong Myong College, Pusan (Korea)
2001-06-01
This paper describes a simple effective method for energy saving of AC motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, TRIAC voltage control characteristics. The parameters of simplified voltage-current pattern can be determined approximately and reliably from the rated voltage and current of the motor. Experiments are focused on a single phase capacitor motor, the optimal energy saving are proved by proposed method. (author). 8 refs., 15 figs.
Method for the mechanical axis alignment of the linear induction accelerator
Li Hong; China Academy of Engineering Physics, Mianyang; Yao Jin; Liu Yunlong; Zhang Linwen; Deng Jianjun
2004-01-01
Accurate mechanical axis alignment is a basic requirement for assembling a linear induction accelerator (LIA). The total length of an LIA is usually over thirty or fifty meters, and it consists of many induction cells. By using a laser tracker a new method of mechanical axis alignment for LIA is established to achieve the high accuracy. This paper introduces the method and gives implementation step and point position measure errors of the mechanical axis alignment. During the alignment process a 55 m-long alignment control survey net is built, and the theoretic revision of the coordinate of the control survey net is presented. (authors)
Optimization design of the main switch in 12 MeV linear induction accelerator
Li Xin; Wang Jinsheng; Ding Hensong; Ye Yi
2004-01-01
A method for optimization design of the main switch (using in 12 MeV linear induction accelerator) was introduced. The switch's inductance was decreased from 63.7 nH to 35 nH by optimizing the configuration of the main switch and the size of the electric poles so that the accelerating cavity can get a better rising time of 27 ns. The accelerator's performance can be effectively improved through this method, the feasibility of the method is also proved by testing
Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar
2018-01-01
Open End Winding Induction Motors (OEWIM) are popular for electric vehicles, ship propulsion applications due to less DC link voltage. Electric vehicles, ship propulsions require ripple free torque. In this article, an enhanced three-level voltage switching state scheme for direct torque controlled OEWIM drive is implemented to reduce torque and flux ripples. The limitations of conventional Direct Torque Control (DTC) are: possible problems during low speeds and starting, it operates with variable switching frequency due to hysteresis controllers and produces higher torque and flux ripple. The proposed DTC scheme can abate the problems of conventional DTC with an enhanced voltage switching state scheme. The three-level inversion was obtained by operating inverters with equal DC-link voltages and it produces 18 voltage space vectors. These 18 vectors are divided into low and high frequencies of operation based on rotor speed. The hardware results prove the validity of proposed DTC scheme during steady-state and transients. From simulation and experimental results, proposed DTC scheme gives less torque and flux ripples on comparison to two-level DTC. The proposed DTC is implemented using dSPACE DS-1104 control board interface with MATLAB/SIMULINK-RTI model.
Kiani, Morgan Mozhgan
Inherent difficulties in management of electric power in the presence of an increasing demand for more energy, non-conventional loads such as digital appliances, and non-sustainable imported fossil fuels has initiated a multi-folded effort by many countries to restructure the way electric energy is generated, dispatched, and consumed. Smart power grid is the manifestation of many technologies that would eventually transforms the existing power grid into a more flexible, fault resilient, and intelligent system. Integration of distributed renewable energy sources plays a central role in successful implementation of this transformation. Among the renewable options, wind energy harvesting offers superior engineering and economical incentives with minimal environmental impacts. Doubly fed induction generators (DFIG) have turned into a serious contender for wind energy generators due to their flexibility in control of active and reactive power with minimal silicon loss. Significant presence of voltage unbalance and system harmonics in finite inertia transmission lines can potentially undermine the reliability of these wind generators. The present dissertation has investigated the impacts of system unbalances and harmonics on the performance of the DFIG. Our investigation indicates that these effects can result in an undesirable undulation in the rotor shaft which can potentially invoke mechanical resonance, thereby causing catastrophic damages to the installations and the power grid. In order to remedy the above issue, a control solution for real time monitoring of the system unbalance and optimal excitation of the three phase rotor currents in a DFIG is offered. The optimal rotor currents will create appropriate components of the magneto-motive force in the airgap that will actively compensate the undesirable magnetic field originated by the stator windings. Due to the iterative nature of the optimization procedure, field reconstruction method has been incorporated
Voltage protection scheme for MG sets used to drive inductive energy storage systems
Campen, G.L.; Easter, R.B.
1977-01-01
A recent tokamak proposal at ORNL called for MG (motor-generator) sets to drive the ohmic heating (OH] coil, which was to be subjected to 20 kV immediately after coil charge-up to initiate the experiment. Since most rotating machinery is inherently low voltage, including the machines available at ORNL, a mechanism was necessary to isolate the generators from the high voltage portions of the circuit before the appearance of this voltage. It is not the expected 20 kV at the coil that causes difficulty, because the main interrupting switch handles this. The voltage induced in the armature due to di/dt and the possibility of faults are the greatest causes for concern and are responsible for the complexity of the voltage protection scheme, which must accommodate any possible combination of fault time and location. Such a protection scheme is presented in this paper
Optimum design for 12 MeV linear induction accelerator diode
Yu Haijun; Shi Jinshui; Li Qin; He Guorong; Ma Bing; Wang Jingsheng; Wang Liping
2001-01-01
A series of optimization designs of electron diode in 12 Mev linear induction accelerator are studied by using numerical simulation code MAGIC and experiment method in order to improve the electron beam quality. MAGIC code solves the Maxwell equations in the presence of charged particle, electron field distribution on cathode surface which influences electron emission is given, the optimum diode is obtained by comparing the results of experiment in 12 MeV linear induction accelerator. The author also gives SEM analysis and experiment comparison of velvet emission. Finally, emitted current I e = 8.52 kA, beam current I 8 ≥ 3.0 kA, targeted current I 0 ≥ 2.30 kA with optimum diode are obtained
Dynamic diagnostics of moving ferromagnetic material with the linear induction motor
Szewczyk Krzysztof; Walasek Tomasz
2017-01-01
The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were perfor...
Mathematical models of flat linear induction motors used in mining drives
Tall, M
1984-01-01
Design parameters are calculated for electric flat linear induction motors, widely employed in the coal and ore mining industries in Poland. A mathematical model of this motor with a single-layer ferromagnetic secondary part is presented. A three-dimensional electromagnetic field analysis is carried out, taking relative magnetic permeability variation, discrete winding distribution, influence of armature grooving and pulsating field influence into account. A computer calculation algorithm is proposed for determining motor characteristics. 17 refs.
Hasegawa, Chihiro; Duffull, Stephen B
2018-02-01
Pharmacokinetic-pharmacodynamic systems are often expressed with nonlinear ordinary differential equations (ODEs). While there are numerous methods to solve such ODEs these methods generally rely on time-stepping solutions (e.g. Runge-Kutta) which need to be matched to the characteristics of the problem at hand. The primary aim of this study was to explore the performance of an inductive approximation which iteratively converts nonlinear ODEs to linear time-varying systems which can then be solved algebraically or numerically. The inductive approximation is applied to three examples, a simple nonlinear pharmacokinetic model with Michaelis-Menten elimination (E1), an integrated glucose-insulin model and an HIV viral load model with recursive feedback systems (E2 and E3, respectively). The secondary aim of this study was to explore the potential advantages of analytically solving linearized ODEs with two examples, again E3 with stiff differential equations and a turnover model of luteinizing hormone with a surge function (E4). The inductive linearization coupled with a matrix exponential solution provided accurate predictions for all examples with comparable solution time to the matched time-stepping solutions for nonlinear ODEs. The time-stepping solutions however did not perform well for E4, particularly when the surge was approximated by a square wave. In circumstances when either a linear ODE is particularly desirable or the uncertainty in matching the integrator to the ODE system is of potential risk, then the inductive approximation method coupled with an analytical integration method would be an appropriate alternative.
THE STUDY OF SELF-BALANCED POTATO SORTING MACHINE WITH LINEAR INDUCTION DRIVE
Linenko A. V.; Baynazarov V. G.; Kamalov T. I.
2016-01-01
In the article we have considered the self-balanced potato sorting machine differing from existing designs of self-balanced potato sorting machines with an oscillatory electric drive. That drive uses a linear induction motor. As the counterbalancing device, the method of the duplicating mechanism is applied. The duplicating mechanism is a specular reflection of the main working body, and also participates in technological process. Its application in the drive of machine allows not only to inc...
Experimental and numerical analysis of behavior of electromagnetic annular linear induction pump
Goldsteins, Linards
2015-01-01
The research explores the issue of magnetohydrodynamic (MHD) instability in electromagnetic induction pumps with focus on the regimes of high slip Reynolds magnetic number (Rm s ) in Annular Linear Induction Pumps (ALIP) operating with liquid sodium. The context of the thesis is French GEN IV Sodium Fast Reactor research and development program for ASTRID in a framework of which the use of high discharge ALIP in the secondary cooling loops is being studied. CEA has designed, realized and will exploit PEMDYN facility, able to represent MHD instability in high discharge ALIP. In the thesis stability of an ideal ALIP is elaborated theoretically using linear stability analysis. Analysis revealed that strong amplification of perturbation is expected after convective stability threshold is reached. Theory is supported with numerical results and experiments reported in literature. Stable operation and stabilization technique operating with two frequencies in case of an ideal ALIP is discussed and necessary conditions derived. Detailed numerical models of flat linear induction pump (FLIP) taking into account effects of a real pump are developed. New technique of magnetic field measurements has been introduced and experimental results demonstrate a qualitative agreement with numerical models capturing all principal phenomena such as oscillation of magnetic field and perturbed velocity profiles. These results give significantly more profound insight in the phenomenon of MHD instability and can be used as a reference in further studies. (author) [fr
Low Voltage Electrolytic Capacitor Pulse Forming Inductive Network for Electric Weapons
Mays, Thomas A
2006-01-01
.... Pulsed alternators potentially have the same maintenance issues as other motor-generator sets, so a solid-state system would be desirable, but high voltage capacitor systems are not robust enough for the field...
Hinshelwood, D. D.; Schumer, J. W.; Allen, R. J.; Commisso, R. J.; Jackson, S. L.; Murphy, D. P.; Phipps, D.; Swanekamp, S. B.; Weber, B. V.; Ottinger, P. F.; Apruzese, J. P.; Cooperstein, G.; Young, F. C.
2011-01-01
A pinch-reflex ion diode is fielded on the pulsed-power machine Mercury (R. J. Allen, et al., 15th IEEE Intl. Pulsed Power Conf., Monterey, CA, 2005, p. 339), which has an inductive voltage adder (IVA) architecture and a magnetically insulated transmission line (MITL). Mercury is operated in positive polarity resulting in layered MITL flow as emitted electrons are born at a different potential in each of the adder cavities. The usual method for estimating the voltage by measuring the bound current in the cathode and anode of the MITL is not accurate with layered flow, and the interaction of the MITL flow with a pinched-beam ion diode load has not been studied previously. Other methods for determining the diode voltage are applied, ion diode performance is experimentally characterized and evaluated, and circuit and particle-in-cell (PIC) simulations are performed. Results indicate that the ion diode couples efficiently to the machine operating at a diode voltage of about 3.5 MV and a total current of about 325 kA, with an ion current of about 70 kA of which about 60 kA is proton current. It is also found that the layered flow impedance of the MITL is about half the vacuum impedance.
Zhan-Feng Song
2012-11-01
Full Text Available A novel control strategy is proposed in this paper for the rotor side converter (RSC of doubly-fed induction generator (DFIG-based wind power generation systems. It is supposed to enhance the low-voltage ride-through (LVRT capability of DFIGs during great-level grid voltage dips. The strategy consists of a proportional-resonant (PR controller and auxiliary PR controllers. The auxiliary controllers compensate the output voltage of the RSC in case of grid faults, thus limiting the rotor inrush current of DFIG and meeting the requirements of LVRT. Sequential-component decompositions of current are not required in the control system to improve the response of system. Since the resonant compensator is a double-side integrator, the auxiliary controllers can be simplified through coordinate transformation. The feasibility of the control strategy is validated by simulation on a 1.5 MW wind-turbine driven DFIG system. The impact of the RSC converter voltage rating on the LVRT capability of DFIG is investigated. Meanwhile, the influence of angular frequency detection and control parameters are also discussed. Compared with traditional vector control schemes based on PI current controllers, the presented control strategy effectively suppress rotor current and reduce oscillations of DFIG power and torque under grid faults.
New non-linear control strategy for non-isolated DC/DC converter with high voltage ratio
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.
New non-linear control strategy for non-isolated DC/DC converter with high voltage ratio
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)
Debruyne, Colin; Derammelaere, Stijn; Desmet, Jan; Vandevelde, Lieven
2012-01-01
Induction machines have nearly reached their maximal efficiency. In order to further increase the efficiency the use of permanent magnets in combination with the robust design of the induction machine is being extensively researched. These so-called line start permanent magnet machines have an increased efficiency in sine wave conditions in respect to standard induction machines, however the efficiency of these machines is less researched under distorted voltage conditions. This paper compare...
Induction of divalent cation permeability by heterologous expression of a voltage sensor domain.
Arima, Hiroki; Tsutsui, Hidekazu; Sakamoto, Ayako; Yoshida, Manabu; Okamura, Yasushi
2018-01-06
The voltage sensor domain (VSD) is a protein domain that confers sensitivity to membrane potential in voltage-gated ion channels as well as the voltage-sensing phosphatase. Although VSDs have long been considered to function as regulatory units acting on adjacent effectors, recent studies have revealed the existence of direct ion permeation paths in some mutated VSDs and in the voltage-gated proton channel. In this study, we show that calcium currents are evoked upon membrane hyperpolarization in cells expressing a VSD derived from an ascidian voltage-gated ion channel superfamily. Unlike the previously reported omega-pore in the Shaker K + channel and rNav1.4, mutations are not required. From electrophysiological experiments in heterologous expression systems, we found that the conductance is directly mediated by the VSD itself and is carried by both monovalent and divalent cations. This is the first report of divalent cation permeation through a VSD-like structure. Copyright © 2018 Elsevier B.V. All rights reserved.
Nondahl, T. A.; Richter, E.
1980-09-01
A design study of two types of single sided (with a passive rail) linear electric machine designs, namely homopolar linear synchronous machines (LSM's) and linear induction machines (LIM's), is described. It is assumed the machines provide tractive effort for several types of light rail vehicles and locomotives. These vehicles are wheel supported and require tractive powers ranging from 200 kW to 3735 kW and top speeds ranging from 112 km/hr to 400 km/hr. All designs are made according to specified magnetic and thermal criteria. The LSM advantages are a higher power factor, much greater restoring forces for track misalignments, and less track heating. The LIM advantages are no need to synchronize the excitation frequency precisely to vehicle speed, simpler machine construction, and a more easily anchored track structure. The relative weights of the two machine types vary with excitation frequency and speed; low frequencies and low speeds favor the LSM.
Lee, S. H.; Shulika, Olga.; Kim, K. N.; Yeom, G. Y.; Lee, J. K.
2004-09-01
As the technology of plasma processing progresses, there is a continuing demand for higher plasma density, uniformity over large areas and greater control over plasma parameters to optimize the processes of etching, deposition and surface treatment. Traditionally, the external planar ICP sources with low pressure high density plasma have limited scale-up capabilities due to its high impedance accompanied by the large antenna size. Also due to the cost and thickness of their dielectric material in order to generate uniform plasma. In this study the novel internal-type linear inductive antenna system (1,020mm¡¿830mm¡¿437mm) with permanent magnet arrays are investigated to improve both the plasma density and the uniformity of LAPS (Large Area Plasma Source) for FPD processing. Generally plasma discharges are enhanced because the inductance of the novel antenna (termed as the double comb antenna) is lower than that of the serpentine-type antenna and also the magnetic confinement of electron increases the power absorption efficiency. The uniformity is improved by reducing the standing wave effect. The total length of antenna is comparable to the driving rf wavelength to cause the plasma nonuniformity. To describe the discharge phenomenon we have developed a magnetized two-dimensional fluid simulation. This work was supported by National Research Laboratory (NRL) Program of the Korea Ministry of Science and Technology. [References] 1. J.K.Lee, Lin Meng, Y.K.Shin, H,J,Lee and T.H.Chung, ¡°Modeling and Simulation of a Large-Area Plasma Source¡±, Jpn. J. Appl. Phys. Vol.36(1997) pp. 5714-5723 2. S.E.Park, B.U.Cho, Y.J.Lee*, and G.Y.Yeom*, and J.K.Lee, ¡°The Characteristics of Large Area Processing Plasmas¡±, IEEE Trans. Plasma Sci., Vol.31 ,No.4(2003) pp. 628-637
Lim, Jong Hyeuk; Kim, Kyong Nam; Park, Jung Kyun; Yeom, Geun Young
2008-01-01
This study examined the effect of the antenna capacitance of an inductively coupled plasma (ICP) source, which was varied using an internal linear antenna, on the electrical and plasma characteristics of the ICP source. The inductive coupling at a given rf current increased with decreasing antenna capacitance. This was caused by a decrease in the inner copper diameter of the antenna made from coaxial copper/quartz tubing, which resulted in a higher plasma density and lower plasma potential. By decreasing the diameter of the copper tube from 25 to 10 mm, the plasma density of a plasma source size of 2750x2350 mm 2 was increased from approximately 8x10 10 /cm 3 to 1.5x10 11 /cm 3 at 15 mTorr Ar and 9 kW of rf power
Low-impedance internal linear inductive antenna for large-area flat panel display plasma processing
Kim, K.N.; Jung, S.J.; Lee, Y.J.; Yeom, G.Y.; Lee, S.H.; Lee, J.K.
2005-01-01
An internal-type linear inductive antenna, that is, a double-comb-type antenna, was developed for a large-area plasma source having the size of 1020 mmx830 mm, and high density plasmas on the order of 2.3x10 11 cm -3 were obtained with 15 mTorr Ar at 5000 W of inductive power with good plasma stability. This is higher than that for the conventional serpentine-type antenna, possibly due to the low impedance, resulting in high efficiency of power transfer for the double-comb antenna type. In addition, due to the remarkable reduction of the antenna length, a plasma uniformity of less than 8% was obtained within the substrate area of 880 mmx660 mm at 5000 W without having a standing-wave effect
New circuits high-voltage pulse generators with inductive-capacitive energy storage
Gordeev, V.S.; Myskov, G.A.
2001-01-01
The paper describes new electric circuits of multi-cascade generators based on stepped lines. The distinction of the presented circuits consists in initial storage of energy in electric and magnetic fields simultaneously. The circuit of each generator,relations of impedances,values of initial current and charge voltages are selected in such a manner that the whole of initially stored energy is concentrated at the generator output as a result of transient wave processes. In ideal case the energy is transferred with 100% efficiency to the resistive load where a rectangular voltage pulse is formed, whose duration is equals to the double electrical length of the individual cascade. At the same time there is realized a several time increase of output voltage as compared to the charge voltage of the generator. The use of the circuits proposed makes it possible to ensure a several time increase (as compared to the selection of the number of cascades) of the generator energy storage, pulse current and output electric power
Pencil-like mm-size electron beams produced with linear inductive voltage adders (LIVA)
Mazarakis, M.G.; Poukey, J.W.; Rovang, D.C.
1996-01-01
This paper presents design, analysis, and first results of the high brightness electron beam experiments currently under investigation at Sandia. Anticipated beam parameters are: energy 12 MeV, current 35-40 kA, rms radius 0.5 mm, pulse duration 40 ns FWHM. The accelerator is SABRE, a pulsed LIVA modified to higher impedance, and the electron source is a magnetically immersed foilless electron diode. 20 to 30 Tesla solenoidal magnets are required to insulate the diode and contain the beam to its extremely small sized (1 mm) envelope. These experiments are designed to push the technology to produce the highest possible electron current in a submillimeter radius beam. Design, numercial simulations, and first experimental results are presented
Pencil-like mm-size electron beams produced with Linear Inductive Voltage Adders (LIVA)
Mazarakis, M.G.; Poukey, J.W.; Rovang, D C.; Maenchen, J.E.; Cordova, S.R.; Menge, P.R.; Pepping, R.; Bennett, L.; Mikkelson, K.; Smith, D.L.; Halbleib, J.; Stygar, W.A.; Welch, D.R.
1996-01-01
We present the design, analysis, and first results of the high brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: energy 12 MeV, current 35-40 kA, rms radius 0.5 mm, and pulse duration 40 ns FWHM. The accelerator is SABRE, a pulsed LIVA modified to higher impedance, and the electron source is a magnetically immersed foilless electron diode. Twenty to thirty Tesla solenoidal magnets are required to insulate the diode and contain the beam to its extremely small sized (1 mm) envelope. These experiments are designed to push the technology to produce the highest possible electron current in a submillimeter radius beam. Design, numerical simulations, and first experimental results are presented. (author)
Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Sunaga, Akihiro; Tsujimura, Takuya; Matsuda, Yasuhiro; Mano, Toshiaki
2017-08-01
A bipolar voltage reflects a thick musculature where formation of a transmural lesion may be hard to achieve. The purpose of this study was to explore the association between local bipolar voltage and conduction gap in patients with persistent atrial fibrillation (AF) who underwent atrial roof or septal linear ablation. This prospective observational study included 42 and 36 consecutive patients with persistent AF who underwent roof or septal linear ablations, respectively. After pulmonary vein isolation, left atrial linear ablations were performed, and conduction gap sites were identified and ablated after first-touch radiofrequency application. Conduction gap(s) after the first-touch roof and septal linear ablation were observed in 13 (32%) and 19 patients (53%), respectively. Roof and septal area voltages were higher in patients with conduction gap(s) than in those without (roof, 1.23 ± 0.77 vs 0.73 ± 0.42 mV, p = 0.010; septal, 0.96 ± 0.43 vs 0.54 ± 0.18 mV, p = 0.001). Trisected regional analyses revealed that the voltage was higher at the region with a conduction gap than at the region without. Complete conduction block across the roof and septal lines was not achieved in 3 (7%) and 6 patients (17%), respectively. Patients in whom a linear conduction block could not be achieved demonstrated higher ablation area voltage than those with a successful conduction block (roof, 1.91 ± 0.74 vs 0.81 ± 0.51 mV, p = 0.001; septal, 1.15 ± 0.56 vs 0.69 ± 0.31 mV, p = 0.006). In conclusion, a high regional bipolar voltage predicts failure to achieve conduction block after left atrial roof or septal linear ablation. In addition, the conduction gap was located at the preserved voltage area. Copyright © 2017 Elsevier Inc. All rights reserved.
Polzin, K. A.; Pearson, J. B.; Webster, K.; Godfoy, T. J.; Bossard, J. A.
2013-01-01
Results of performance testing of an annular linear induction pump that has been designed for integration into a fission surface power technology demonstration unit are presented. The pump electromagnetically pushes liquid metal (NaK) through a specially-designed apparatus that permits quantification of pump performance over a range of operating conditions. Testing was conducted for frequencies of 40, 55, and 70 Hz, liquid metal temperatures of 125, 325, and 525 C, and input voltages from 30 to 120 V. Pump performance spanned a range of flow rates from roughly 0.3 to 3.1 L/s (4.8 to 49 gpm), and pressure heads of <1 to 104 kPa (<0.15 to 15 psi). The maximum efficiency measured during testing was 5.4%. At the technology demonstration unit operating temperature of 525 C the pump operated over a narrower envelope, with flow rates from 0.3 to 2.75 L/s (4.8 to 43.6 gpm), developed pressure heads from <1 to 55 kPa (<0.15 to 8 psi), and a maximum efficiency of 3.5%. The pump was supplied with three-phase power at 40 and 55 Hz using a variable-frequency motor drive, while power at 55 and 70 Hz was supplied using a variable-frequency power supply. Measured performance of the pump at 55 Hz using either supply exhibited good quantitative agreement. For a given temperature, the peak in efficiency occurred at different flow rates as the frequency was changed, but the maximum value of efficiency was relative insensitive within 0.3% over the frequency range tested, including a scan from 45 to 78 Hz. The objectives of the FSP technology project are as follows:5 • Develop FSP concepts that meet expected surface power requirements at reasonable cost with added benefits over other options. • Establish a nonnuclear hardware-based technical foundation for FSP design concepts to reduce overall development risk. • Reduce the cost uncertainties for FSP and establish greater credibility for flight system cost estimates. • Generate the key nonnuclear products to allow Agency
Shavezipur, M; Nieva, P; Khajepour, A; Hashemi, S M
2010-01-01
This paper presents a design technique that can be used to linearize the capacitance–voltage (C–V) response and extend the tuning range of parallel-plate-based MEMS tunable capacitors beyond that of conventional designs. The proposed technique exploits the curvature of the capacitor's moving electrode which could be induced by either manipulating the stress gradients in the plate's material or using bi-layer structures. The change in curvature generates a nonlinear structural stiffness as the moving electrode undergoes out-of-plane deformation due to the actuation voltage. If the moving plate curvature is tailored such that the capacitance increment is proportional to the voltage increment, then a linear C–V response is obtained. The larger structural resistive force at higher bias voltage also delays the pull-in and increases the maximum tunability of the capacitor. Moreover, for capacitors containing an insulation layer between the two electrodes, the proposed technique completely eliminates the pull-in effect. The experimental data obtained from different capacitors fabricated using PolyMUMPs demonstrate the advantages of this design approach where highly linear C–V responses and tunabilities as high as 1050% were recorded. The design methodology introduced in this paper could be easily extended to for example, capacitive pressure and temperature sensors or infrared detectors to enhance their response characteristics.
Mozer, AJ; Sariciftci, NS; Osterbacka, R; Westerling, M; Juska, G; LUTSEN, Laurence; VANDERZANDE, Dirk
2005-01-01
Charge carrier mobility and recombination in a bulk heterojunction solar cell based on the mixture of poly[2-methoxy-5-(3,7-dimethyloctyloxy)-phenylene vinylene] (MDMO-PPV) and 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)-C-61 (PCBM) has been studied using the novel technique of photoinduced charge carrier extraction in a linearly increasing voltage (Photo-CELIV). In this technique, charge carriers are photogenerated by a short laser flash, and extracted under a reverse bias voltage ramp after ...
Wang, Gang; Zhang, Zhonghua; Li, Zhengkun; Xu, Jinxin; You, Qiang
2016-01-01
Measurement of the mutual inductance is one of the key techniques in the joule balance to determine the Planck constant h, where a standard-square-wave compensation method was proposed to accurately measure the dc value of the mutual inductance. With this method, analog switches are used to compose an analog-switch signal generator to synthesize the excitation and compensation voltages. However, the accuracy of the compensation voltage is influenced by the non-ideal behaviors of analog-switches. In this paper, the effect from these non-ideal switches is analyzed in detail and evaluated with the equivalent circuits. A programmable Josephson voltage standard (PJVS) is used to generate a reference compensation voltage to measure the time integration of the voltage waveform generated by the analog-switch signal generator. Moreover, the effect is also evaluated experimentally by comparing the difference between the mutual inductance measured with the analog-switch signal generator and the value determined by the PJVS-analog-switch generator alternately in the same mutual inductance measurement system. The result shows that the impact of analog switches is 1.97 × 10 −7 with an uncertainty of 1.83 × 10 −7 (k = 1) and confirms that the analog switch method can be used regularly instead of the PJVS in the mutual inductance measurement for the joule balance experiment. (paper)
Improvement on the accuracy of beam bugs in linear induction accelerator
Xie Yutong; Dai Zhiyong; Han Qing
2002-01-01
In linear induction accelerator the resistive wall monitors known as 'beam bugs' have been used as essential diagnostics of beam current and location. The author presents a new method that can improve the accuracy of these beam bugs used for beam position measurements. With a fine beam simulation set, this method locates the beam position with an accuracy of 0.02 mm and thus can scale the beam bugs very well. Experiment results prove that the precision of beam position measurements can reach submillimeter degree
Design and performance of a 3.3-MeV linear induction accelerator (LIA)
Cheng Nianan; Zhang Shouyun; Tao Zucong
1992-01-01
A 3.3-MeV linear induction accelerator (LIA) has been designed and constructed at the China Academy of Engineering Physics. The parameters of 3.4 MeV, 2 kA, 80 ns and 1 x 10 4 A/(rad.cm) 2 have been achieved. It has been used for SG-1 FEL experiments. The accelerator is mounted on a movable frame so that , after moving 3 m transversely, it can be assembled with more modules into a 10-MeV LIA. The authors summarize the physics and engineering aspects of the LIA facility and describe the measuring means of characters for the beam
Application of an imperialist competitive algorithm to the design of a linear induction motor
Lucas, Caro; Nasiri-Gheidari, Zahra; Tootoonchian, Farid
2010-01-01
In this paper a novel optimization algorithm based on imperialist competitive algorithm (ICA) is used for the design of a low speed single sided linear induction motor (LIM). This type of motors is used increasingly in industrial process specially in transportation systems. In these applications having high efficiency with high power factor is very important. So in this paper the objective function of design is presented considering both efficiency and power factor. Finally the results of ICA are compared with the ones of genetic algorithm and conventional design. Comparison shows the success of ICA for design of LIMs.
Test results for three prototype models of a linear induction launcher
Zabar, Z.; Lu, X.N.; He, J.L.; Birenbaum, L.; Levi, E.; Kuznetsov, S.B.; Nahemow, M.D.
1991-01-01
This paper reports on the work on the linear induction launcher (LIL) started with an analytical study tht was followed by computer simulations and then was tested by laboratory models. Two mathematical representations have been developed to describe the launcher. The first, based on the field approach with sinusoidal excitation, has been validated by static tests on a small scale prototype fed at constant current and variable frequency. The second, a transient representation using computer simulation allows consideration of energization by means of a capacitor bank and a power conditioner. Tests performed on three small-scale prototypes up to 100 m/s muzzle velocities show good agreement with predicted performance
Zinchenko, V F; Tulisov, E V; Chlenov, A M; Shiyan, V D [Research Institute of Scientific Instruments, Turaevo-Lytkarino (Russian Federation)
1997-12-31
The results of experimental and theoretical optimization of the linear induction accelerator (LIA) design are presented. The major aim of the investigations was to maximize the bremsstrahlung output near the target face. The work was carried out in two stages: l) modernization of the injector module and 2) focusing of the relativistic electron beam (REB) produced at the exit of the accelerating system (AS) in the increasing axial magnetic field. In addition, the methods of diagnostics of angular and energetic parameters of REB based on measurements of radiation dose fields behind the target are described. (author). 2 figs., 4 refs.
High-efficiency FEL with Bragg resonator driven by linear induction accelerator
Ginzburg, N S; Kaminskij, A A; Kaminskij, A K; Peskov, N Yu; Sedykh, S N; Sergeev, A P; Sergeev, A S [Russian Academy of Sciences, Nizhny Novgorod (Russian Federation). Inst. of Applied Physics
1997-12-31
A narrow-band high-efficiency FEL-oscillator with a Bragg resonator was constructed based on a linear induction accelerator which formed a 1 MeV, 200 A, 200 ns electron beam. At the frequency of 31 GHz, radiation with a power of 31 MW and efficiency of 25% was measured. A high efficiency and a narrow width of the spectrum were achieved owing to the selective properties of the Bragg resonator in combination with the high quality of the helical electron beam formed in the reversed guide field regime. (author). 3 figs., 3 refs.
Bossamykin, V S; Gerasimov, A I; Gordeev, V S; Grishin, A V; Gritsina, V P; Tarasov, A D; Fedotkin, A S; Lazarev, S A; Averchenkov, A Ya [All-Russian Scientific Research Institute of Experimental Physics, Sarov (Russian Federation)
1997-12-31
The operating mode was studied of the LIA-30 linear induction accelerator ({approx} 40 MeV, {approx} 100 kA, {approx} 30 ns) with the generation of two bremsstrahlung pulses separated by a specified time interval from 0 to 5 {mu}s. In the accelerating channel an additional tube cathode was installed, and a synchronization system for two accelerating module groups triggering the formation and acceleration, at different initial times, of two annular electron beams with different outer diameters was changed. The energy limit of each beam electron acceleration can be controlled, and the energy sum limit is {<=} 540 MeV. (author). 2 tabs., 2 figs.
Particle Swarm Based Approach of a Real-Time Discrete Neural Identifier for Linear Induction Motors
Alma Y. Alanis
2013-01-01
Full Text Available This paper focusses on a discrete-time neural identifier applied to a linear induction motor (LIM model, whose model is assumed to be unknown. This neural identifier is robust in presence of external and internal uncertainties. The proposed scheme is based on a discrete-time recurrent high-order neural network (RHONN trained with a novel algorithm based on extended Kalman filter (EKF and particle swarm optimization (PSO, using an online series-parallel con figuration. Real-time results are included in order to illustrate the applicability of the proposed scheme.
Development of the methodology for the MHD analysis in a linear induction electro-magnetic pump
Seong, Seung Hwan; Hur, Seop; Kim, Seong O; Choi, Seok Ki; Wi, Myung Hwan; Jeon, Won Dae
2004-01-01
Generally, fast breeder reactors have adopted a liquid metal as a coolant for the heat transfer from the reactor to the heat exchangers. Since a liquid metal has an electrical conductivity, the pumping of the liquid metal may use an induction electro-magnetic (EM) pump which induces electrical current and body force on the metal flow. These linear induction pumps use a traveling magnetic field wave created by poly-phase currents and the induced currents and their associated magnetic field generate the Lorentz force whose effect can be actually the pumping of the liquid metal. The flow behaviors in the pump are very complex such as the existence of a rotational force, pulsation and so on, because the induction EM pump has time-varying magnetic fields and the induced convective currents which originate form the flow of the liquid metal. These phenomena generate a stability problem in the pump and depend on the changes of the magnetic field and fluid flow field due to the induced currents and the fluid flow of the liquid metal with time and complex pump geometry. Therefore, an exact flow analysis is required for designing and evaluating the stability of a pump
End effect braking force reduction in high-speed single-sided linear induction machine
Shiri, Abbas; Shoulaie, Abbas
2012-01-01
Highlights: ► A new analytical equation to model the end effect braking force of SLIM is derived. ► Equations for efficiency, power factor and output thrust are analytically derived. ► The effect of design variables on the performance of the motor is analyzed. ► An optimization method is employed to minimize the end effect braking force (EEBF). ► The results show that EEBF is minimized by appropriate selection of motor parameters. - Abstract: Linear induction motors have been widely employed in industry because of their simple structure and low construction cost. However, they suffer from low efficiency and power factor. In addition, existence of so called end effect influences their performance especially in high speeds. The end effect deteriorates the performance of the motor by producing braking force. So, in this paper, by using Duncan equivalent circuit model, a new analytical equation is proposed to model end effect braking force. Employing the proposed equation and considering all phenomena involved in the single-sided linear induction motor, a simple design procedure is presented and the effect of different design variables on the performance of the motor is analyzed. A multi-objective optimization method based on genetic algorithm is introduced to maximize efficiency and power factor, as well as to minimize the end effect braking force, simultaneously. Finally, to validate the optimization results, 2D finite element method is employed.
End Effects on the Linear Induction MHD Generator Calculated by Two-Sided Laplace Transform
Engeln, F.; Peschka, W. [Deutsche Versuchsanstalt fuer Luft- und Raumfahrt e.V., Institut fuer Energiewandlung und Elektrische Antriebe, Stuttgart, Federal Republic of Germany (Germany)
1966-11-15
In induction MHD systems special problems occur where the flow enters or leaves the magnetic field. These problems are generally described as end effects. Large gradients of the magnetic field are present at the inlet and also at the outlet of an MHD induction engine, these generating electric current systems in the fluid which may spoil the performance characteristics of the generator due to the interaction with the primary field of the engine. The two-dimensional induction MHD generator of finite length, using a polyphase winding system to obtain a travelling magnetic field, is treated as a boundary value problem by two-sided Laplace transform. For simplicity incompressibility is assumed. The two- dimensional boundary value problem of the induction engine is solved for - {infinity} Less-Than-Over-Equal-To x Less-Than-Over-Equal-To {infinity}. x is parallel to the flow direction of the linear MHD generator. In the region 0 Less-Than-Over-Equal-To x Less-Than-Over-Equal-To L the magnetic travelling wave is sinusoidal with a cyclical frequency {omega} and a phase-velocity v{sub s}. At x = 0 the conducting incompressible working fluid enters the field region and leaves it at the point-x = L. Two mathematical methods can be used to solve the boundary value problem, the Fourier transform or the two-sided Laplace transform. The latter offers the advantage of representing a complex analytical function in the image space. Moreover, it is possible to obtain the characteristics of the generator in the image space (e. g. field configuration, power flow function, etc.). That implies a large simplification of mathematical treatment. The solution in the original space then is given by asymptotic expansion of the known image function. (author)
Shi, Xiaoyu; Wu, Zhong-Shuai; Qin, Jieqiong; Zheng, Shuanghao; Wang, Sen; Zhou, Feng; Sun, Chenglin; Bao, Xinhe
2017-11-01
Printable supercapacitors are regarded as a promising class of microscale power source, but are facing challenges derived from conventional sandwich-like geometry. Herein, the printable fabrication of new-type planar graphene-based linear tandem micro-supercapacitors (LTMSs) on diverse substrates with symmetric and asymmetric configuration, high-voltage output, tailored capacitance, and outstanding flexibility is demonstrated. The resulting graphene-based LTMSs consisting of 10 micro-supercapacitors (MSs) present efficient high-voltage output of 8.0 V, suggestive of superior uniformity of the entire integrated device. Meanwhile, LTMSs possess remarkable flexibility without obvious capacitance degradation under different bending states. Moreover, areal capacitance of LTMSs can be sufficiently modulated by incorporating polyaniline-based pseudocapacitive nanosheets into graphene electrodes, showing enhanced capacitance of 7.6 mF cm -2 . To further improve the voltage output and energy density, asymmetric LTMSs are fabricated through controlled printing of linear-patterned graphene as negative electrodes and MnO 2 nanosheets as positive electrodes. Notably, the asymmetric LTMSs from three serially connected MSs are easily extended to 5.4 V, triple voltage output of the single cell (1.8 V), suggestive of the versatile applicability of this technique. Therefore, this work offers numerous opportunities of graphene and analogous nanosheets for one-step scalable fabrication of flexible tandem energy storage devices integrating with printed electronics on same substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Choi, Hojong; Woo, Park Chul; Yeom, Jung-Yeol; Yoon, Changhan
2017-04-04
A power MOSFET linearizer is proposed for a high-voltage power amplifier (HVPA) used in high-frequency pulse-echo instrumentation. The power MOSFET linearizer is composed of a DC bias-controlled series power MOSFET shunt with parallel inductors and capacitors. The proposed scheme is designed to improve the gain deviation characteristics of the HVPA at higher input powers. By controlling the MOSFET bias voltage in the linearizer, the gain reduction into the HVPA was compensated, thereby reducing the echo harmonic distortion components generated by the ultrasonic transducers. In order to verify the performance improvement of the HVPA implementing the power MOSFET linearizer, we measured and found that the gain deviation of the power MOSFET linearizer integrated with HVPA under 10 V DC bias voltage was reduced (-1.8 and -0.96 dB, respectively) compared to that of the HVPA without the power MOSFET linearizer (-2.95 and -3.0 dB, respectively) when 70 and 80 MHz, three-cycle, and 26 dB m input pulse waveforms are applied, respectively. The input 1-dB compression point (an index of linearity) of the HVPA with power MOSFET linearizer (24.17 and 26.19 dB m at 70 and 80 MHz, respectively) at 10 V DC bias voltage was increased compared to that of HVPA without the power MOSFET linearizer (22.03 and 22.13 dB m at 70 and 80 MHz, respectively). To further verify the reduction of the echo harmonic distortion components generated by the ultrasonic transducers, the pulse-echo responses in the pulse-echo instrumentation were compared when using HVPA with and without the power MOSFET linearizer. When three-cycle 26 dB m input power was applied, the second, third, fourth, and fifth harmonic distortion components of a 75 MHz transducer driven by the HVPA with power MOSFET linearizer (-48.34, -44.21, -48.34, and -46.56 dB, respectively) were lower than that of the HVPA without the power MOSFET linearizer (-45.61, -41.57, -45.01, and -45.51 dB, respectively). When five-cycle 20 dB m input
Pausas, Guifre Vendrell; Llimos Muntal, Pere; Jørgensen, Ivan Harald Holger
2017-01-01
This paper presents a high-voltage integrated regulator capable of sinking current for driving pulse-triggered level shifters in drivers for ultrasound applications. The regulator utilizes a new topology with a feedback loop and a current sinking circuit to satisfy the requirements of the portable....... The proposed design has been implemented in high-voltage 0.18 μm process whithin an area of 0.11 mm2 and it is suitable for system-on-chip integration due to its low component count and the fully integrated design....
Dynamic diagnostics of moving ferromagnetic material with the linear induction motor
Szewczyk Krzysztof
2017-01-01
Full Text Available The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were performed in the ANSYS MAXWELL environment. The results suggest the possibility of using this type of construction to test the quality of produced materials. The computational results and their analysis are presented in this article.
Zhao, J.; Zheng, T.Q.; Zhang, W.; Fang, J.; Liu, Y.M.
2011-01-01
A new type high temperature superconductor linear induction motor is designed and analyzed as a prototype to ensure applicability aimed at industrial motors. Made of Bi-2223/Ag, primary windings are distributed with the double-layer concentrated structure. The motor is analyzed by 2D electromagnetic Finite Element Method to get magnetic field distribution, thrust force, vertical force and so on. The critical current of motor and the electromagnetic force are mostly decided by the leakage flux density of primary slot and by the main magnetic flux and eddy current respectively. The structural parameters of motor have a great influence on the distribution of magnetic field. Under constant currents, the properties of motor are analyzed with different slot widths, slot heights and winding turns. The properties of motor, such as the maximum slot leakage flux density, motor thrust and motor vertical force, are analyzed with different structural parameters.
Kilbane, J.; Polzin, K. A.
2014-01-01
An annular linear induction pump (ALIP) that could be used for circulating liquid-metal coolant in a fission surface power reactor system is modeled in the present work using the computational COMSOL Multiphysics package. The pump is modeled using a two-dimensional, axisymmetric geometry and solved under conditions similar to those used during experimental pump testing. Real, nonlinear, temperature-dependent material properties can be incorporated into the model for both the electrically-conducting working fluid in the pump (NaK-78) and structural components of the pump. The intricate three-phase coil configuration of the pump is implemented in the model to produce an axially-traveling magnetic wave that is qualitatively similar to the measured magnetic wave. The model qualitatively captures the expected feature of a peak in efficiency as a function of flow rate.
Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems
Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long
2017-01-01
According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable. (paper)
Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems
Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long
2017-07-01
According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable.
Rail Brake System Using a Linear Induction Motor for Dynamic Braking
Sakamoto, Yasuaki; Kashiwagi, Takayuki; Tanaka, Minoru; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo
One type of braking system for railway vehicles is the eddy current brake. Because this type of brake has the problem of rail heating, it has not been used for practical applications in Japan. Therefore, we proposed the use of a linear induction motor (LIM) for dynamic braking in eddy current brake systems. The LIM reduces rail heating and uses an inverter for self excitation. In this paper, we estimated the performance of an LIM from experimental results of a fundamental test machine and confirmed that the LIM generates an approximately constant braking force under constant current excitation. At relatively low frequencies, this braking force remains unaffected by frequency changes. The reduction ratio of rail heating is also approximately proportional to the frequency. We also confirmed that dynamic braking resulting in no electrical output can be used for drive control of the LIM. These characteristics are convenient for the realization of the LIM rail brake system.
Analysis and measure of novel stereo-garage driven by linear induction motor
Lu Qinfen
2015-12-01
Full Text Available The car access time is a key parameter, especially in a huge stereo-garage, where this one should be decreased as much as possible. This paper proposes a novel stereo-garage. Adopting the linear induction motors (LIMs, the system has a simple structure and rapid response capability. In the stereo-garage, several LIMs are installed below the crossbeam on a lifting platform, and several LIMs are fixed on the top of a moving frame. During the operation of LIMs, the moving frame moves forward and backward to reach the required parking place, whereas the crossbeam moves horizontally in order to take or store the vehicle rapidly. All these LIMs are the same and should be designed at a low frequency. The influences of key structure parameters and dynamic performances are investigated, based on FEM. The predicted results are validated by a prototype. Finally, the designed LIMs are successfully applied in two 8-layer stereo-garages.
Effect of accelerating gap geometry on the beam breakup instability in linear induction accelerators
Miller, R.B.; Marder, B.M.; Coleman, P.D.; Clark, R.E.
1988-01-01
The electron beam in a linear induction accelerator is generally susceptible to growth of the transverse beam breakup instability. In this paper we analyze a new technique for reducing the transverse coupling between the beam and the accelerating cavities, thereby reducing beam breakup growth. The basic idea is that the most worrisome cavity modes can be cutoff by a short section of coaxial transmission line inserted between the cavity structure and the accelerating gap region. We have used the three-dimensional simulation code SOS to analyze this problem. In brief, we find that the technique works, provided that the lowest TE mode cutoff frequency in the coaxial line is greater than the frequency of the most worrisome TM mode of the accelerating cavity
Modeling of fully coupled MHD flows in annular linear induction pumps
Roman, C.; Dumont, M.; Letout, S.; Courtessole, C.; Fautrelle, Y.; Vitry, S.; Rey, F.
2014-01-01
The paper studies specific pumping characteristics of the Annular Linear Induction Pumps (ALIP) with travelling field for liquid sodium. The present work is focused on the analysis of very large electromagnetic pumps able to provide high flow rates. The magnetic Reynolds number is quite large, therefore, it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside pump channel. We couple the electromagnetic aspects with the hydrodynamic ones by means of two commercial softwares. The geometry considered here is 2D axisymmetric. It is found that in such induction pumps the effect of convection is very important. Two main effects have been put forth. Firstly, due to the magnetic entrainment significant end effects are observed for large velocities. This leads to the existence of regions where the axial force is negative. Secondly, a Hartmann effect occurs near the walls. The electric current and the corresponding forces are confined near the wall in Hartmann layers. Global stability of e.m. pump is also analysed. (authors)
Indigenous development of 20 Cu. M/hr flat linear induction pump (Paper No. 047)
Prabhakar, R; Prakash, V; Sundarasekaran, S
1987-01-01
A distinctive physical property of sodium metal which is used as a coolant in fast reactors, is its high electrical conductivity. This together with its ability to wet stainless steel permits fluid pumping techniques using electromagnetic devices. Electromagnetic pumps are analogous to the electric motor, in which a force is produced by the interaction of magnetic field and current flowing in a conductor. Flat linear induction pump (FLIP) whose operating principle is similar to that of an induction motor is one of the types of electromagnetic pumps in wide use in auxilary circuits of fast reactors. As part of efforts to develop fast reactor components indigenously, work on the design and construction of a prototype FLIP rated for 20Cu.M/hr and 5Kg/sq.cm at 550degC was initiated. Under Board of Research in Nuclear Sciences scheme, the design was carried out by the Electrical Engineering Department of IIT, Madras. Pump was constructed at Engineering Development Division, Indira Gandhi Centre for Atomic Research, Kalpakkam. This paper presents in detail the work carried out for the fabrication of flow channel and for the stator assembly. Results obtained from dry electrical tests are also reported. Appendix summarises the design data. (author).
Zhang Jun; Guo Yu-Feng; Xu Yue; Lin Hong; Yang Hui; Hong Yang; Yao Jia-Fei
2015-01-01
A novel one-dimensional (1D) analytical model is proposed for quantifying the breakdown voltage of a reduced surface field (RESURF) lateral power device fabricated on silicon on an insulator (SOI) substrate. We assume that the charges in the depletion region contribute to the lateral PN junctions along the diagonal of the area shared by the lateral and vertical depletion regions. Based on the assumption, the lateral PN junction behaves as a linearly graded junction, thus resulting in a reduced surface electric field and high breakdown voltage. Using the proposed model, the breakdown voltage as a function of device parameters is investigated and compared with the numerical simulation by the TCAD tools. The analytical results are shown to be in fair agreement with the numerical results. Finally, a new RESURF criterion is derived which offers a useful scheme to optimize the structure parameters. This simple 1D model provides a clear physical insight into the RESURF effect and a new explanation on the improvement in breakdown voltage in an SOI RESURF device. (paper)
Mozer, A. J.; Sariciftci, N. S.; Lutsen, L.; Vanderzande, D.; Österbacka, R.; Westerling, M.; Juška, G.
2005-03-01
Charge carrier mobility and recombination in a bulk heterojunction solar cell based on the mixture of poly[2-methoxy-5-(3,7-dimethyloctyloxy)-phenylene vinylene] (MDMO-PPV) and 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)-C61 (PCBM) has been studied using the novel technique of photoinduced charge carrier extraction in a linearly increasing voltage (Photo-CELIV). In this technique, charge carriers are photogenerated by a short laser flash, and extracted under a reverse bias voltage ramp after an adjustable delay time (tdel). The Photo-CELIV mobility at room temperature is found to be μ =2×10-4cm2V-1s-1, which is almost independent on charge carrier density, but slightly dependent on tdel. Furthermore, determination of charge carrier lifetime and demonstration of an electric field dependent mobility is presented.
Patel, Akhil, E-mail: akhilpatel@rrcat.gov.in; Kale, Umesh; Shrivastava, Purushottam
2017-04-21
The Line type modulators have been widely used to generate high voltage rectangular pulses to power the klystron for high power RF generation. In Line type modulator, the Pulse Forming Network (PFN) which is a cascade combination of lumped capacitors and inductors is used to store the electrical energy. The charged PFN is then discharged into a klystron by firing a high voltage Thyratron switch. This discharge generates a high voltage rectangular pulse across the klystron electrodes. The amplitude and phase of Klystron's RF output is governed by the high voltage pulse amplitude. The undesired RF amplitude and phase stability issues arises at the klystron's output due to inter-pulse and during the pulse amplitude variations. To reduce inter-pulse voltage variations, the PFN is required to be charged at the same voltage after every discharge cycle. At present, the combination of widely used resonant charging and deQing method is used to regulate the pulse to pulse PFN voltage variations but the charging transformer's leakage inductance puts an upper bound on the regulation achievable by this method. Here we have developed few insights of the deQing process and devised a new compensation method to compensate this undesired effect of charging transformer's leakage inductance on the pulse to pulse PFN voltage stability. This compensation is accomplished by the controlled partial discharging of the split PFN capacitor using a low voltage MOSFET switch. Theoretically, very high values of pulse to pulse voltage stability may be achieved using this method. This method may be used in deQing based existing modulators or in new modulators, to increase the pulse to pulse voltage stability, without having a very tight bound on charging transformer's leakage inductance. Given a stable charging power supply, this method may be used to further enhance the inter-pulse voltage stability of modulators which employ the direct charging, after replacing the
A 5 V-to-3.3 V CMOS Linear Regulator with Three-Output Temperature-Independent Reference Voltages
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.
Vidal, P.E.
2004-12-15
This study deals with linear and non-linear control strategies applied to the rotation speed feedback of a doubly fed induction machine (DFIM), whose stator and rotor windings are connected to two Pulse Width Modulation voltage source inverters. We choose to distribute the active powers between the stator and the rotor following a certain proportionality ratio. This leads to guarantee, in steady state operation, a stator and rotor angular frequencies sharing. This distribution is initially assured by two shared angular frequencies controllers, and in a second time by the means of the Park transformation angles directly. Two models are established: the first express the currents, and the second is linked with the fluxes. The simulations results of the linear control (field oriented control), and non-linear control (sliding mode control), show a good independence between the main flux and the torque. An experimental validation is also presented. The results presented show the satisfactory DFIM flux control. Special attention is paid to the active power dispatching. (author)
Wei Wang
2016-03-01
Full Text Available Overhead high voltage power line (HVPL online monitoring equipment is playing an increasingly important role in smart grids, but the power supply is an obstacle to such systems’ stable and safe operation, so in this work a hybrid wireless power supply system, integrated with inductive energy harvesting and wireless power transmitting, is proposed. The energy harvesting device extracts energy from the HVPL and transfers that from the power line to monitoring equipment on transmission towers by transmitting and receiving coils, which are in a magnetically coupled resonant configuration. In this paper, the optimization design of online energy harvesting devices is analyzed emphatically by taking both HVPL insulation distance and wireless power supply efficiency into account. It is found that essential parameters contributing to more extracted energy include large core inner radius, core radial thickness, core height and small core gap within the threshold constraints. In addition, there is an optimal secondary coil turn that can maximize extracted energy when other parameters remain fixed. A simple and flexible control strategy is then introduced to limit power fluctuations caused by current variations. The optimization methods are finally verified experimentally.
G.M. Golenkov
2014-03-01
Full Text Available The paper presents results of computer simulation and experimental study of magnetic induction distribution in a coaxial linear motor air gap throughout the length of the runner active part at different heights of the air gap between the runner and the inductor magnetic core for motors with axial and radial direction of the permanent magnets magnetization.
A Capacitor-Free, Fast Transient Response Linear Voltage Regulator In a 180nm CMOS
Deleuran, Alexander N.; Lindbjerg, Nicklas; Pedersen, Martin K.
2015-01-01
A 1.8 V capacitor-free linear regulator with fast transient response based on a new topology with a fast and slow regulation loop is presented. The design has been laid out and simulated in a 0.18 µm CMOS process. The design has a low component count and is tailored for system-on-chip integration...
Direct measurement of the image displacement instability in a linear induction accelerator
Burris-Mog, T. J.; Ekdahl, C. A.; Moir, D. C.
2017-06-01
The image displacement instability (IDI) has been measured on the 20 MeV Axis I of the dual axis radiographic hydrodynamic test facility and compared to theory. A 0.23 kA electron beam was accelerated across 64 gaps in a low solenoid focusing field, and the position of the beam centroid was measured to 34.3 meters downstream from the cathode. One beam dynamics code was used to model the IDI from first principles, while another code characterized the effects of the resistive wall instability and the beam break-up (BBU) instability. Although the BBU instability was not found to influence the IDI, it appears that the IDI influences the BBU. Because the BBU theory does not fully account for the dependence on beam position for coupling to cavity transverse magnetic modes, the effect of the IDI is missing from the BBU theory. This becomes of particular concern to users of linear induction accelerators operating in or near low magnetic guide fields tunes.
Direct measurement of the image displacement instability in a linear induction accelerator
T. J. Burris-Mog
2017-06-01
Full Text Available The image displacement instability (IDI has been measured on the 20 MeV Axis I of the dual axis radiographic hydrodynamic test facility and compared to theory. A 0.23 kA electron beam was accelerated across 64 gaps in a low solenoid focusing field, and the position of the beam centroid was measured to 34.3 meters downstream from the cathode. One beam dynamics code was used to model the IDI from first principles, while another code characterized the effects of the resistive wall instability and the beam break-up (BBU instability. Although the BBU instability was not found to influence the IDI, it appears that the IDI influences the BBU. Because the BBU theory does not fully account for the dependence on beam position for coupling to cavity transverse magnetic modes, the effect of the IDI is missing from the BBU theory. This becomes of particular concern to users of linear induction accelerators operating in or near low magnetic guide fields tunes.
Suppressing beam-centroid motion in a long-pulse linear induction accelerator
Carl Ekdahl
2011-12-01
Full Text Available The second axis of the dual-axis radiography of hydrodynamic testing (DARHT facility produces up to four radiographs within an interval of 1.6 μs. It does this by slicing four micropulses out of a 2-μs long electron beam pulse and focusing them onto a bremsstrahlung converter target. The 1.8-kA beam pulse is created by a dispenser cathode diode and accelerated to more than 16 MeV by the unique DARHT Axis-II linear induction accelerator (LIA. Beam motion in the accelerator would be a problem for multipulse flash radiography. High-frequency motion, such as from beam-breakup (BBU instability, would blur the individual spots. Low-frequency motion, such as produced by pulsed-power variation, would produce spot-to-spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it. Using the methods discussed, we have reduced beam motion at the accelerator exit to less than 2% of the beam envelope radius for the high-frequency BBU, and less than 1/3 of the envelope radius for the low-frequency sweep.
Linear induction accelerators at the Los Alamos National Laboratory DARHT facility
Nath, Subrata
2010-01-01
The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory consists of two linear induction accelerators at right angles to each other. The First Axis, operating since 1999, produces a nominal 20-MeV, 2-kA single beam-pulse with 60-nsec width. In contrast, the DARHT Second Axis, operating since 2008, produces up to four pulses in a variable pulse format by slicing micro-pulses out of a longer ∼1.6-microseconds (flat-top) pulse of nominal beam-energy and -current of 17 MeV and 2 kA respectively. Bremsstrahlung x-rays, shining on a hydro-dynamical experimental device, are produced by focusing the electron beam-pulses onto a high-Z target. Variable pulse-formats allow for adjustment of the pulse-to-pulse doses to record a time sequence of x-ray images of the explosively driven imploding mock device. Herein, we present a sampling of the numerous physics and engineering aspects along with the current status of the fully operational dual axes capability. First successful simultaneous use of both the axes for a hydrodynamic experiment was achieved in 2009.
Design of a MeV, 4kA linear induction accelerator for flash radiography
Kulke, B.; Brier, R.; Chapin, W.
1981-01-01
For verifying the hydrodynamics of nuclear weapons design it is useful to have flash x-ray machines that can deliver a maximum dose in a minimum pulse length and with very high reliability. At LLNL, such a requirement was identified some years ago as 500 roentgens at one meter, in a 60 nsec pulse length. In response to this requirement, a linear induction accelerator was proposed to and funded by DOE in 1977. The design of this machine, called FXR, has now been completed and construction has begun. The FXR design extends the parameters of a similar machine that had been built and operated at LBL, Berkeley, some ten years ago. Using a cold cathode injector followed by 48 accelerator modules rated at 400 kV each, the FXR machine will accelerate a 4 kA electron beam pulse to 20 MeV final energy. Key design features are the generation and the stable transport of a low emittance (100 mr-cm) beam from a field emitter diode, the design of reliable, compact energy storage components such as Blumleins, feedlines and accelerator modules, and a computer-assisted control system
The Experimental Study of Rayleigh-Taylor Instability using a Linear Induction Motor Accelerator
Yamashita, Nicholas; Jacobs, Jeffrey
2009-11-01
The experiments to be presented utilize an incompressible system of two stratified miscible liquids of different densities that are accelerated in order to produce the Rayleigh-Taylor instability. Three liquid combinations are used: isopropyl alcohol with water, a calcium nitrate solution or a lithium polytungstate solution, giving Atwood numbers of 0.11, 0.22 and 0.57, respectively. The acceleration required to drive the instability is produced by two high-speed linear induction motors mounted to an 8 m tall drop tower. The motors are mounted in parallel and have an effective acceleration length of 1.7 m and are each capable of producing 15 kN of thrust. The liquid system is contained within a square acrylic tank with inside dimensions 76 x76x184 mm. The tank is mounted to an aluminum plate, which is driven by the motors to create constant accelerations in the range of 1-20 g's, though the potential exists for higher accelerations. Also attached to the plate are a high-speed camera and an LED backlight to provide continuous video of the instability. In addition, an accelerometer is used to provide acceleration measurements during each experiment. Experimental image sequences will be presented which show the development of a random three-dimensional instability from an unforced initial perturbation. Measurements of the mixing zone width will be compared with traditional growth models.
Andrzej Rusek
2008-01-01
Full Text Available The mathematical model of cylindrical linear induction motor (C-LIM fed via frequency converter is presented in the paper. The model was developed in order to analyze numerically the transient states. Problems concerning dynamics of ac-machines especially linear induction motor are presented in [1 – 7]. Development of C-LIM mathematical model is based on circuit method and analogy to rotary induction motor. The analogy between both: (a stator and rotor windings of rotary induction motor and (b winding of primary part of C-LIM (inductor and closed current circuits in external secondary part of C-LIM (race is taken into consideration. The equations of C-LIM mathematical model are presented as matrix together with equations expressing each vector separately. A computational analysis of selected transient states of C-LIM fed via frequency converter is presented in the paper. Two typical examples of C-LIM operation are considered for the analysis: (a starting the motor at various static loads and various synchronous velocities and (b reverse of the motor at the same operation conditions. Results of simulation are presented as transient responses including transient electromagnetic force, transient linear velocity and transient phase current.
王铁成; 李伟力; 孙建伟
2003-01-01
A mathematical model has been built up for compound cage rotor induction machine with the rotor re-sistance and leakage inductance in the model identified through Kalman filtering method. Using the identifiedparameters, simulation studies are performed, and simulation results are compared with testing results.
Piyarat, Wekin; Kinnares, Vijit
This paper presents a performance evaluation and a simple speed control method of an asymmetrical parameter type two-phase induction motor drive using a three-leg VSI (Voltage Source Inverter). The two-phase induction motor is adapted from an existing single-phase induction motor resulting in impedance unbalance between main and auxiliary windings. The unbalanced two-phase inverter outputs with orthogonal displacement based on a SPWM (Sinusoidal Pulse Width Modulation) method are controlled with appropriate amplitudes for improving the motor performance. Dynamic simulation of the proposed drive system is given. A simple speed controller based on a slip regulation method is designed. The overall system is implemented on a DSP (Digital Signal Processor) board. The validity of the proposed system is verified by simulation and experimental results.
Nashine, B.K.; Rao, B.P.C.
2014-01-01
Highlights: • Derivation of applicable design equations. • Design of an annular induction pump based on these equations. • Testing of the designed pump in a sodium test facility. • Performance evaluation of the designed pump. - Abstract: Annular linear induction pumps (ALIPs) are used for pumping electrically conducting liquid metals. These pumps find wide application in fast reactors since the coolant in fast reactors is liquid sodium which a good conductor of electricity. The design of these pumps is usually done using equivalent circuit approach in combination with numerical simulation models. The equivalent circuit of ALIP is similar to that of an induction motor. This paper presents the derivation of equivalent circuit parameters using first principle approach. Sodium testing of designed ALIP using the equivalent circuit approach is also described and experimental results of the testing are presented. Comparison between experimental and analytical calculations has also been carried out. Some of the reasons for variation have also been listed in this paper
Fox, Christopher; Simon, Tom; Simon, Bill; Dempsey, James F.; Kahler, Darren; Palta, Jatinder R.; Liu Chihray; Yan Guanghua [Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 and Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); NRE, 202 Nuclear Science Building, University of Florida, P.O. Box 118300, Gainesville, Florida 32611-8300 and Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); Sun Nuclear Inc., 425-A Pineda Court, Melbourne, Florida 32940 (United States); ViewRay Inc., 2 Thermo Fisher Way, Oakwood Village, Ohio 44146 (United States); Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)
2010-02-15
Purpose: Accurate modeling of beam profiles is important for precise treatment planning dosimetry. Calculated beam profiles need to precisely replicate profiles measured during machine commissioning. Finite detector size introduces perturbations into the measured profiles, which, in turn, impact the resulting modeled profiles. The authors investigate a method for extracting the unperturbed beam profiles from those measured during linear accelerator commissioning. Methods: In-plane and cross-plane data were collected for an Elekta Synergy linac at 6 MV using ionization chambers of volume 0.01, 0.04, 0.13, and 0.65 cm{sup 3} and a diode of surface area 0.64 mm{sup 2}. The detectors were orientated with the stem perpendicular to the beam and pointing away from the gantry. Profiles were measured for a 10x10 cm{sup 2} field at depths ranging from 0.8 to 25.0 cm and SSDs from 90 to 110 cm. Shaping parameters of a Gaussian response function were obtained relative to the Edge detector. The Gaussian function was deconvolved from the measured ionization chamber data. The Edge detector profile was taken as an approximation to the true profile, to which deconvolved data were compared. Data were also collected with CC13 and Edge detectors for additional fields and energies on an Elekta Synergy, Varian Trilogy, and Siemens Oncor linear accelerator and response functions obtained. Response functions were compared as a function of depth, SSD, and detector scan direction. Variations in the shaping parameter were introduced and the effect on the resulting deconvolution profiles assessed. Results: Up to 10% setup dependence in the Gaussian shaping parameter occurred, for each detector for a particular plane. This translated to less than a {+-}0.7 mm variation in the 80%-20% penumbral width. For large volume ionization chambers such as the FC65 Farmer type, where the cavity length to diameter ratio is far from 1, the scan direction produced up to a 40% difference in the shaping
Fox, Christopher; Simon, Tom; Simon, Bill; Dempsey, James F.; Kahler, Darren; Palta, Jatinder R.; Liu Chihray; Yan Guanghua
2010-01-01
Purpose: Accurate modeling of beam profiles is important for precise treatment planning dosimetry. Calculated beam profiles need to precisely replicate profiles measured during machine commissioning. Finite detector size introduces perturbations into the measured profiles, which, in turn, impact the resulting modeled profiles. The authors investigate a method for extracting the unperturbed beam profiles from those measured during linear accelerator commissioning. Methods: In-plane and cross-plane data were collected for an Elekta Synergy linac at 6 MV using ionization chambers of volume 0.01, 0.04, 0.13, and 0.65 cm 3 and a diode of surface area 0.64 mm 2 . The detectors were orientated with the stem perpendicular to the beam and pointing away from the gantry. Profiles were measured for a 10x10 cm 2 field at depths ranging from 0.8 to 25.0 cm and SSDs from 90 to 110 cm. Shaping parameters of a Gaussian response function were obtained relative to the Edge detector. The Gaussian function was deconvolved from the measured ionization chamber data. The Edge detector profile was taken as an approximation to the true profile, to which deconvolved data were compared. Data were also collected with CC13 and Edge detectors for additional fields and energies on an Elekta Synergy, Varian Trilogy, and Siemens Oncor linear accelerator and response functions obtained. Response functions were compared as a function of depth, SSD, and detector scan direction. Variations in the shaping parameter were introduced and the effect on the resulting deconvolution profiles assessed. Results: Up to 10% setup dependence in the Gaussian shaping parameter occurred, for each detector for a particular plane. This translated to less than a ±0.7 mm variation in the 80%-20% penumbral width. For large volume ionization chambers such as the FC65 Farmer type, where the cavity length to diameter ratio is far from 1, the scan direction produced up to a 40% difference in the shaping parameter between in
Budisan, N. [Politechnica Univ. of Timisoara (Romania); Hentea, T.; Mahil, S. [Purdue Univ. Calumet, Hammond, IN (United States); Madescu, G. [Romanian Academy, Timisoara (Romania)
1996-12-31
In this paper we present the results of our investigations concerning the utilization of induction generators at very low speed. It is shown that, by proper design, it is possible to obtain high efficiency and high power factor values. The optimized induction generators require lower reactive power resulting in lower size and price of the excitation control system. 4 refs., 2 figs.
Development of heavy ion induction linear accelerators as drivers for inertial confinement fusion
Warwick, A.I.; Celata, C.; Faltens, A.; Fessenden, T.J.; Judd, D.L.; Keefe, D.; Kim, C.H.; Laslett, L.J.; Lee, E.P.; Meuth, H.
1988-01-01
This paper reports on a continuing study in the USA of the feasibility of an induction linac fusion driver, which would accelerate multiple heavy-ion beams through a sequence of pulsed transformers and amplify the beam current during acceleration. The driver cost could be $200/Joule or less and the cost of electricity in the range of .050-.055$/kWhr. As a next stage of development to assess the feasibility of this approach the authors propose an Induction Linac Systems Experiment. This will test some of the technology and multiple-beam manipulations necessary for a fusion driver
Development of heavy ion induction linear accelerators as drivers for inertial confinement fusion
Warwick, A.I.; Celata, C.; Faltens, A.
1988-06-01
There is a continuing study in the USA of the feasibility of an induction linac fusion driver, which would accelerate multiple heavy-ion beams through a sequence of pulsed transformers and amplify the beam current during acceleration. The driver cost could be $200/Joule or less and the cost of electricity in the range of .050-.055$/kWhr. As a next stage of development to assess the feasibility of this approach we propose an ''Induction Linac Systems Experiment''. This will test some of the technology and multiple-beam manipulations necessary for a fusion driver. 7 refs., 1 fig
Input-output linearizing tracking control of induction machine with the included magnetic saturation
Dolinar, Drago; Ljusev, Petar; Stumberger, Gorazd
2003-01-01
The tracking control design of an induction motor, based on input-output linearisation with magnetic saturation included is addressed. The magnetic saturation is represented by a nonlinear magnetising curve for the iron core and is used in the control, the observer of the state variables......, and in the load torque estimator. An input-output linearising control is used to achieve better tracking performances. It is based on the mixed 'stator current - rotor flux linkage' induction motor model with magnetic saturation considered in the stationary reference frame. Experimental results show...... that the proposed input-output linearising tracking control with saturation included behaves considerably better than the one without saturation, and that it introduces smaller position and speed errors, and better motor stiffness on account of the increased computational complexity....
Kirillov, I.R.; Obukhov, D.M.
2005-01-01
One introduces a completely two-dimensional mathematical model to calculate characteristics of induction magnetohydrodynamic (MHD) machines with a cylindrical channel. On the basis of the numerical analysis one obtained a pattern of liquid metal flow in a electromagnetic pump at presence of the MHD-instability characterized by initiation of large-scale vortices propagating longitudinally and azimuthally. Comparison of the basic calculated characteristics of pump with the experiment shows their adequate qualitative and satisfactory quantitative coincidence [ru
Yang, Yongheng; Sangwongwanich, Ariya; Liu, Hongpeng
2017-01-01
In this paper, a cost-effective control scheme for two-stage grid-connected PhotoVoltaic (PV) systems in Low Voltage Ride-Through (LVRT) operation is proposed. In the case of LVRT, the active power injection by PV panels should be limited to prevent from inverter over-current and also energy...... aggregation at the dc-link, which will challenge the dc-link capacitor lifetime if remains uncontrolled. At the same time, reactive currents should be injected upon any demand imposed by the system operators. In the proposed scheme, the two objectives can be feasibly achieved. The active power is regulated...... point tracking controller without significant hardware or software modifications. In this way, the PV system will not operate at the maximum power point, whereas the inverter will not face any over-current challenge but can provide reactive power support in response to the grid voltage fault...
Liu, C.-T.; Lin, S.-Y.; Yang, Y.-Y.
2005-01-01
A detailed mathematical approach for analyzing static/dynamic characteristics of a linear induction motor for steel mill non-contacting conveyance system application will be provided. The dependent reluctances among the motor secondary steel plate and primary poles have been systematically formulated; hence, the operational performance of the system can be derived conveniently. Results showed that not only the motor structure is suitable for the design objective, but also the proposed magnetic equivalent circuit can provide appropriate and convenient modeling for relative analytical investigations
Shen, Yang-Wu; Ke, De-Ping; Sun, Yuan-Zhang; Daniel, Kirschen; Wang, Yi-Shen; Hu, Yuan-Chao
2015-07-01
A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator (DFIG) equipped with a superconducting magnetic energy storage (SMES) device to enhance its transient voltage and frequency support capacity during grid faults. The SMES connected to the DC-link capacitor of the DFIG is controlled to regulate the transient dc-link voltage so that the whole capacity of the grid side converter (GSC) is dedicated to injecting reactive power to the grid for the transient voltage support. However, the rotor-side converter (RSC) has different control tasks for different periods of the grid fault. Firstly, for Period I, the RSC injects the demagnetizing current to ensure the controllability of the rotor voltage. Then, since the dc stator flux degenerates rapidly in Period II, the required demagnetizing current is low in Period II and the RSC uses the spare capacity to additionally generate the reactive (priority) and active current so that the transient voltage capability is corroborated and the DFIG also positively responds to the system frequency dynamic at the earliest time. Finally, a small amount of demagnetizing current is provided after the fault clearance. Most of the RSC capacity is used to inject the active current to further support the frequency recovery of the system. Simulations are carried out on a simple power system with a wind farm. Comparisons with other commonly used control methods are performed to validate the proposed control method. Project supported by the National Natural Science Foundation of China (Grant No. 51307124) and the Major Program of the National Natural Science Foundation of China (Grant No. 51190105).
Confinement of a high current proton beam in a linear induction accelerator
Kerslick, G.S.; Roth, I.S.; Golkowski, C.; Ivers, J.D.; Nation, J.A.
1987-01-01
A 1 MeV, 6 kA, 50 ns annular proton beam has been generated in a two stage induction linac. Several confinement systems designed to allow propagation through multiple acceleration stages have been studied. In the first, the beam is injected through a half cusp into a 1.4 T solenoidal magnetic field. In the second system the beam is generated in a full cusp diode. The third system discussed relies on collective confinement of the protons by the space charge of the neutralizing electrons. This is in contrast to the previously described systems which rely on magnetic confinement. A comparison between the three methods of transport is made
Ardhia Wishnuprakasa
2016-12-01
Full Text Available In this study, the IEEE 519 Standard as a basis benchmarking for voltage (THDV and current (THDI in draft performance. Comparative Study based onthree-techniques of 2-Level Converter (2LC by using a Star-Connection Induction Motor (Y-CIM in ExtraLow Voltage (ELV Configuration.For the detail explanation, a primary inverter as Direct-Inverterby PWMdirect (PWM degreesand asecondary inverter as Inverse-Inverterby PWMinverse(PWM + PI degrees. It tends a modified algorithm,for eachof SPWM in six rules, and FHIPWM in 5th harmonics Injectedin standard modulation as the purpose for the Open-Ends of Pre-Dual Inverter in Decoupled SPWM for twelve rules, and Decoupled FHIPWM in combination of 5th harmonics Injectedin combination of two-standard-modulation. Those techniques are the purpose of two-inverter combination, which namelythe Equal Direct-Inverse (EDI algorithmproduct of prototyping in similarities. The observation is restricted in voltage scope between Simulation by using Power Simulator (PSIMand Application by using Microcontroller ARM STM32F4 Discovery.
Turner, W.C.; Barrett, D.M.; Sampayan, S.E.
1991-01-01
In this paper the authors attempt to motivate the development of modeling tools for linear induction accelerator components by giving examples of performance limitations related to energy sweep. The most pressing issues is the development of an accurate model of the switching behavior of large magnetic cores at high dB/dt in the accelerator and magnetic compression modulators. Ideally one would like to have a model with as few parameters as possible that allows the user to choose the core geometry and magnetic material and perhaps a few parameters characterizing the switch model. Beyond this, the critical modeling tasks are: simulation of a magnetic compression modulator, modeling the reset dynamics of a magnetic compression modulator, modeling the loading characteristics of a linear induction accelerator cell, and modeling the electron injector current including the dynamics of feedback modulation and beam loading in an accelerator cell. Of course in the development of these models care should be given to benchmarking them against data from experimental systems. Beyond that one should aim for tools that have predictive power so that they can be used as design tools and not merely to replicate existing data
Li, H.; Ye, R.; Han, L.
2010-01-01
In order to entirely analyze the transient performances of a grid-connected doubly fed induction generator (DFIG) wind turbine under the different operational states, based on the transient models of DFIG, a two-mass wind turbine electrical equivalent model considering the torsional flexibility o...
Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav
2015-01-01
Roč. 97, č. 2 (2015), s. 155-164 ISSN 0948-7921 R&D Projects: GA ČR GA13-35370S Institutional support: RVO:61388998 Keywords : six-phase induction machine * symmetrical components * spatial harmonics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.662, year: 2015
Speed Sensorless mixed sensitivity linear parameter variant H_inf control of the induction motor
Toth, R.; Fodor, D.
2004-01-01
The paper shows the design of a robust control structure for the speed sensorless vector control of the IM, based on the mixed sensitivity (MS) linear parameter variant (LPV) H8 control theory. The controller makes possible the direct control of the flux and speed of the motor with torque adaptation
Magnetic field alignment for a 20 MeV linear induction accelerator
Zhang Wenwei; Pan Haifeng; Li Hong; Liu Yunlong; Zhang Linwen
2002-01-01
'Dragon-1' accelerator now is being constructed in CAEP. It will produce high current pulse electron beams. The main components of the accelerator include 72 induction accelerating cells and 18 connection cells with ports for beam di gnostic hardware and vacuum pump. In order to acquire high quality beams, a lot of problems have to be addressed such as to reduce the emittance, to control the increase of corkscrew and so on. The alignment of the focus magnetic field is the most concerned. A laser track has been used for mechanical alignment, magnetic alignment is performed by using pulsed-wire technique, and the natural tilt errors is corrected by a pair of steering coil, which is located inside the cell
Performance of MBE-4: An experimental multiple beam induction linear accelerator for heavy ions
Warwick, A.I.; Fessenden, T.J.; Keefe, D.; Kim, C.H.; Meuth, H.
1988-06-01
An experimental induction linac, called MBE-4, has been constructed to demonstrate acceleration and current amplification of multiple heavy ion beams. This work is part of a program to study the use of such an accelerator as a driver for heavy ion inertial fusion. MBE-4 is 16m long and accelerates four space-charge-dominated beams of singly-charged cesium ions, in this case from 200 keV to 700 keV, amplifying the current in each beam from 10mA by a factor of nine. Construction of the experiment was completed late in 1987 and we present the results of detailed measurements of the longitudinal beam dynamics. Of particular interest is the contribution of acceleration errors to the growth of current fluctuations and to the longitudinal emittance. The effectiveness of the longitudinal focusing, accomplished by means of the controlled time dependence of the accelerating fields, is also discussed. 4 refs., 5 figs., 1 tab
High brightness K+ ion source for heavy ion fusion linear induction accelerators
Henestroza, E.; Eylon, S.; Chupp, W.; Rutkowski, H.
1992-01-01
Low emittance, high current, singly charged potassium thermionic ion sources are being developed for the Induction Linac System Experiment injector, ILSE. The ILSE, now in study at LBL, will address the physics issues of particle beams in a heavy ion fusion driver scenario. The K + ion beam considered is emitted thermionically into a diode gap from alumino-silicate layers (zeolite) coated on a porous tungsten cup. The Single Beam Transport Experiment (SBTE) 120keV cesium source was redesigned and modified with the aid of an ion optics and gun design program (EGUN) to enable the evaluation of the K + source performance at high extraction currents of about 80mA from a one inch diameter source. The authors report on the source fabrication technique and performance, including total current and current density profile measurements using Faraday cups, phase space distributions using the double slit scanning technique, and source emitting surface temperature dependence on heating power using a wire pyrometer
Mellah HACEN
2012-08-01
Full Text Available The induction machine, because of its robustness and low-cost, is commonly used in the industry. Nevertheless, as every type of electrical machine, this machine suffers of some limitations. The most important one is the working temperature which is the dimensioning parameter for the definition of the nominal working point and the machine lifetime. Due to a strong demand concerning thermal monitoring methods appeared in the industry sector. In this context, the adding of temperature sensors is not acceptable and the studied methods tend to use sensorless approaches such as observators or parameters estimators like the extended Kalman Filter (EKF. Then the important criteria are reliability, computational cost ad real time implementation.
Ion-hose instability in a long-pulse linear induction accelerator
Thomas C. Genoni
2003-03-01
Full Text Available The ion-hose instability is a transverse electrostatic instability which occurs on electron beams in the presence of a low-density ion channel. It is a phenomenon quite similar to the interaction between electron clouds and proton or positron beams in high-energy accelerators and storage rings. In the DARHT-2 accelerator, the 2-kA, 2-μs beam pulse produces an ion channel through impact ionization of the residual background gas (10^{-7}–10^{-6} torr. A calculation of the linear growth by Briggs indicates that the instability could be strong enough to affect the radiographic application of DARHT, which requires that transverse oscillations be small compared to the beam radius. We present semianalytical theory and 3D particle-in-cell simulations (using the Lsp code of the linear and nonlinear growth of the instability, including the effects of the temporal change in the ion density and spatially decreasing beam radius. We find that the number of e-foldings experienced by a given beam slice is given approximately by an analytic expression using the local channel density at the beam slice. Hence, in the linear regime, the number of e-foldings increases linearly from head to tail of the beam pulse since it is proportional to the ion density. We also find that growth is strongly suppressed by nonlinear effects at relatively small oscillation amplitudes of the electron beam. This is because the ion oscillation amplitude is several times larger than that of the beam, allowing nonlinear effects to come into play. An analogous effect has recently been noted in electron-proton instabilities in high-energy accelerators and storage rings. For DARHT-2 parameters, we find that a pressure of ≤1.5×10^{-7} torr is needed to keep the transverse beam oscillation amplitude less than about 20% of the rms beam radius.
Kikuma, T.; Tomita, M.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)
1999-11-10
For the purpose of we examining the effect of characteristics and ac loss under real machine operating environment of the alternating current superconductivity winding for a realization of the superconductive AC machine vessel, cylindrical shortness first linear guiding motor which used NbTi/CuNi superconducting cable for the primary winding was produced experimentally. The coil number was increased from 6 in 14 this time, and the optimization of the primary current was done, and the improvement on characteristics was attempted. Here, starting torque characteristics, quenching detection protection control circuit are reported. (NEDO)
Fernandes Neto, Tobias Rafael
2012-06-28
guide way (induction rail or stationary magnets), and the energy and information should be transmitted contactless to the active vehicle. Regarding the features of the material handling application, the short or long primary topology can be used. Short primary linear drives on passive track are advantageous in material handling applications, where high precision, moderate dynamic, very long track and closed paths are required. Nevertheless, depending on the requirements of the section, the costs can be reduced considerably by using a simple induction rail at the long transporting sections, instead of permanent magnets on the track. Therefore, in this thesis a combined operation of permanent magnet linear synchronous motor (PMLSM) and linear induction motor (LIM) is applied to operate the short primary as vehicle, avoiding adjustment or releasing of the material during the drive cycle. In summary, the passive track will consist of two section types: a high thrust force section (processing station) with PMLSM and a low thrust force section with LIM (transporting section). To the author's knowledge, using two operation modes (PMLSM / LIM) in the same drive is a new approach. A theoretical and experimental study was conducted to assess the feasibility of employing the short primary linear motor for a flexible manufacturing system, in which a contactless energy transmission provides the basic power and an ultracapacitor (UC) storage system provides the peak power. The system uses a bidirectional DC-DC converter between the ultracapacitor bank and the DC-link, to make sure that the ultracapacitor can store the braking energy and supply the peak power demanded by the active vehicle. A control strategy has been developed for controlling the ultracapacitor to deliver the peak of power, to charge, to protect against overvoltage and to recover the energy generated when the vehicle is braking. A control strategy for the transition between the two operation modes (PMLSM / LIM
Eastham, A. R.; Katz, R. M.
1980-09-01
Two test programs have been conducted to evaluate the performance of a single-sided linear induction motor with a squirrel-cage reaction rail and with a solid steel reaction rail. A 1.73-m-long six-pole stator interacted with the rails mounted on the rim of a 7.6-m-diam wheel. A 64-channel data acquisition system allowed tests to be performed over a wide range of operating conditions at speeds up to 20 m/sec. Typical test results which compare and contrast the mechanical, electrical and magnetic behavior of the SLIMs are presented. The test data are being used to assess the SLIM as an integrated suspension/propulsion system and for other transportation applications.
Yu Haijun; Zhu Jun; Chen Nan; Xie Yutong; Jiang Xiaoguo; Jian Cheng
2010-01-01
Positive ions released from x-ray converter target impacted by electron beam of millimeter spot size can be trapped and accelerated in the incident beam's potential well. As the ions move upstream, the beam will be pinched first and then defocused at the target. Four Faraday cups are used to collect backstreaming ions produced at the bremsstrahlung converter target in Dragon-I linear induction accelerator (LIA). Experimental and theoretical results show that the backstreaming positive ions density and velocity are about 10 21 /m 3 and 2-3 mm/μs, respectively. The theoretical and experimental results of electron beam envelope with ions and without ions are also presented. The discussions show that the backstreaming positive ions will not affect the electron beam focusing and envelope radius in Dragon-I LIA.
Electron beam dynamics in the long-pulse, high-current DARHT-II linear induction accelerator
Ekdahl, Carl A.; Abeyta, Epifanio O.; Aragon, Paul; Archuleta, Rita; Cook, Gerald; Dalmas, Dale; Esquibel, Kevin; Gallegos, Robert A.; Garnett, Robert; Harrison, James F.; Johnson, Jeffrey B.; Jacquez, Edward B.; Mccuistian, Brian T.; Montoya, Nicholas A.; Nath, Subrato; Nielsen, Kurt; Oro, David; Prichard, Benjamin; Rowton, Lawrence; Sanchez, Manolito; Scarpetti, Raymond; Schauer, Martin M.; Seitz, Gerald; Schulze, Martin; Bender, Howard A.; Broste, William B.; Carlson, Carl A.; Frayer, Daniel K.; Johnson, Douglas E.; Tom, C.Y.; Williams, John; Hughes, Thomas; Anaya, Richard; Caporaso, George; Chambers, Frank; Chen, Yu-Jiuan; Falabella, Steve; Guethlein, Gary; Raymond, Brett; Richardson, Roger; Trainham, C.; Watson, Jim; Weir, John; Genoni, Thomas; Toma, Carsten
2009-01-01
The DARHT-II linear induction accelerator (LIA) now accelerates 2-kA electron beams to more than 17 MeV. This LIA is unique in that the accelerated current pulse width is greater than 2 microseconds. This pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. The long risetime of the 6-cell injector current pulse is 0.5 (micro)s, which can be scraped off in a beam-head cleanup zone before entering the 68-cell main accelerator. We discuss our experience with tuning this novel accelerator; and present data for the resulting beam transport and dynamics. We also present beam stability data, and relate these to previous stability experiments at lower current and energy.
V. Jegathesan
2017-11-01
Full Text Available This paper presents an efficient and reliable Genetic Algorithm based solution for Selective Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. Determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. Many methods are available to eliminate the higher order harmonics and it can be easily removed. But the greatest challenge is to eliminate the lower order harmonics and this is successfully achieved using Genetic Algorithm without using Dual transformer. Simulations using MATLABTM and Powersim with experimental results are carried out to validate the solution. The experimental results show that the harmonics up to 13th were totally eliminated.
Myrzik, J.M.A.; Duarte, J.L.; Haardt, de P.; Vissers, J.
2002-01-01
An application of the transformer-assisted PWM zero-voltage switching pole inverter (TRAP) is described in this paper. The TRAP is based on the auxiliary resonant commutated pole inverter (ARCP), but avoids its disadvantages. This paper describes the converter functionality and its applicability
Choi, D. B.
1999-01-01
This paper describes typical protection schemes for large-size high inertia drive motor that are generally rotor thermal limited. Difficult and variable starting conditions of the large-size high inertia drive motor and compromises in the selection and setting of the protective devices are frequently encountered. The motors that typically encounter severe starting duty and present difficulties in achieving full motor protection are reactor coolant pumps (RCPs), blowers and compressors. For difficult starting conditions that are encountered by the large-size high inertia drive motors, state-of-the-art computer based calculations are capable of providing realistic predictions of the band of margin available for applying the protective relay. Based on the analysis of starting characteristics of large-size high inertia drive motors, this paper recommends that the optimal protection scheme for high inertia drive motors for nuclear power plants can be achieved by using the voltage biased digital relay instead of a speed switch and conventional overcurrent relays. (author)
Keefe, D.
1986-07-01
The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed
Abbasian Mohsen
2013-02-01
Full Text Available Results of theoretical and experimental research on magnetic induction distribution in the air gap of a coaxially-linear synchronous motor with reciprocal motion within the pole pitch and axial and radial direction of the permanent magnets magnetization are presented.
Masuda, Hiroshi; Kanda, Yutaro; Okamoto, Yoshifumi; Hirono, Kazuki; Hoshino, Reona; Wakao, Shinji; Tsuburaya, Tomonori
2017-12-01
It is very important to design electrical machineries with high efficiency from the point of view of saving energy. Therefore, topology optimization (TO) is occasionally used as a design method for improving the performance of electrical machinery under the reasonable constraints. Because TO can achieve a design with much higher degree of freedom in terms of structure, there is a possibility for deriving the novel structure which would be quite different from the conventional structure. In this paper, topology optimization using sequential linear programming using move limit based on adaptive relaxation is applied to two models. The magnetic shielding, in which there are many local minima, is firstly employed as firstly benchmarking for the performance evaluation among several mathematical programming methods. Secondly, induction heating model is defined in 2-D axisymmetric field. In this model, the magnetic energy stored in the magnetic body is maximized under the constraint on the volume of magnetic body. Furthermore, the influence of the location of the design domain on the solutions is investigated.
Two-Step Multi-Physics Analysis of an Annular Linear Induction Pump for Fission Power Systems
Geng, Steven M.; Reid, Terry V.
2016-01-01
One of the key technologies associated with fission power systems (FPS) is the annular linear induction pump (ALIP). ALIPs are used to circulate liquid-metal fluid for transporting thermal energy from the nuclear reactor to the power conversion device. ALIPs designed and built to date for FPS project applications have not performed up to expectations. A unique, two-step approach was taken toward the multi-physics examination of an ALIP using ANSYS Maxwell 3D and Fluent. This multi-physics approach was developed so that engineers could investigate design variations that might improve pump performance. Of interest was to determine if simple geometric modifications could be made to the ALIP components with the goal of increasing the Lorentz forces acting on the liquid-metal fluid, which in turn would increase pumping capacity. The multi-physics model first calculates the Lorentz forces acting on the liquid metal fluid in the ALIP annulus. These forces are then used in a computational fluid dynamics simulation as (a) internal boundary conditions and (b) source functions in the momentum equations within the Navier-Stokes equations. The end result of the two-step analysis is a predicted pump pressure rise that can be compared with experimental data.
Silva, Izael Pereira da
1997-07-01
The possibility of verifying the inductive voltage transformer (IVT) precision class during its operational life by means of simple excitation and short circuit tests is shown. By this way, the transportation of such equipment to laboratories or factories for new calibrations is avoided. As IVT precision is function of geometric parameters and material characteristics such as winding resistivity, core permeability and others, if they do not change, there is no reason to expect modifications in the precision of the equipment. After a critical analysis, is intended to demonstrate and experimentally verify that excitation and short-circuit test are sufficient to detect any modification in the above parameters. If such alteration are not detected, it is possible to assure that the equipment maintains its specified class of precision. The Moellinger and Gewecke method is used in order to determine the actual value of turns ratio and the separate leakage reactance of primary winding. These parameters are not easily obtainable in practice. The present Brazilian Rule for IVT does not mention any method which permits the determination os such parameters. Comparison of errors obtained by the present method with those found with Schering-Alberti Bridge, showed that this methodology is effective and useful mainly when precision test equipment (such as A C relation bridge, standard transformer, standard burdens) are not available, and it is necessary to verify a transformer condition or even decide about a non-accordance between two results founded in laboratories through conventional methods. Several discussions about transformer models are also included, in particular the decomposition method, which, being essentially different from the T equivalent model, shows interesting aspects of transformer analysis. Two other points of special interest are: the critical analysis of the Moellinger and Gewecke method described at part 3.5 and its possible insertion in the NBR 6820
Lee, Kyo-Beum; Blaabjerg, Frede
2004-01-01
This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with a non-linearity compensation and disturbance observer. The nonlinear voltage distortion that is caused by communication delay and on-state voltage drop in switching...
Updating the induction module from single-pulse to double-pulses
Huang Ziping; Wang Huacen; Deng Jianjun
2002-01-01
A double-pulse Linear Induced Accelerator (LIA) module is reconstructed based on a usual simple-pulse LIA module. By changing the length of one of the cables between the inductive cell and the Blumlein pulse forming line, two induction pulses with 90 ns FWHM and 150 kV pulse voltage are generated by the ferrite cores inductive cell. The interval time of the pulses is adjustable by changing the lengths of the cable
High voltage MOSFET switching circuit
McEwan, Thomas E.
1994-01-01
The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.
Jalalifar Mehran
2007-01-01
Full Text Available In this paper using adaptive backstepping approach an adaptive rotor flux observer which provides stator and rotor resistances estimation simultaneously for induction motor used in series hybrid electric vehicle is proposed. The controller of induction motor (IM is designed based on input-output feedback linearization technique. Combining this controller with adaptive backstepping observer the system is robust against rotor and stator resistances uncertainties. In additional, mechanical components of a hybrid electric vehicle are called from the Advanced Vehicle Simulator Software Library and then linked with the electric motor. Finally, a typical series hybrid electric vehicle is modeled and investigated. Various tests, such as acceleration traversing ramp, and fuel consumption and emission are performed on the proposed model of a series hybrid vehicle. Computer simulation results obtained, confirm the validity and performance of the proposed IM control approach using for series hybrid electric vehicle.
Bhowmik, R. N.; Vijayasri, G.
2015-06-01
We have studied current-voltage (I-V) characteristics of α-Fe1.64Ga0.36O3, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔVP) 0.345(± 0.001) V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (˜500-700%), magnetoresistance (70-135 %) and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.
Bhowmik, R. N., E-mail: rnbhowmik.phy@pondiuni.edu.in; Vijayasri, G. [Department of Physics, Pondicherry University, R.Venkataraman Nagar, Kalapet, Puducherry - 605 014 (India)
2015-06-15
We have studied current-voltage (I-V) characteristics of α-Fe{sub 1.64}Ga{sub 0.36}O{sub 3}, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔV{sub P}) 0.345(± 0.001) V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (∼500-700%), magnetoresistance (70-135 %) and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.
R. N. Bhowmik
2015-06-01
Full Text Available We have studied current-voltage (I-V characteristics of α-Fe1.64Ga0.36O3, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔVP 0.345(± 0.001 V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (∼500-700%, magnetoresistance (70-135 % and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.
Warwick, A.I.; Gough, D.E.; Keefe, D.; Meuth, H.
1988-10-01
We report on the implementation of a second schedule of acceleration and current amplification in MBE-4. Control of the beam current within the bunch is improved over that in the first schedule by the addition of several small amplitude induction pulsers to compensate for acceleration errors and to control the ends of the bunch. Measurements of the longitudinal and transverse emittance are presented. 5 refs., 3 figs., 1 tab
Warwick, A.I.; Gough, D.E.; Keefe, D.; Meuth, H.
1989-01-01
The authors report on the implementation of a second schedule of acceleration and current amplification in MBE-4. Control of the beam current within the bunch is improved over that in the first schedule by the addition of several small amplitude induction pulsers to compensate for acceleration errors and to control the ends of the bunch. Measurements of the longitudinal and transverse emittance are presented. 5 refs., 3 figs., 1 tab
Abubakirov, E.V.; Arkhipov, O.V.; Bobyleva, L.V.
1990-01-01
The section of linear induction accelerator (LIA) with a strong guiding magnetic field (up to 1.5 T), with output beam power up to 2 GW and beam pulse duration 60 ns is created and investigated by experiment. The beam energy gain is equal to 10 keV/sm with explosive emission is used; the large length of the beam propagation (1.5 m) without spolling of the beam with high beam energy gain has been established. The microwave radiation power about 30-100 MW has achieved from relativistic Cherenkov travelling wave tube with high exponential gain on the basis of LIA and high-current diode
Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.
1998-01-01
A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.
Lee, Kyo-Beum; Blaabjerg, Frede
2004-01-01
This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with non-linearity compensation. The nonlinear voltage distortion that is caused by commutation delay and on-state voltage drop in switching device is corrected by a new...
Pittini, Riccardo; Zhang, Zhe; Ouyang, Ziwei
2012-01-01
on winding resistance and leakage inductances which represent the main concerns related to low-voltage high-current applications. The PCB winding design has a one to one turn ratio with no interleaving between primary and secondary windings. The main goal was to determine if ER planar core could provide...... a significant advantage in terms of winding losses compared to planar E cores. Results from finite element analysis highlight that low frequency winding resistance is lower for the ER core since it is dominated by the lower mean turn length however, as the AC-resistance becomes dominating the winding eddy...... more realistic results when computing the winding AC-resistance....
Sifeu Takougang Kingni
2017-01-01
Full Text Available A linear resistive-capacitive-inductance shunted junction (LRCLSJ model obtained by replacing the nonlinear piecewise resistance of a nonlinear resistive-capacitive-inductance shunted junction (NRCLSJ model by a linear resistance is analyzed in this paper. The LRCLSJ model has two or no equilibrium points depending on the dc bias current. For a suitable choice of the parameters, the LRCLSJ model without equilibrium point can exhibit regular and fast spiking, intrinsic and periodic bursting, and periodic and chaotic behaviors. We show that the LRCLSJ model displays similar dynamical behaviors as the NRCLSJ model. Moreover the coexistence between periodic and chaotic attractors is found in the LRCLSJ model for specific parameters. The lowest order of the commensurate form of the no equilibrium LRCLSJ model to exhibit chaotic behavior is found to be 2.934. Moreover, adaptive finite-time synchronization with parameter estimation is applied to achieve synchronization of unidirectional coupled identical fractional-order form of chaotic no equilibrium LRCLSJ models. Finally, a cryptographic encryption scheme with the help of the finite-time synchronization of fractional-order chaotic no equilibrium LRCLSJ models is illustrated through a numerical example, showing that a high level security device can be produced using this system.
High power switches for ion induction linacs
Humphries, S.; Savage, M.; Saylor, W.B.
1985-01-01
The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystronlike interaction with the accelerating cavities, leading to enhanced momentum spread. In this paper, we describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4
High power switches for ion induction linacs
Humphries, S. Jr.; Savage, M.; Saylor, W.B.
1985-01-01
The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystron-like interaction with the accelerating cavities leading to enhanced momentum spread. In this paper, the author describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4
Ahmadzadeh, Soheil; Markadeh, Gholamreza Arab; Blaabjerg, Frede
2017-01-01
In this study, a sliding mode-based controller is designed for regulating the output voltage of a high step-up DC-DC converter with three coupled inductors called Y-source impedance network. As Y-source converter can provide a very high boost at a lower shoot-through duty cycle of the switch...
Ye. V. Dmitriev
2007-01-01
Full Text Available Analysis of the Over-Voltage Limiter (OVL influence on electromagnetic high-frequency over-voltages at commutations with isolators of unloaded sections of wires and possibility of application of a frequency-dependent resistor in case of necessity to facilitate OVL operation conditions is provided in the paper.It is shown that it is necessary to take into account characteristics of OVL by IEEE circuit and its modifications at computer modeling of high-frequency over-voltages.
Rahul, Arun; Pramanick, Sumit; Kaarthik, R. Sudharshan
2017-01-01
In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage of the in......In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage...... of the inverter can be increased from 0.577 to 0.637Vdc without increasing the dc bus voltage and without exceeding the induction motor voltage rating. This new technique makes use of cascaded inverter pole voltage redundancy and property of the space vector structure for its operation. Using this, the induction...
Oyegoke, B.S. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics
1997-12-31
This paper presents the results of surge distribution tests performed on a stator of a 6 kV induction motor. The primary aim of these tests was to determine the wave propagation properties of the machine winding fed via cables of different lengths. Considering the measured resorts, conclusions are derived regarding the effect of cable length on the surge distribution within the stator winding of an ac motor. (orig.) 15 refs.
Kikuma, T.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)
2000-05-29
For the purpose of examining the characteristics (effect of stability and ac loss by the higher harmonic wave etc.) of an alternating current superconductivity winding under a real machine operating environment of the super-conductive AC machine vessel, authors produced a cylindrical shortness first linear guiding motor (SCLIM) which used the NbTi/CuNi super-conducting cable for the first excitation winding experimentally. In this study, the evaluation of the start up thrust and operation confirmation of the quenching detection protection circuit were carried out using the produced SCLIM. In the quenching detection protection control circuit, the first excitation winding was divided into an internal layer and an outer layer, and both layers were excited in the 2 layer division and a quenching detection protection circuit was installed on the 2 layers respectively. The circuit of a part of fact by this of the phase in which the quench was generated and observed was cut off, and the operation would be able to be continued in part of the remainder of the phase and other two phases. Here, it is to cut off the quenched phase from the circuit, when the phase current becomes zero, and the other effect on the phase is held as small as possible. (NEDO)
Michelle A Krupna-Gaylord
Full Text Available The capacity for Borrelia burgdorferi to cause disseminated infection in humans or mice is associated with the genotype of the infecting strain. The cytokine profiles elicited by B. burgdorferi clinical isolates of different genotype (ribosomal spacer type groups were assessed in a human PBMC co-incubation model. RST1 isolates, which are more frequently associated with disseminated Lyme disease in humans and mice, induced significantly higher levels of IFN-α and IFN-λ1/IL29 relative to RST3 isolates, which are less frequently associated with disseminated infection. No differences in the protein concentrations of IFN-γ, IL-1β, IL-6, IL-8, IL-10 or TNF-α were observed between isolates of differing genotype. The ability of B. burgdorferi to induce type I and type III IFNs was completely dependent on the presence of linear plasmid (lp 36. An lp36-deficient B. burgdorferi mutant adhered to, and was internalized by, PBMCs and specific dendritic cell (DC subsets less efficiently than its isogenic B31 parent strain. The association defect with mDC1s and pDCs could be restored by complementation of the mutant with the complete lp36. The RST1 clinical isolates studied were found to contain a 2.5-kB region, located in the distal one-third of lp36, which was not present in any of the RST3 isolates tested. This divergent region of lp36 may encode one or more factors required for optimal spirochetal recognition and the production of type I and type III IFNs by human DCs, thus suggesting a potential role for DCs in the pathogenesis of B. burgdorferi infection.
Ferguson, Jill Wisnewski; Houk, R.S.
2006-01-01
Common polyatomic ions (ArO + , NO + , H 2 O + , H 3 O + , Ar 2 + , ArN + , OH + , ArH + , O 2 + ) in inductively coupled plasma-mass spectrometry (ICP-MS) are identified using high mass resolution and studied using kinetic gas temperatures (T gas ) determined from a dissociation reaction approach. Methods for making accurate mass measurements, confirming ion identifications, and correcting for mass bias are discussed. The effects of sampler and skimmer cone composition and extraction voltage on polyatomic ion formation are also explored. Neutral species densities at several locations in the extraction interface are estimated and the corresponding effects of the T gas value are calculated. The results provide information about the origins of background ions and indicate possible locations for their formation or removal
Kavitha, A.; Kannan, R. [Department of Physics, University College of Engineering, Anna University, Dindugal-624622 (India); Subramanian, N. Sankara [Department of Physics, Thiagarajar College of Engineering, Madurai -625015, Tamilnadu (India); Loganathan, S. [Ion Plating, Titan Industries Ltd., Hosur - 635126, Tamilnadu (India)
2014-04-24
Zirconium nitride thin films have been prepared on stainless steel substrate (304L grade) by reactive cylindrical magnetron sputtering method with Gas Ion Source (GIS) and bias voltage using optimized coating parameters. The structure and surface morphologies of the ZrN films were characterized using X-ray diffraction, atomic microscopy and scanning electron microscopy. The adhesion property of ZrN thin film has been increased due to the GIS. The coating exhibits better adhesion strength up to 10 N whereas the ZrN thin film with bias voltage exhibits adhesion up to 500 mN.
Kang, Bongmun; Yoon, Ho-Sung
2015-02-01
Recently, microalgae was considered as a renewable energy for fuel production because its production is nonseasonal and may take place on nonarable land. Despite all of these advantages, microalgal oil production is significantly affected by environmental factors. Furthermore, the large variability remains an important problem in measurement of algae productivity and compositional analysis, especially, the total lipid content. Thus, there is considerable interest in accurate determination of total lipid content during the biotechnological process. For these reason, various high-throughput technologies were suggested for accurate measurement of total lipids contained in the microorganisms, especially oleaginous microalgae. In addition, more advanced technologies were employed to quantify the total lipids of the microalgae without a pretreatment. However, these methods are difficult to measure total lipid content in wet form microalgae obtained from large-scale production. In present study, the thermal analysis performed with two-step linear temeperature program was applied to measure heat evolved in temperature range from 310 to 351 °C of Nostoc sp. KNUA003 obtained from large-scale cultivation. And then, we examined the relationship between the heat evolved in 310-351 °C (HE) and total lipid content of the wet Nostoc cell cultivated in raceway. As a result, the linear relationship was determined between HE value and total lipid content of Nostoc sp. KNUA003. Particularly, there was a linear relationship of 98% between the HE value and the total lipid content of the tested microorganism. Based on this relationship, the total lipid content converted from the heat evolved of wet Nostoc sp. KNUA003 could be used for monitoring its lipid induction in large-scale cultivation. Copyright © 2014 Elsevier Inc. All rights reserved.
Vargese Jegathesan
2008-01-01
Full Text Available This paper presents an efficient and reliable Genetic Algorithm-based solution for Specific Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. The determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. In this proposed method, harmonics up to 17th are eliminated using Genetic Algorithm without using Dual transformer. Simulations using Matlab 7.0 and PSIM 6.1 are carried out so as to validate the solution.
Carvajal, Francisco Antonio; Ramirez, Jose Manuel; Arcos, Luis Fernando [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)
1999-07-01
The induction motors of low, medium and high voltage are the electrical equipment of greatest application in industry. The importance which they have in the different productive processes does necessary to assure its operative continuity. The anticipated detection of a possible cause of fault allows to plan, with maintenance aims, the programmed removal of the motor. In this article are presented the results of the activities nowadays performed by Management of Electrical Equipment of the Instituto de Investigaciones Electricas (IIE) for the development and application of online diagnosis techniques for induction motors up to 13.8 kV. [Spanish] Los motores de induccion de baja, mediana y alta tension son los equipos eletricos de mayor aplicacion en la industria. La importancia que tienen en los diferentes procesos productivos hace necesario asegurar su continuidad operativa. La deteccion anticipada de una posible causa de falla permite planear, con fines de mantenimiento, la remocion programada del motor. En este articulo se presentan los resultados de las actividades que realiza actualmente la Gerencia de equipos Electricos del Instituto de investigaciones Electricas (IIE) para el desarrollo y la aplicacion de tecnicas de diagnostico en linea para motores de induccion de hasta 13.8 kV.
Vladimir Sousa Santos
2013-06-01
Full Text Available En los sistemas eléctricos de potencia es muy común encontrar problemas de calidad de la energía. La circulación de armónicos de tiempo en las redes de suministro eléctrico industrial junto al desbalance de tensión, afecta considerablemente el funcionamiento de los motores asincrónicos trifásicos y dificulta su caracterización energética. Existen diferentes métodos in situ para la estimación de la eficiencia de los motores. Sin embargo, ninguno ha sido lo suficientemente preciso para el análisis bajo la influencia de armónicos, desviaciones y desbalance de tensión. En este trabajo se presenta un procedimiento basado en los circuitos equivalentes, con segregación de pérdidas y empleando un Algoritmo de Forraje Bacterial (AFB, que permite determinar en condiciones de campo y con baja invasividad, la eficiencia energética de motores asincrónicos trabajando en las condiciones señaladas. El método se probó satisfactoriamente en un motor de 1,5 kW alimentado con niveles significativos de desbalance y armónicos de tensión.In electric supply systems it is very common to find problems of power quality. The time harmonic flow in industrial electrical grids with voltage deviations and unbalance, significantly affects three phase induction motor operation and makes difficult energy characterization. There are different methods for in situ estimation of motors efficiency. However, none of them have been sufficiently precise for the analysis under non-sinusoidal, deviated and unbalanced voltage conditions. This paper presents a method based on the equivalent circuits, with losses segregation and using Bacterial Foraging Algorithm (BFA. It allows determining under field conditions and low invasiveness, energy efficiency of induction motors operating under the before mentioned conditions. This method was tested successfully on a 1,5 kW motor, fed with significant levels of unbalance and voltage harmonics.
Vladimir Sousa Santos
2013-06-01
Full Text Available En los sistemas eléctricos de potencia es muy común encontrar problemas de calidad de la energía. La circulación de armónicos de tiempo en las redes de suministro eléctrico industrial junto al desbalance de tensión, afecta considerablemente el funcionamiento de los motores asincrónicos trifásicos y dificulta su caracterización energética. Existen diferentes métodos in situ para la estimación de la eficiencia de los motores. Sin embargo, ninguno ha sido lo suficientemente preciso para el análisis bajo la influencia de armónicos, desviaciones y desbalance de tensión. En este trabajo se presenta un procedimiento basado en los circuitos equivalentes, con segregación de pérdidas y empleando un Algoritmo de Forraje Bacterial (AFB, que permite determinar en condiciones de campo y con baja invasividad, la eficiencia energética de motores asincrónicos trabajando en las condiciones señaladas. El método se probó satisfactoriamente en un motor de 1,5 kW alimentado con niveles significativos de desbalance y armónicos de tensión. In electric supply systems it is very common to find problems of power quality. The time harmonic flow in industrial electrical grids with voltage deviations and unbalance, significantly affects three phase induction motor operation and makes difficult energy characterization. There are different methods for in situ estimation of motors efficiency. However, none of them have been sufficiently precise for the analysis under non-sinusoidal, deviated and unbalanced voltage conditions. This paper presents a method based on the equivalent circuits, with losses segregation and using Bacterial Foraging Algorithm (BFA. It allows determining under field conditions and low invasiveness, energy efficiency of induction motors operating under the before mentioned conditions. This method was tested successfully on a 1,5 kW motor, fed with significant levels of unbalance and voltage harmonics.
Voltage Quality of Grid Connected Wind Turbines
Chen, Zhe; Blaabjerg, Frede; Sun, Tao
2004-01-01
Grid connected wind turbines may cause quality problems, such as voltage variation and flicker. This paper discusses the voltage variation and flicker emission of grid connected wind turbines with doubly-fed induction generators. A method to compensate flicker by using a voltage source converter...
Brainard, John P [Albuquerque, NM; Christenson, Todd R [Albuquerque, NM
2009-11-03
A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.
Bi, Ke; Sui, Ning; Zhang, Liquan; Wang, Yinghui, E-mail: yinghui-wang@outlook.com; Liu, Qinghui, E-mail: liuqinghui@jlu.edu.cn; Tan, Mingrui [Jilin University, Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China); Zhou, Qiang [Jilin University, Key Laboratory of Superhard Materials, College of Physics (China); Zhang, Hanzhuang, E-mail: zhanghz@jlu.edu.cn [Jilin University, Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics (China)
2016-12-15
The role of ZnS shell on the photo-physical properties within CuInS{sub 2}/ZnS quantum dots (QDs) is carefully studied in optoelectronic devices. Linearly increasing voltage technique has been employed to investigate the charge carrier dynamics of both CuInS{sub 2} and CuInS{sub 2}/ZnS QDs films. This study shows that charge carriers follow a similar behavior of monomolecular recombination in this film, with their charge transfer rate correlates to the increase of applied voltage. It turns out that the ZnS shell could affect the carrier diffusion process through depressing the trapping states and would build up a potential barrier.
Zhu, Bao; Liu, Wen-Jun; Wei, Lei; Zhang, David Wei; Jiang, Anquan; Ding, Shi-Jin, E-mail: sjding@fudan.edu.cn [State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433 (China)
2015-07-07
Excellent voltage linearity of metal-insulator-metal (MIM) capacitors is highly required for next generation radio frequency integration circuits. In this work, employing atomic layer deposition technique, we demonstrated how the voltage linearity of MIM capacitors was modulated by adding different thickness of SiO{sub 2} layer to the nano-stack of Al{sub 2}O{sub 3}/ZrO{sub 2}. It was found that the quadratic voltage coefficient of capacitance (α) can be effectively reduced from 1279 to −75 ppm/V{sup 2} with increasing the thickness of SiO{sub 2} from zero to 4 nm, which is more powerful than increasing the thickness of ZrO{sub 2} in the Al{sub 2}O{sub 3}/ZrO{sub 2} stack. This is attributed to counteraction between the positive α for Al{sub 2}O{sub 3}/ZrO{sub 2} and the negative one for SiO{sub 2} in the MIM capacitors with Al{sub 2}O{sub 3}/ZrO{sub 2}/SiO{sub 2} stacks. Interestingly, voltage-polarity dependent conduction behaviors in the MIM capacitors were observed. For electron bottom-injection, the addition of SiO{sub 2} obviously suppressed the leakage current; however, it abnormally increased the leakage current for electron top-injection. These are ascribed to the co-existence of shallow and deep traps in ZrO{sub 2}, and the former is in favor of the field-assisted tunnelling conduction and the latter contributes to the trap-assisted tunnelling process. The above findings will be beneficial to device design and process optimization for high performance MIM capacitors.
Foss, M.H.
1981-01-01
Several accelerator-based intense neutron sources have been constructed or designed by various laboratories around the world. All of these facilities have a common scheme of a linac and synchrotron or accumulator ring, and the system produces the proton energy of 500 to 1000 MeV. The average beam currents range from a few mA to a few hundred mA. The protons are then used to generate high-flux neutrons by spallation out of heavy-metal targets. In a synchrotron system, the protons are already bunched, and thus the pulse rate of the neutron beam is that of the repetition rate of the synchrotron. For an accumulator system, the pulse rate is determined by the extraction repetition rate of the accumulator. We have conceptually designed a new system that uses a linear-induction accelerator which can be operated for an average beam current up to a few mA with a repetition rate up to 100 Hz. The details of the design will be given
Almeida, Antonio Tadeu L. de; Sa, Jocelio Souza de; Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil)
1988-12-31
This work provides several expressions for determination of the losses in inductions motors of slip-rings in steady state; always as possible, the catalogue data of national manufacturers are used. In addition, the influence of the speed control through the combined variation of the stator voltage and rotor resistance in these losses is analysed. (author) 7 refs., 5 figs.
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
M.G Macri
2012-04-01
Full Text Available Este documento presenta los resultados del estudio realizado de la descomposición wavelet multinivel 1D de las señales perturbadas del par electromagnético y de la velocidad del eje del motor trifásico de inducción, cuando este es sometido a diferentes tipologías de huecos de tensión según la caracterización ABC, Bollen (2000. Los huecos de tensión trifásicos (3 variables son analizados indirectamente en el efecto producido en una variable perturbada (el par electromagnético o la velocidad del eje que contiene indirectamente información del tipo de hueco de tensión trifásico producido en el estator. El estudio analiza el efecto de los siete diferentes tipos de huecos de tensión, considerando también la influencia de la duración y tensión retenida. Para cada caso se obtiene un vector cuyos elementos son los niveles de energía wavelet en los distintos niveles de descomposición de la variable analizada, mostrando que la forma en que se distribuye la energía de la señal 1D en los distintos niveles de descomposición establece una firma única para cada caso. Esta forma de descripción de los huecos de tensión producidos en el estator, basada en la descomposición multinivel de una variable perturbada, reduce la cantidad de variables a analizar y permite posteriormente la clasificación de las perturbaciones empleando técnicas de inteligencia artificial; es ventajosa pues el almacenamiento de los vectores de niveles de energía de aproximación en las bases de datos emplea menor cantidad de espacio que la necesaria para una señal temporal, y empleando una DWT reversible es posible, además, reconstruir la variable de estado temporal.This document presents the study results of the wavelet 1D multi-level decomposition of perturbed electromagnetic torque and shaft speed signals, of the three-phase induction motor, when it is subjected to different types of voltage sags, as characterization ABC, Bollen (2000. The three
Torres Montalvo, Emmanuel
2006-09-15
Although only one part of the mini/micro hydraulic power has been exploited in our country, this type of electric energy generation can be considered as a visible way of electricity generation, mainly related to the ecological, economical and social aspects. The impact that these power plants can have in the regions in which they are installed is always positive: cost energy cost reduction, economical spills and mainly a social welfare. The electric energy is one of the pillars for the economical development of a country and provides a better life quality. Nowadays the research and the technology oriented to the operation and control of the micro/mini power plants has awaken the interest of many researchers in several countries of the world as China, India, Canada, and USA to mention some of them. The induction generator plays a crucial role in the uses of these technologies. The work of Basset and Potter in 1935 is the angular stone over the possibility of generating energy making use of the induction machine and a capacitors bank connected to the machine terminals. This configuration is known as induction auto-excited generator (GIAE). Several investigations have been realized that deal about the functioning principle and the dynamic behavior a GIAE, which can supply electric power in remote isolated regions. In the existing literature have been proposed control strategies to offer voltage regulations and/or frequency into the acceptable range. Some of these control strategies present problems such a demand of a reactive power, harmonics injections in the system, the control circuits are complicated, expensive and voluminous and prone to fail. This paper realizes an analysis of the necessary and sufficient conditions so that an induction machine can operate as GIAE. The corresponding curves are presented for each studied case. The dynamic behavior of the voltage and the frequency generated by the GIAE are studied in detail, which is a contribution to the existing
Self-tuning Torque Control of Induction Motors for High Performance Applications
Rasmussen, Henrik
-link voltage a non-linear model of the inverter giving the relation between turn-on times and voltages is developed. A dynamic model of the induction motor based on space phasors is described. The model in a reference frame fixed to the rotor magnetizing current is analyzed in detail and extended with a model......: · To analyze and develop strategies for torque control of induction motors well suited for automatic tuning. · To analyze and develop methods for automatic tuning of the applied controllers. · To develop robust methods for adaptive field oriented control. · To test the final concept on different motors...... for magnetic saturating. The parameters in this non-linear model of the motor and inverter are determined by impressing some special designed stator voltage signals and measuring the stator currents. A s something new in this context a robust current controller is determined by relay experiment before starting...
Voltage Dependence of Supercapacitor Capacitance
Szewczyk Arkadiusz
2016-09-01
Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.
A Robust Control Scheme for Medium-Voltage-Level DVR Implementation
Blaabjerg, Frede; Loh, Poh Chiang; Li, Yun Wei
2007-01-01
of Hinfin controller weighting function selection, inner current loop tuning, and system disturbance rejection capability is presented. Finally, the designed control scheme is extensively tested on a laboratory 10-kV MV-level DVR system with varying voltage sag (balanced and unbalanced) and loading (linear....../nonlinear load and induction motor load) conditions. It is shown that the proposed control scheme is effective in both balanced and unbalanced sag compensation and load disturbance rejection, as its robustness is explicitly specified....
Handbook on linear motor application
1988-10-01
This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.
Rectangular waveform linear transformer driver module design
Zhao Yue; Xie Weiping; Zhou Liangji; Chen Lin
2014-01-01
Linear Transformer Driver is a novel pulsed power technology, its main merits include a parallel LC discharge array and Inductive Voltage Adder. The parallel LC discharge array lowers the whole circuit equivalent inductance and the Inductive Voltage Adder unites the modules in series in order to create a high electric field grads, meanwhile, restricts the high voltage in a small space. The lower inductance in favor of LTD output a fast waveform and IVA confine high voltage in secondary cavity. In recently, some LTD-based pulsed power system has been development yet. The usual LTD architecture provides damped sine shaped output pulses that may not be suitable in flash radiography, high power microwave production, z-pinch drivers, and certain other applications. A more suitable driver output pulse would have a flat or inclined top (slightly rising or falling). In this paper, we present the design of an LTD cavity that generates this type of the output pulse by including within its circular array some number of the harmonic bricks in addition to the standard bricks according to Fourier progression theory. The parallel LC discharge array circuit formula is introduced by Kirchhoff Law, and the sum of harmonic is proofed as an analytic result, meanwhile, rationality of design is proved by simulation. Varying gas spark discharge dynamic resistance with harmonic order and switches jitter are analyzed. The results are as following: The more harmonic order is an approach to the ideal rectangular waveform, but lead to more system complexity. The capacity decreases as harmonic order increase, and gas spark discharge dynamic resistance rises with the capacity. The rising time protracts and flat is decay or even vanishes and the shot to shot reproducibility is degenerate as the switches jitter is high. (authors)
Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor
Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman
2016-02-01
Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.
Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor
Zainal, Nurul Afiqah; Tat, Chan Sooi; Ajisman
2016-01-01
Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's output is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor. (paper)
Gonzalez, Albin Leonel
The response to different types of radiation beams of commercial imaging plates used for diagnostic computed radiography has been investigated in this work. Imaging plates are designed with a phosphor layer which after been irradiated; information is stored in the form of photostimulable luminescence (PSL) centers. Initial measurements of the dose distribution of a radioactive stent with the imaging plates showed similar results to those with radiochromic films, but with much shorter exposure time due to their higher sensitivity. In order to investigate further their response, the imaging plates were irradiated with calibrated beams from: standard beta sources, orthovoltage and Co-60 units and therapy linear accelerator. Initially it was found that the energy to create the storage centers (generation efficiency) when irradiated with the three standard beta sources (225 keV to 2.28 MeV) was the same. For the rest of the calibrated beams an in house reader system was built in order to perform the bleaching of the plates with a He-Ne laser (632.8 nm) and to measure the absolute number of the emitted PSL photons (storage centers produced). Bleaching curves were then obtained for different exposure times for each beam. From the graph of the calculated area under the bleaching curves (total number of storage center) versus the absorbed dose to the phosphor layer it was possible to calculate the energy to create the storage centers (generation efficiency) for photon and electron beams. The dose to the phosphor layer was calculated in the case of the electron beams following a scaling procedure, while in the case of the photon beams Monte Carlo simulations were performed. For the photons beams the measurement of the generation efficiency energy of 126 +/- 8% eV per PSL storage center, coincide with measurements using a different approach (˜148 eV) by previous investigators. The generation efficiency for the electron beam was 807 +/- 3% eV, no reference was found in the
Juan Miguel Astorga Gómez
2015-04-01
Full Text Available En este artículo se evalúan las armónicas individuales de tensión como función de las armónicas individuales de corriente usando los análisis estadísticos de regresión lineal simple, regresión polinomial y regresión lineal múltiple. Para la selección del modelo, se usan el coeficiente de determinación R2 y el criterio de información de Akaike (AIC. Se utiliza como caso de estudio un sistema eléctrico de un proceso minero ubicado en la región de Atacama Copiapó Chile, que ocupa la técnica de electro obtención de cobre como parte principal de su proceso productivo. Se muestran y comparan los resultados para los distintos modelos estadísticos y se discute la información de éstos para el estudio de calidad de energía. Finalmente, usando el modelo que mejor se ajusta a las mediciones de armónicas de tensión y corriente, se muestran algunas predicciones para la componente armónica dominante de tensión. This paper assesses the individual voltage harmonics as a function of the individual current harmonics using the statistical analyses of simple linear regression, polynomial regression and multiple linear regression. For model choice, the coefficient of determination R2 and Akaike information criterion (AIC are used. A mining process electrical system located in the Atacama Copiapó Chile, is used as a case study. This uses the technique copper electrowining as the main part of its production process. The results for different statistical models are shown and their information discussed for the power quality study. Finally, using the model that better fits to the measurements of voltage and current harmonics, some predictions for the dominant voltage harmonic are shown.
Inductive energy storage commutator
Gavrilov, I.M.
1987-01-01
An inductive energy storage commutator is described. The value of commutated current is up to 800 A, the voltage amplitude in the load is up to 50 kV, the working frequency is equal to 1-50 Hz, the commutated power is up to 40 MW. The commutating device comprises of the first stage commutator having two in-series connected modules of the BTSV - 800/235 high-voltage thyristor unit, the second stage commutator containing three GMI-43A parallel connected powerful pulsed triodes, a commutating capacitor, an induction coil, two supplementary high-voltage thyristor keys (20 in-series connected thyristors T2-300 (13 class)), load, control pulse shapers, thyristor keys, power supply
Measurements of Voltage Harmonics in 400 kV Transmission Network
Ryszard Pawełek
2014-06-01
Full Text Available The paper deals with the analysis of voltage harmonics measurements performed in the 400 kV transmission network. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider.
Eduardo Giraldo Suárez
2009-01-01
Full Text Available Este documento presenta la aplicación de la técnica de control no lineal clásica llamada linealización por realimentación de variables de estado. Se hace una aplicación en el motor de inducción, la variable a controlar es la velocidad del eje del motor, el sistema emplea el esquema de control vectorial para máquinas de corriente alterna desarrollado en las últimas décadas; este método es análogo a la técnica de control del motor de corriente directa. El modelo del motor de inducción se describe en el sistema de coordenadas de campo orientado del flujo de rotor y se muestra una introducción al producto y la derivada de Lie, empleados en el diseño del controlador no lineal.This articles shows the application of a classic non-linear control technique called "linearization by feedback of status variables." An application on the induction engine is made. Variable to be controlled is speed of the engine shaft. The system employs a vectorial control scheme for AC engines developed during the last decades. This is a method analogous to the DC engine control technique. Induction engine model is described in the guided field coordinate system of rotor flow. Introduction to the product and Lie derivative used for designing the non-linear controller are shown.
Holakooie, Mohammad Hosein; Ojaghi, Mansour; Taheri, Asghar
2016-01-01
This paper investigates sensorless indirect field oriented control (IFOC) of SLIM with full-order Luenberger observer. The dynamic equations of SLIM are first elaborated to draw full-order Luenberger observer with some simplifying assumption. The observer gain matrix is derived from conventional procedure so that observer poles are proportional to SLIM poles to ensure the stability of system for wide range of linear speed. The operation of observer is significantly impressed by adaptive scheme. A fuzzy logic control (FLC) is proposed as adaptive scheme to estimate linear speed using speed tuning signal. The parameters of FLC are tuned using an off-line method through chaotic optimization algorithm (COA). The performance of the proposed observer is verified by both numerical simulation and real-time hardware-in-the-loop (HIL) implementation. Moreover, a detailed comparative study among proposed and other speed observers is obtained under different operation conditions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
Theoretical analysis of magnetic sensor output voltage
Liu Haishun; Dun Chaochao; Dou Linming; Yang Weiming
2011-01-01
The output voltage is an important parameter to determine the stress state in magnetic stress measurement, the relationship between the output voltage and the difference in the principal stresses was investigated by a comprehensive application of magnetic circuit theory, magnetization theory, stress analysis as well as the law of electromagnetic induction, and a corresponding quantitative equation was derived. It is drawn that the output voltage is proportional to the difference in the principal stresses, and related to the angle between the principal stress and the direction of the sensor. This investigation provides a theoretical basis for the principle stresses measurement by output voltage. - Research highlights: → A comprehensive investigation of magnetic stress signal. → Derived a quantitative equation about output voltage and the principal stresses. → The output voltage is proportional to the difference of the principal stresses. → Provide a theoretical basis for the principle stresses measurement.
Manipulating the voltage dependence of tunneling spin torques
Manchon, Aurelien
2012-01-01
Voltage-driven spin transfer torques in magnetic tunnel junctions provide an outstanding tool to design advanced spin-based devices for memory and reprogrammable logic applications. The non-linear voltage dependence of the torque has a direct impact
Voltage-Controlled Floating Resistor Using DDCC
M. Kumngern
2011-04-01
Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.
Allen, S.L.; Scharlemann, E.T.
1993-01-01
The authors have constructed a 140-GHz free-electron laser to generate high-average-power microwaves for heating the MTX tokamak plasma. A 5.5-m steady-state wiggler (Intense Microwave, Prototype-IMP) has been installed at the end of the upgraded 60-cell ETA-II accelerator, and is configured as an FEL amplifier for the output of a 140-GHz long-pulse gyrotron. Improvements in the ETA-II accelerator include a multicable-feed power distribution network, better magnetic alignment using a stretched-wire alignment technique (SWAT), and a computerized tuning algorithm that directly minimizes the transverse sweep (corkscrew motion) of the electron beam. The upgrades were first tested on the 20-cell, 3-MeV front end of ETA-II and resulted in greatly improved energy flatness and reduced corkscrew motion. The upgrades were then incorporated into the full 60-cell configuration of ETA-II, along with modifications to allow operation in 50-pulse bursts at pulse repetition frequencies up to 5 kHz. The pulse power modifications were developed and tested on the High Average Power Test Stand (HAPTS), and have significantly reduced the voltage and timing jitter of the MAG 1D magnetic pulse compressors. The 2-3 kA, 6-7 MeV beam from ETA-II is transported to the IMP wiggler, which has been reconfigured as a laced wiggler, with both permanent magnets and electromagnets, for high magnetic field operation. Tapering of the wiggler magnetic field is completely computer controlled and can be optimized based on the output power. The microwaves from the FEL are transmitted to the MTX tokamak by a windowless quasi-optical microwave transmission system. Experiments at MTX are focused on studies of electron-cyclotron-resonance heating (ECRH) of the plasma. The authors summarize here the accelerator and pulse power modifications, and describe the status of ETA-II, IMP, and MTX operations
Allen, S.L.; Scharlemann, E.T.
1992-05-01
We have constructed a 140-GHz free-electron laser to generate high-average-power microwaves for heating the MTX tokamak plasma. A 5.5-m steady-state wiggler (intense Microwave Prototype-IMP) has been installed at the end of the upgraded 60-cell ETA-II accelerator, and is configured as an FEL amplifier for the output of a 140-GHz long-pulse gyrotron. Improvements in the ETA-II accelerator include a multicable-feed power distribution network, better magnetic alignment using a stretched-wire alignment technique (SWAT). and a computerized tuning algorithm that directly minimizes the transverse sweep (corkscrew motion) of the electron beam. The upgrades were first tested on the 20-cell, 3-MeV front end of ETA-II and resulted in greatly improved energy flatness and reduced corkscrew motion. The upgrades were then incorporated into the full 60-cell configuration of ETA-II, along with modifications to allow operation in 50-pulse bursts at pulse repetition frequencies up to 5 kHz. The pulse power modifications were developed and tested on the High Average Power Test Stand (HAPTS), and have significantly reduced the voltage and timing jitter of the MAG 1D magnetic pulse compressors. The 2-3 kA. 6-7 MeV beam from ETA-II is transported to the IMP wiggler, which has been reconfigured as a laced wiggler, with both permanent magnets and electromagnets, for high magnetic field operation. Tapering of the wiggler magnetic field is completely computer controlled and can be optimized based on the output power. The microwaves from the FEL are transmitted to the MTX tokamak by a windowless quasi-optical microwave transmission system. Experiments at MTX are focused on studies of electron-cyclotron-resonance heating (ECRH) of the plasma. We summarize here the accelerator and pulse power modifications, and describe the status of ETA-II, IMP, and MTX operations
Wrigley, Christopher James (Inventor); Hancock, Bruce R. (Inventor); Newton, Kenneth W. (Inventor); Cunningham, Thomas J. (Inventor)
2014-01-01
An analog-to-digital converter (ADC) converts pixel voltages from a CMOS image into a digital output. A voltage ramp generator generates a voltage ramp that has a linear first portion and a non-linear second portion. A digital output generator generates a digital output based on the voltage ramp, the pixel voltages, and comparator output from an array of comparators that compare the voltage ramp to the pixel voltages. A return lookup table linearizes the digital output values.
Induction generator models in dynamic simulation tools
Knudsen, Hans; Akhmatov, Vladislav
1999-01-01
For AC network with large amount of induction generators (windmills) the paper demonstrates a significant discrepancy in the simulated voltage recovery after fault in weak networks when comparing dynamic and transient stability descriptions and the reasons of discrepancies are explained...
f AQ FREQUENTLY ASKED QUESTIONS FAQ154 LABOR, DELIVERY, AND POSTPARTUM CARE Labor Induction • What is labor induction? • Why is labor induced? • What is the Bishop score? • What is “ripening ...
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...
Distributed Monitoring of Voltage Collapse Sensitivity Indices
Simpson-Porco, John W.; Bullo, Francesco
2016-01-01
The assessment of voltage stability margins is a promising direction for wide-area monitoring systems. Accurate monitoring architectures for long-term voltage instability are typically centralized and lack scalability, while completely decentralized approaches relying on local measurements tend towards inaccuracy. Here we present distributed linear algorithms for the online computation of voltage collapse sensitivity indices. The computations are collectively performed by processors embedded ...
Kraus, H.G.; Jones, J.L.
1986-01-01
The problem of non-linear superconducting magnet and electrical protection circuit system transients is formulated. To enable studying the effects of coil normalization transients, coil distortion (due to imbalanced magnetic forces), internal coil arcs and shorts, and other normal and off-normal circuit element responses, the following capabilities are included: temporal, voltage and current-dependent voltage sources, current sources, resistors, capacitors and inductors. The concept of self-mutual inductance, and the form of the associated inductance matrix, is discussed for internally shorted coils. This is a Kirchhoff's voltage loop law and Kirchhoff's current node law formulation. The non-linear integrodifferential equation set is solved via a unique hybrid finite difference/integral finite element technique. (author)
2005-01-01
A voltage regulating circuit comprising a rectifier (2) for receiving an AC voltage (Vmains) and for generating a rectified AC voltage (vrec), and a capacitor (3) connected in parallel with said rectified AC voltage for providing a DC voltage (VDC) over a load (5), characterized by a unidirectional
Capacitor blocks for linear transformer driver stages.
Kovalchuk, B M; Kharlov, A V; Kumpyak, E V; Smorudov, G V; Zherlitsyn, A A
2014-01-01
In the Linear Transformer Driver (LTD) technology, the low inductance energy storage components and switches are directly incorporated into the individual cavities (named stages) to generate a fast output voltage pulse, which is added along a vacuum coaxial line like in an inductive voltage adder. LTD stages with air insulation were recently developed, where air is used both as insulation in a primary side of the stages and as working gas in the LTD spark gap switches. A custom designed unit, referred to as a capacitor block, was developed for use as a main structural element of the transformer stages. The capacitor block incorporates two capacitors GA 35426 (40 nF, 100 kV) and multichannel multigap gas switch. Several modifications of the capacitor blocks were developed and tested on the life time and self breakdown probability. Blocks were tested both as separate units and in an assembly of capacitive module, consisting of five capacitor blocks. This paper presents detailed design of capacitor blocks, description of operation regimes, numerical simulation of electric field in the switches, and test results.
Square pulse linear transformer driver
A. A. Kim
2012-04-01
Full Text Available The linear transformer driver (LTD technological approach can result in relatively compact devices that can deliver fast, high current, and high-voltage pulses straight out of the LTD cavity without any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The usual LTD architecture [A. A. Kim, M. G. Mazarakis, V. A. Sinebryukhov, B. M. Kovalchuk, V. A. Vizir, S. N Volkov, F. Bayol, A. N. Bastrikov, V. G. Durakov, S. V. Frolov, V. M. Alexeenko, D. H. McDaniel, W. E. Fowler, K. LeCheen, C. Olson, W. A. Stygar, K. W. Struve, J. Porter, and R. M. Gilgenbach, Phys. Rev. ST Accel. Beams 12, 050402 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050402; M. G. Mazarakis, W. E. Fowler, A. A. Kim, V. A. Sinebryukhov, S. T. Rogowski, R. A. Sharpe, D. H. McDaniel, C. L. Olson, J. L. Porter, K. W. Struve, W. A. Stygar, and J. R. Woodworth, Phys. Rev. ST Accel. Beams 12, 050401 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050401] provides sine shaped output pulses that may not be well suited for some applications like z-pinch drivers, flash radiography, high power microwaves, etc. A more suitable power pulse would have a flat or trapezoidal (rising or falling top. In this paper, we present the design and first test results of an LTD cavity that generates such a type of output pulse by including within its circular array a number of third harmonic bricks in addition to the main bricks. A voltage adder made out of a square pulse cavity linear array will produce the same shape output pulses provided that the timing of each cavity is synchronized with the propagation of the electromagnetic pulse.
Venkata Lakshmi Narayana K.
2013-03-01
Full Text Available In this paper, a pressure transmitter using a modified op-amp based network for inductance measurement using a bellow as sensor has been proposed to measure the pressure and to convert pressure changes in to an electrical current which can be transmitted to a remote indicator. The change in inductance due to change in pressure is measured by an improved modified operational amplifier based network. The proposed network permits offset inductance compensation of sensing coil and also minimizes the stray capacitance between sensing coil and ground using dummy inductor whose value equal to zero level inductance of sensing coil and op-amps with high input impedance. In the first part of experiment, a modified op-amp based inductance measuring circuit has been simulated using LabVIEW (Laboratory Virtual Instrument Engineering Workbench and studied with test inductance, and in the second part, the experimentation was done by replacing the test inductance with a sensing coil fitted to bellow by means of ferromagnetic wire for the measurement of pressure. It has been observed that the variation in gauge pressure from 0 to 70 psi having linear relationship with output ac voltage in the range of 0 to 85.0 mV. Corresponding to pressure variations, the ac output voltage further converted into an electric current of 4 to 20 mA for remote indication and control purpose. The investigations have been performed to sense air pressure of pressure tank fitted with pump piston. The experimental results are found to have good linearity of about ± 0.1 % and resolution.
Bracalente, Candelaria; Ibañez, Irene L.; Molinari, Beatriz; Palmieri, Mónica; Kreiner, Andrés; Valda, Alejandro
2013-01-01
Purpose: To evaluate the cell response to DNA double-strand breaks induced by low and high linear energy transfer (LET) radiations when the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an essential protein of the nonhomologous end-joining repair pathway, lacks kinase activity. Methods and Materials: CHO10B2, a Chinese hamster ovary cell line, and its derived radiosensitive mutant cell line, irs-20, lacking DNA-PKcs activity, were evaluated after 0 to 3 Gy of γ-rays, plateau and Bragg peak protons, and lithium beams by clonogenic assay, and as a measurement of double-strand breaks, phosphorylated H2AX (γH2AX) foci number and size were quantified by immunocytofluorescence. Results: Irs-20 exhibited greater radiosensitivity and a higher amount of γH2AX foci than CHO10B2 at 6 hours after irradiation for all types of radiations. Remarkably, CHO10B2 and irs-20 maintained their difference in radiosensitivity after high-LET radiation. Six hours after low-LET radiations, irs-20 did not reach basal levels of γH2AX at high doses, whereas CHO10B2 recovered basal levels for all doses. After high-LET radiation, only CHO10B2 exhibited a reduction in γH2AX foci, but it never reached basal levels. Persistent foci in irs-20 confirmed a repair deficiency. Interestingly, after 30 minutes of high-LET radiation both cell lines exhibited large foci (size >0.9 μm 2 ) related to the damage nature, whereas at 6 hours irs-20 showed a higher amount of large foci than CHO10B2, with a 7-fold increase at 3 Gy, that could also be associated to radiosensitivity. Conclusions: We demonstrated, for the first time, an association between deficient DNA-PKcs activity and not only high levels of H2AX phosphorylation but also persistence and size increase of γH2AX foci after high-LET irradiation
Bracalente, Candelaria; Ibañez, Irene L. [Departamento de Micro y Nanotecnología, Comisión Nacional de Energía Atómica, San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires (Argentina); Molinari, Beatriz [Departamento de Radiobiología, Comisión Nacional de Energía Atómica, San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires (Argentina); Palmieri, Mónica [Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Kreiner, Andrés [Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires (Argentina); Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires (Argentina); Valda, Alejandro [Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires (Argentina); and others
2013-11-15
Purpose: To evaluate the cell response to DNA double-strand breaks induced by low and high linear energy transfer (LET) radiations when the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an essential protein of the nonhomologous end-joining repair pathway, lacks kinase activity. Methods and Materials: CHO10B2, a Chinese hamster ovary cell line, and its derived radiosensitive mutant cell line, irs-20, lacking DNA-PKcs activity, were evaluated after 0 to 3 Gy of γ-rays, plateau and Bragg peak protons, and lithium beams by clonogenic assay, and as a measurement of double-strand breaks, phosphorylated H2AX (γH2AX) foci number and size were quantified by immunocytofluorescence. Results: Irs-20 exhibited greater radiosensitivity and a higher amount of γH2AX foci than CHO10B2 at 6 hours after irradiation for all types of radiations. Remarkably, CHO10B2 and irs-20 maintained their difference in radiosensitivity after high-LET radiation. Six hours after low-LET radiations, irs-20 did not reach basal levels of γH2AX at high doses, whereas CHO10B2 recovered basal levels for all doses. After high-LET radiation, only CHO10B2 exhibited a reduction in γH2AX foci, but it never reached basal levels. Persistent foci in irs-20 confirmed a repair deficiency. Interestingly, after 30 minutes of high-LET radiation both cell lines exhibited large foci (size >0.9 μm{sup 2}) related to the damage nature, whereas at 6 hours irs-20 showed a higher amount of large foci than CHO10B2, with a 7-fold increase at 3 Gy, that could also be associated to radiosensitivity. Conclusions: We demonstrated, for the first time, an association between deficient DNA-PKcs activity and not only high levels of H2AX phosphorylation but also persistence and size increase of γH2AX foci after high-LET irradiation.
Design of shielded voltage divider for impulse voltage measurement
Kato, Shohei; Kouno, Teruya; Maruyama, Yoshio; Kikuchi, Koji.
1976-01-01
The dividers used for the study of the insulation and electric discharge phenomena in high voltage equipments have the problems of the change of response characteristics owing to adjacent bodies and of induced noise. To improve the characteristics, the enclosed type divider shielded with metal has been investigated, and the divider of excellent response has been obtained by adopting the frequency-separating divider system, which is divided into two parts, resistance divider (lower frequency region) and capacitance divider (higher frequency region), for avoiding to degrade the response. Theoretical analysis was carried out in the cases that residual inductance can be neglected or can not be neglected in the small capacitance divider, and that the connecting wires are added. Next, the structure of the divider and the design of the electric field for the divider manufactured on the basis of the theory are described. The response characteristics were measured. The results show that 1 MV impulse voltage can be measured within the response time of 10 ns. Though this divider aims at the impulse voltage, the duration time of which is about that of standard lightning impulse, in view of the heat capacity because of the input resistance of 10.5 kΩ, it is expected that the divider can be applied to the voltage of longer duration time by increasing the input resistance in future. (Wakatsuki, Y.)
Experimental research for vacuum gap breakdown in high voltage multi-pulse
Huang Ziping; He Jialong; Chen Sifu; Deng Jianjun; Wang Liping
2008-01-01
Base on the breakdown theory of vacuum gaps, experiments have been done to find out the breakdown electric field intensities in high voltage single-and triple-pulse for 26 vacuum gaps with different shapes. The experimental results match up to the theory and confirm the effect of the pulse-number increase on the breakdown electric field intensity. The key point to decide the macroscopical breakdown electric field intensity of a vacuum gap has been pointed out with some advises about the design of a multi-pulse linear inductive accelerator's accelerate gap. (authors)
Hachay, O. A.; Khachay, O. Y.; Klimko, V. K.; Shipeev, O. V.
2012-04-01
Geological medium is an open dynamical system, which is influenced on different scales by natural and man-made impacts, which change the medium state and lead as a result to a complicated many ranked hierarchic evolution. That is the subject of geo synergetics. Paradigm of physical mesomechanics, which was advanced by academician Panin V.E. and his scientific school, which includes the synergetic approach is a constructive method for research and changing the state of heterogenic materials [1]. That result had been obtained on specimens of different materials. In our results of research of no stationary geological medium in a frame of natural experiments in real rock massifs, which are under high man-made influence it was shown, that the state dynamics can be revealed with use synergetics in hierarchic medium. Active and passive geophysical monitoring plays a very important role for research of the state of dynamical geological systems. It can be achieved by use electromagnetic and seismic fields. Our experience of that research showed the changing of the system state reveals on the space scales and times in the parameters, which are linked with the peculiarities of the medium of the second or higher ranks [2-5]. Results of seismological and electromagnetic information showed the mutual additional information on different space-time levels of rock massive state, which are energetic influenced by explosions, used in mining technology. It is revealed a change of nonlinearity degree in time of the massive state by active influence on it. The description of massive movement in a frame of linear dynamical system does not satisfy the practical situation. The received results are of great significance because for the first time we could find the coincidences with the mathematical theory of open systems and experimental natural results with very complicated structure. On that base we developed a new processing method for the seismological information which can be used in
Hayes, Brett K; Heit, Evan; Swendsen, Haruka
2010-03-01
Inductive reasoning entails using existing knowledge or observations to make predictions about novel cases. We review recent findings in research on category-based induction as well as theoretical models of these results, including similarity-based models, connectionist networks, an account based on relevance theory, Bayesian models, and other mathematical models. A number of touchstone empirical phenomena that involve taxonomic similarity are described. We also examine phenomena involving more complex background knowledge about premises and conclusions of inductive arguments and the properties referenced. Earlier models are shown to give a good account of similarity-based phenomena but not knowledge-based phenomena. Recent models that aim to account for both similarity-based and knowledge-based phenomena are reviewed and evaluated. Among the most important new directions in induction research are a focus on induction with uncertain premise categories, the modeling of the relationship between inductive and deductive reasoning, and examination of the neural substrates of induction. A common theme in both the well-established and emerging lines of induction research is the need to develop well-articulated and empirically testable formal models of induction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.
Experimental demonstration of the KEK induction synchrotron
Takayama, Ken; Torikai, Kota; Shimosaki, Yoshito; Kono, Tadaaki; Iwashita, Taiki; Arakida, Yoshio; Nakamura, Eiji; Shirakata, Masashi; Sueno, Takeshi; Wake, Masayoshi; Otsuka, Kazunori
2007-01-01
Recent progress in the KEK induction synchrotron is presented. In the recent experiment, by using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV Booster ring and captured by the barrier bucket created by the induction step-voltages was accelerated to 6 GeV in the KEK proton synchrotron
An Inexpensive Source of High Voltage
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…
Beijaard, D.; Buitink, J.; Kessels, C.; Peterson, P.; Baker, E.; McGraw, B.
2010-01-01
Teacher induction programs are intended to support the professional development of beginning teachers and thereby contribute to the reduction of teacher attrition during the early teaching years. Teacher induction programs are often based upon a deficit model with a focus on the better organization
Coreless Concept for High Gradient Induction Cell
Krasnykh, Anatoly
2008-01-01
An induction linac cell for a high gradient is discussed. The proposed solid state coreless approach for the induction linac topology (SLIM(reg s ign)) is based on nanosecond mode operation. This mode may have an acceleration gradient comparable with gradients of rf- accelerator structures. The discussed induction system has the high electric efficiency. The key elements are a solid state semiconductor switch and a high electric density dielectric with a thin section length. The energy in the induction system is storied in the magnetic field. The nanosecond current break-up produces the high voltage. The induced voltage is used for acceleration. This manner of an operation allows the use of low voltage elements in the booster part and achieves a high accelerating gradient. The proposed topology was tested in POP (proof of principle) experiments
A New Asymmetrical Current-fed Converter with Voltage Lifting
DELSHAD, M.
2011-05-01
Full Text Available This paper presents a new zero voltage switching current-fed DC-DC converter with high voltage gain. In this converter all switches (main and auxiliary turn on under zero voltage switching and turn off under almost zero voltage switching due to snubber capacitor. Furthermore, the voltage spike across the main switch due to leakage inductance of forward transformer is absorbed. The flyback transformer which is connected to the output in series causes to high voltage gain and less voltage stress on the power devices. Considering high efficiency and voltage gain of this converter, it is suitable for green generated systems such as fuel cells or photovoltaic systems. The presented experimental results verify the integrity of the proposed converter.
Induction technology optimization code
Caporaso, G.J.; Brooks, A.L.; Kirbie, H.C.
1992-01-01
A code has been developed to evaluate relative costs of induction accelerator driver systems for relativistic klystrons. The code incorporates beam generation, transport and pulsed power system constraints to provide an integrated design tool. The code generates an injector/accelerator combination which satisfies the top level requirements and all system constraints once a small number of design choices have been specified (rise time of the injector voltage and aspect ratio of the ferrite induction cores, for example). The code calculates dimensions of accelerator mechanical assemblies and values of all electrical components. Cost factors for machined parts, raw materials and components are applied to yield a total system cost. These costs are then plotted as a function of the two design choices to enable selection of an optimum design based on various criteria. (Author) 11 refs., 3 figs
The influence of motor re-acceleration on voltage sags
Bollen, M.H.J.
1995-01-01
The assumption that a voltage sag is rectangular is not correct in a power system with large induction motor loads. The motors decelerate during the short circuit. After fault-clearing, they will accelerate again, drawing a high reactive current from the supply, causing a prolonged postfault voltage
The LMF triaxial MITL voltage adder system
Mazarakis, M.G.; Smith, D.L.; Bennett, L.F.; Lockner, T.R.; Olson, R.E.; Poukey, J.W.
1992-01-01
The light-ion microfusion driver design consists of multiple accelerating modules fired in coincidence and sequentially in order to provide the desired ion energy, power pulse shape and energy deposition uniformity on an Inertial Confinement Fusion (ICF) target. The basic energy source is a number of Marx generators which, through the appropriate pulse power conditioning, provide the necessary voltage pulse wave form to the accelerating gaps or feeds of each module. The cavity gaps are inductively isolated, and the voltage addition occurs in the center conductor of the voltage adder which is the positive electrode while the electrons of the sheath flow closer to the outer cylinder which is the magnetically insulated cathode electrode. Each module powers a separate two-stage extraction diode which provides a low divergence ion beam. In order to provide the two separate voltage pulses required by the diode, a triaxial adder system is designed for each module. The voltage addition occurs in two separate MITLs. The center hollow cylinder (anode) of the second MITL also serves as the outer cathode electrode for the extension of the first voltage adder MITL. The voltage of the second stage is about twice that of the first stage. The cavities are connected in series to form the outer cylinder of each module. The accelerating modules are positioned radially in a symmetrical way around the fusion chamber. A preliminary conceptual design of the LMF modules with emphasis on the voltage adders and extension MITLs will be presented and discussed
RADLAC II/SMILE performance with a magnetically insulated voltage adder
Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Crist, C.E.; Poukey, J.W.; Prestwich, K.R.; Turman, B.N.; Struve, K.; Welch, D.
1991-01-01
A 12.5-m long Self Magnetically Insulate Transmission LinE (SMILE) that sums the voltages of 8, 2 -MV pulse forming lines was installed in the RADLAC-II linear induction accelerator. The magnetic insulation criteria was calculated using parapotential flow theory and found to agree with MAGIC simulations. High quality annular beams with β perpendicular ≤ 0.1 and a radius r b < 2 cm were measured for currents of 50-100-kA extracted from a magnetic immersed foilless diode. These parameters were achieved with 11 to 15-MV accelerating voltages and 6 to 16-kG diode magnetic field. The experimental results exceeded the design expectations and are in good agreement with code simulations
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
Performance improvement of a slip energy recovery drive system by a voltage-controlled technique
Tunyasrirut, Satean [Department of Instrumentation Engineering, Faculty of Engineering, Pathumwan Institute of Technology, 833 Rama1 Road, Pathumwan, Bangkok 10330 (Thailand); Kinnares, Vijit [Department of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Ngamwiwit, Jongkol [Department of Control Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand)
2010-10-15
This paper introduces the performance improvement of a slip energy recovery drive system for the speed control of a wound rotor induction motor by a voltage-controlled technique. The slip energy occurred in the rotor circuit is transferred back to ac mains supply through a reactor instead of a step up transformer. The objective of the voltage-controlled technique is to increase power factor of the system and to reduce low order harmonics of the input line current. The drive system is designed and implemented using a voltage source inverter in conjunction with a boost chopper for DC link voltage, instead of a conventional drive using a 6 pulse converter or a Scherbius system. The slip power is recovered by the help of a voltage source inverter (VSI) based on a space vector pulse width modulation (SVPWM) technique. In order to keep the speed of the wound rotor induction motor constant over a certain range of operating conditions, the servo state feedback controller designed by a linear quadratic regulator (LQR) is also introduced in this paper. The overall control system is implemented on DSP, DS1104'TMS320F240 controller board. The performance improvement of the proposed system is tested in comparison with the conventional Scherbius system and the modified conventional Scherbius system by a 12 pulse converter in conjunction with a chopper at steady state and at dynamic conditions. A 220 W wound motor is employed for testing. It is found that the motor speed can be controlled to be constant in the operating range of 450-1200 rpm at no load and full load. It is also found that the efficiency of the proposed system is remarkably increased since the harmonics of the input ac line current is reduced while the ac line input power factor is increased. (author)
The dynamic response of a linear brushless D.C. motor
Moghani, J.S.; Eastham, J.F. [Univ. of Bath (United Kingdom). School of Electrical and Electronic Engineering
1995-12-31
The paper describes the use of the Matlab Analogue Simulation Toolbox SIMULINK for the closed loop dynamic modeling of a linear brushless dc motor which is supplied from a delta-modulated inverter. The work is validated by experimental results taken from a large test rig. Linear version of all rotating machines are possible; a rotating machine can be notionally cut along a radial plane and unrolled to yield a linear version. The most popular form of linear machine, as judged by the quantities that have been produced is the linear induction motor. This has the advantage of first an inexpensive secondary that is often a simple iron backed conducting plate, and secondly the possibility of simple voltage control. The linear brushless synchronous motor is potentially more expensive to produce than its induction counterpart because of the permanent magnets which provide the excitation mmf and the necessity of an inverter supply. However the machine has a power factor efficiency product which can be double that of an induction motor together with about twice the tractive force per pole area.
A Method for Solving the Voltage and Torque Equations of the Split ...
Akorede
v′ Voltage applied across the d – axis rotor winding referred ... The embedded MATLAB function and other useful blocks from the ... III. EQUATIONS OF THE SPLIT PHASE INDUCTION MOTOR. The voltage, flux and electromagnetic torque equations are ..... of single phase induction motor using frequency control method ...
Resistors Improve Ramp Linearity
Kleinberg, L. L.
1982-01-01
Simple modification to bootstrap ramp generator gives more linear output over longer sweep times. New circuit adds just two resistors, one of which is adjustable. Modification cancels nonlinearities due to variations in load on charging capacitor and due to changes in charging current as the voltage across capacitor increases.
Sprogøe, Jonas; Rohde, Nicolas
2009-01-01
We claim that induction potentially triggers both individual and organizational learning and by drawing on practice-based theory we discuss how the interplay between individual and organization, what we call a generative dance, ignites both kinds of learning.......We claim that induction potentially triggers both individual and organizational learning and by drawing on practice-based theory we discuss how the interplay between individual and organization, what we call a generative dance, ignites both kinds of learning....
Voltage regulator for generator
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.
Automatic voltage imbalance detector
Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.
1984-01-01
A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.
High voltage investigations for ITER coils
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)
Voltage-pulse generator for electron gun
Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.
1987-01-01
A voltage-pulse generator with combined capacitive and inductive storage devices of an electron gun is described. The current interrupter is a hydrogen thyratron (TGI1-100/8, TGI1-500/16, or TGI1-1000/25) installed in a short magnetic lens. The current interruption time of the thyratrons is 100-300 nsec. When the capacitive storage device is charged to 1 kV, a voltage pulse with an amplitude of 25 kV is obtained at the load
Proton induction linacs as high-intensity neutron sources
Keefe, D.; Hoyer, E.
1981-01-01
Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)
S. El Moursi, Mohamed; Bak-Jensen, Birgitte; Abdel-Rahman, Mansour Hassan
2011-01-01
and optimal tracking secondary voltage control for wind parks based on self-excited induction generators which comprise STATCOM and under-load tap changer (ULTC) substation transformers. The voltage controllers for the STATCOM and ULTC transformer are coordinated and ensure the voltage support. In steady...
High-voltage pulse generator for electron gun power supply
Korenev, S.A.; Enchevich, I.B.; Mikhov, M.K.
1987-01-01
High-voltage pulse generator with combined capacitive and inductive energy storages for electron gun power supply is described. Hydrogen thyratron set in a short magnetic lense is a current breaker. Times of current interruption in thyratrons are in the range from 100 to 300 ns. With 1 kV charging voltage of capacitive energy storage 25 kV voltage pulse is obtained in the load. The given high-voltage pulse generator was used for supply of an electron gun generating 10-30 keV low-energy electron beam
Scaling of induction-cell transverse impedance: effect on accelerator design
Ekdahl, Carl August
2016-01-01
The strength of the dangerous beam breakup (BBU) instability in linear induction accelerators (LIAs) is characterized by the transverse coupling impedance Z ? . This note addresses the dimensional scaling of Z ? , which is important when comparing new LIA designs to existing accelerators with known i BBU growth. Moreover, it is shown that the scaling of Z ? with the accelerating gap size relates BBU growth directly to high-voltage engineering considerations. It is proposed to firmly establish this scaling though a series of AMOS calculations.
Rohde, Nicolas; Sprogøe, Jonas
2007-01-01
that induction potentially triggers both individual and organizational learning and by drawing on practice-based theory we discuss how the interplay between individual and the organization, what we call agenerative dance, ignites both kinds of learning. We focus on and describe the interplay , ignites both kinds...
Plasma internal inductance dynamics in a tokamak
Romero, J.A.
2010-01-01
A lumped parameter model for tokamak plasma current and inductance time evolution as a function of plasma resistance, non-inductive current drive sources and boundary voltage or poloidal field coil current drive is presented. The model includes a novel formulation leading to exact equations for internal inductance and plasma current dynamics. Having in mind its application in a tokamak inductive control system, the model is expressed in state space form, the preferred choice for the design of control systems using modern control systems theory. The choice of system states allows many interesting physical quantities such as plasma current, inductance, magnetic energy, and resistive and inductive fluxes be made available as output equations. The model is derived from energy conservation theorem, and flux balance theorems, together with a first order approximation for flux diffusion dynamics. The validity of this approximation has been checked using experimental data from JET showing an excellent agreement.
Induction accelerators for the phase rotator system
Reginato, Lou; Yu, Simon; Vanecek, Dave
2001-01-01
The principle of magnetic induction has been applied to the acceleration of high current beams in betatrons and a variety of induction accelerators. The linear induction accelerator (LIA) consists of a simple nonresonant structure where the drive voltage is applied to an axially symmetric gap that encloses a toroidal ferromagnetic material. The change in flux in the magnetic core induces an axial electric field that provides particle acceleration. This simple nonresonant (low Q) structure acts as a single turn transformer that can accelerate from hundreds of amperes to tens of kiloamperes, basically only limited by the drive impedance. The LIA is typically a low gradient structure that can provide acceleration fields of varying shapes and time durations from tens of nanoseconds to several microseconds. The efficiency of the LIA depends on the beam current and can exceed 50% if the beam current exceeds the magnetization current required by the ferromagnetic material. The acceleration voltage available is simply given by the expression V=A dB/dt. Hence, for a given cross section of material, the beam pulse duration influences the energy gain. Furthermore, a premium is put on minimizing the diameter, which impacts the total weight or cost of the magnetic material. The diameter doubly impacts the cost of the LIA since the power (cost) to drive the cores is proportional to the volume as well. The waveform requirements during the beam pulse makes it necessary to make provisions in the pulsing system to maintain the desired dB/dt during the useful part of the acceleration cycle. This is typically done two ways, by using the final stage of the pulse forming network (PFN) and by the pulse compensation network usually in close proximity of the acceleration cell. The choice of magnetic materials will be made by testing various materials both ferromagnetic and ferrimagnetic. These materials will include the nickel-iron, silicon steel amorphous and various types of ferrites not
Resistorless Electronically Tunable Grounded Inductance Simulator Design
Herencsár, Norbert; Kartci, Aslihan
2017-01-01
A new realization of grounded lossless positive inductance simulator (PIS) using simple inverting voltage buffer and unity-gain current follower/inverter (CF±) is reported. Considering the input intrinsic resistance of CF± as useful active parameter, the proposed PIS can be considered as resistorless circuit and it only employs in total 16 Metal-Oxide-Semiconductor (MOS) transistors and a grounded capacitor. The resulting equivalent inductance value of the proposed simulator can be adjusted v...
Technological Aspects: High Voltage
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)
Technological Aspects: High Voltage
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.
Coil geometry models for power loss analysis and hybrid inductive ...
CHANDRASEKHARAN NATARAJ
2018-04-26
Apr 26, 2018 ... most of the WPT systems, but often suffers from power loss in the near field area of inductively coupled ... applications in the area of Distribution Generation (DG) ... embedded sensors, and buried devices, work at low voltage.
Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies
2008-04-09
This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.
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
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
Henningsen, Poul
, or if the hottest area is located outside the joint interface, a number of defects may appear: the braze metal may flow away from the joint, the flux may burn off, poor binding of the braze metal may appear or the braze metal may be overheated. Joint geometry as well as electro-magnetic properties of the work piece...... presents a combined numerical and experimental method for determination of appropriate/optimiged coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and copper....... The method has proven to give successful results in brazing tube-plate joints of copper-brass, copper-stainless steel, stainless steel-brass, and stainless steel-stainless steel. A new design of an adjustable flux concentrator for induction heating tube-to-plate joints is proposed and tested on a variety...
High current, 0.5-MA, fast, 100-ns, linear transformer driver experiments
Michael G. Mazarakis
2009-05-01
Full Text Available The linear transformer driver (LTD is a new method for constructing high current, high-voltage pulsed accelerators. The salient feature of the approach is switching and inductively adding the pulses at low voltage straight out of the capacitors through low inductance transfer and soft iron core isolation. Sandia National Laboratories are actively pursuing the development of a new class of accelerator based on the LTD technology. Presently, the high current LTD experimental research is concentrated on two aspects: first, to study the repetition rate capabilities, reliability, reproducibility of the output pulses, switch prefires, jitter, electrical power and energy efficiency, and lifetime measurements of the cavity active components; second, to study how a multicavity linear array performs in a voltage adder configuration relative to current transmission, energy and power addition, and wall plug to output pulse electrical efficiency. Here we report the repetition rate and lifetime studies performed in the Sandia High Current LTD Laboratory. We first utilized the prototype ∼0.4-MA, LTD I cavity which could be reliably operated up to ±90-kV capacitor charging. Later we obtained an improved 0.5-MA, LTD II version that can be operated at ±100 kV maximum charging voltage. The experimental results presented here were obtained with both cavities and pertain to evaluating the maximum achievable repetition rate and LTD cavity performance. The voltage adder experiments with a series of double sized cavities (1 MA, ±100 kV will be reported in future publications.
Inductive Loops for Sensing Position as Signature Signals
Larbani, Sofiane; Malik, Noreha Abdul; Nordin, Anis Norashikin; Khan, Sheroz; Shobaki, Mohammad
2013-01-01
In this paper, an inductive sensing technique made of a special shaped inductive loop is proposed. The inductive loop has an inner turn fitted within an outer turn, making a total inductance value 100μH. This loop is made to be shown with balanced response using three capacitance values of 0.068μF each when a sinusoidal voltage source of 5V peak-to-peak is applied. The variation of the relative permeability of the inductance of the inductive loop (AL) results in a variation of the overall inductance value (L+AL), that causes the output signal to change in term of shape and amplitude for variation of total inductance sweep over a given period of time. As a result of change in inductance value (lμH) there is a correspondence increase of 300mV. Theoretical derivations have showed in close agreement with the simulation plots obtained using Multisim software
Inductive Loops for Sensing Position as Signature Signals
Larbani, Sofiane; Malik, Noreha Abdul; Norashikin Nordin, Anis; Khan, Sheroz; Shobaki, Mohammad
2013-12-01
In this paper, an inductive sensing technique made of a special shaped inductive loop is proposed. The inductive loop has an inner turn fitted within an outer turn, making a total inductance value 100μH. This loop is made to be shown with balanced response using three capacitance values of 0.068μF each when a sinusoidal voltage source of 5V peak-to-peak is applied. The variation of the relative permeability of the inductance of the inductive loop (AL) results in a variation of the overall inductance value (L+AL), that causes the output signal to change in term of shape and amplitude for variation of total inductance sweep over a given period of time. As a result of change in inductance value (lμH) there is a correspondence increase of 300mV. Theoretical derivations have showed in close agreement with the simulation plots obtained using Multisim software.
Analysis of Voltage Forming Methods for Multiphase Inverters
Tadas Lipinskis
2013-05-01
Full Text Available The article discusses advantages of the multiphase AC induction motor over three or less phase motors. It presents possible stator winding configurations for a multiphase induction motor. Various fault control strategies were reviewed for phases feeding the motor. The authors propose a method for quality evaluation of voltage forming algorithm in the inverter. Simulation of a six-phase voltage source inverter, voltage in which is formed using a simple SPWM control algorithm, was performed in Matlab Simulink. Simulation results were evaluated using the proposed method. Inverter’s power stage was powered by 400 V DC source. The spectrum of output currents was analysed and the magnitude of the main frequency component was at least 12 times greater than the next biggest-magnitude component. The value of rectified inverter voltage was 373 V.Article in Lithuanian
Instantaneous Switching Processes in Quasi-Linear Circuits
Rositsa Angelova
2004-01-01
Full Text Available The paper considers instantaneous processes in electrical circuits produced by the stepwise change of the capacitance of the capacitor and the inductance of the inductor and by the switching on and switching off of the circuit. In order to determine the set of electrical circuits, for which it is possible to explicitly obtain the values of the currents and the voltages at the end of the instantaneous process, a classification of the networks with nonlinear elements is introduced in the paper. The instantaneous switching process in the moment t0 is approximated when T->t0 with a sequence of processes in the interval [t0, T]. For quasi-linear inductive and capacitive circuits; we present the type of the system satisfied by the currents and the voltages, the charges, as well as the fluxes in the interval [t0, T]. From this system, after passage to the limit T->t0, we obtain the formulas for the values of the circuits at the end of the instantaneous process. The obtained results are applied for the analysis of particular processes.
Cuneo, M.E.; Hanson, D.L.; Menge, P.R.; Poukey, J.W.; Savage, M.E.
1994-01-01
SABRE (Sandia Accelerator and Beam Research Experiment) is a ten-cavity linear induction magnetically insulated voltage adder (6 MV, 300 kA) operated in positive polarity to investigate issues relevant to ion beam production and propagation for inertial confinement fusion. The voltage adder section is coupled to an applied-B extraction ion diode via a long coaxial output transmission line. Observations indicate that the power propagates in a vacuum wave prior to electron emission. After the electron emission threshold is reached, power propagates in a magnetically insulated wave. The precursor is observed to have a dominant impact on he turn-on, impedance history, and beam characteristics of applied-B ion diodes since the precursor voltage is large enough to cause electron emission at the diode from both the cathode feed and cathode tips. The amplitude of the precursor at the load (3--4.5 MV) is a significant fraction of the maximum load voltage (5--6 MV) because (1) the transmission line gaps ( ∼ 9 cm at output) and therefore impedances are relatively large, and hence the electric field threshold for electron emission (200 to 300 kV/cm) is not reached until well into the power pulse rise time; and (2) the rapidly falling forward wave and diode impedance reduces the ratio of main pulse voltage to precursor voltage. Experimental voltage and current data from the transmission line and the ion diode will be presented and compared with TWOQUICK (2-D electromagnetic PIC code) simulations and analytic models
Axial electric wake field inside the induction gap exited by the intense electron beam
Zhang Kaizhi; Zhang Huang; Long Jidong; Yang Guojun; He Xiaozhong; Wang Huacen
2008-01-01
While an intense electron beam passes through the accelerating gaps of a linear induction accelerator, a strong wake field will be excited. In this paper a relatively simple model is established based on the interaction between the transverse magnetic wake field and the electron beam, and the numerical calculation in succession generates a magnetic wake field distribution along the accelerator and along the beam pulse as well. The axial electric wake field is derived based on the relation between field components of a resonant mode. According to some principles in existence, the influence of this field on the high voltage properties of the induction gap is analyzed. The Dragon-I accelerator is taken as an example, and its maximum electric wake field is about 17 kV/cm, which means the effect of the wake field is noticeable. (authors)
The Prototype Inductive Adder With Droop Compensation for the CLIC Kicker Systems
Holma, J
2014-01-01
The Compact Linear Collider (CLIC) study is exploring the scheme for an electron-positron collider with high luminosity and a nominal center-of-mass energy of 3 TeV. The CLIC predamping rings and damping rings (DRs) will produce, through synchrotron radiation, an ultralow emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the extraction kickers of the DRs are particularly demanding: the flattops of the pulses must be ±12.5 kV with a combined ripple and droop of not more than ±0.02% (±2.5 V). An inductive adder is a very promising approach to meeting the specifications. Recently, a five-layer prototype has been built at CERN. Passive analog modulation has been applied to compensate the voltage droop, for example of the pulse capacitors. The output waveforms of the prototype inductive adder have been compared with predictions of the voltage droop and pulse shape. Conclusions are drawn concern...
Control and Testing of a Dynamic Voltage Restorer (DVR) at Medium Voltage Level
Nielsen, John Godsk; Newman, Michael; Nielsen, Hans Ove
2004-01-01
power sensitive loads from voltage sags. This paper reports practical test results obtained on a medium voltage (10 kV) level using a DVR at a Distribution test facility in Kyndby, Denmark. The DVR was designed to protect a 400-kVA load from a 0.5-p.u. maximum voltage sag. The reported DVR verifies......The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage sags. Implementations of the DVR have been proposed at both a low voltage (LV) level, as well as a medium voltage (MV) level; and give an opportunity to protect high...... the use of a feed-forward and feed-back technique of the controller and it obtains both good transient and steady state responses. The effect of the DVR on the system is experimentally investigated under both faulted and non-faulted system states, for a variety of linear and non-linear loads. Variable...
Wang, Z.; Lu, K.; Ye, Y.
2011-01-01
According to saliency of permanent magnet synchronous motor (PMSM), the information of rotor position is implied in performance of stator inductances due to the magnetic saturation effect. Researches focused on the initial rotor position estimation of PMSM by injecting modulated pulse voltage...... vectors. The relationship between the inductance variations and voltage vector positions was studied. The inductance variation effect on estimation accuracy was studied as well. An improved five-pulses injection method was proposed, to improve the estimation accuracy by choosing optimaized voltage vectors...
Power angle control of grid-connected voltage source converter in a wind energy application
Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering
1996-12-31
In this thesis, the connection of a voltage source converter to the grid in a wind energy application is examined. The possibility of using a cheap control system without grid current measurements, is investigated. The control method is based on controlling the voltage angle of the inverter, which governs the active power flow. The highest frequency of the power variation, coming from wind turbine, is approx. 5 Hz. Since the proposed control method easily can handle such power variations it is very well suited for wind turbine applications. The characteristics of the system depend on the DC-link capacitor, the grid filter inductance and resistance. Large values of the resistance damp the system well but increase the energy losses. A high inductance leads to a reduced harmonic level on the grid but makes the system slower. By using feed-forward of the generator/rectifier current signal, the performance is increased compared to an ordinary PI-control. Combining the Linear Quadratic (LQ) control method with Kalman filtered input signals, a robust control method with a good performance is obtained. The LQ controller controls both the phase displacement angle and the modulation index, resulting in higher bandwidth, and the typical power angle resonance at the grid frequency disappears. 22 refs, 109 figs, 14 tabs
Inductive Non-Contact Position Sensor
Youngquist, Robert; Garcia, Alyssa; Simmons, Stephen
2010-01-01
Optical hardware has been developed to measure the depth of defects in the Space Shuttle Orbiter's windows. In this hardware, a mirror is translated such that its position corresponds to the defect's depth, so the depth measurement problem is transferred to a mirror-position measurement problem. This is preferable because the mirror is internal to the optical system and thus accessible. Based on requirements supplied by the window inspectors, the depth of the defects needs to be measured over a range of 200 microns with a resolution of about 100 nm and an accuracy of about 400 nm. These same requirements then apply to measuring the position of the mirror, and in addition, since this is a scanning system, a response time of about 10 ms is needed. A market search was conducted and no sensor that met these requirements that also fit into the available housing volume (less than one cubic inch) was found, so a novel sensor configuration was constructed to meet the requirements. This new sensor generates a nearly linearly varying magnetic field over a small region of space, which can easily be sampled, resulting in a voltage proportional to position. Experiments were done with a range of inductor values, drive voltages, drive frequencies, and inductor shapes. A rough mathematical model was developed for the device that, in most aspects, describes how it operates and what electrical parameters should be chosen for best performance. The final configuration met all the requirements, yielding a small rugged sensor that was easy to use and had nanometer resolution over more than the 200-micron range required. The inductive position sensor is a compact device (potentially as small as 2 cubic centimeters), which offers nanometer-position resolution over a demonstrated range of nearly 1 mm. One of its advantages is the simplicity of its electrical design. Also, the sensor resolution is nearly uniform across its operational range, which is in contrast to eddy current and
Characteristics of output voltage and current of integrated nanogenerators
Yang, Rusen; Qin, Yong; Li, Cheng; Dai, Liming; Wang, Zhong Lin
2009-01-01
three criteria: Schottky behavior test, switching-polarity tests, and linear superposition of current and voltage tests. The 11 tests can effectively rule out the system artifacts, whose sign does not change with the switching measurement polarity
Sander, K F
1964-01-01
Linear Network Theory covers the significant algebraic aspect of network theory, with minimal reference to practical circuits. The book begins the presentation of network analysis with the exposition of networks containing resistances only, and follows it up with a discussion of networks involving inductance and capacity by way of the differential equations. Classification and description of certain networks, equivalent networks, filter circuits, and network functions are also covered. Electrical engineers, technicians, electronics engineers, electricians, and students learning the intricacies
Reverse engineering of inductive fault current limiters
Pina, J M; Neves, M Ventim; Rodrigues, A L [Centre of Technology and Systems Faculdade de Ciencias e Tecnologia, Nova University of Lisbon Monte de Caparica, 2829-516 Caparica (Portugal); Suarez, P; Alvarez, A, E-mail: jmmp@fct.unl.p [' Benito Mahedero' Group of Electrical Applications of Superconductors Escuela de IngenierIas Industrials, University of Extremadura Avenida de Elvas s/n, 06006 Badajoz (Spain)
2010-06-01
The inductive fault current limiter is less compact and harder to scale to high voltage networks than the resistive one. Nevertheless, its simple construction and mechanical robustness make it attractive in low voltage grids. Thus, it might be an enabling technology for the advent of microgrids, low voltage networks with dispersed generation, controllable loads and energy storage. A new methodology for reverse engineering of inductive fault current limiters based on the independent analysis of iron cores and HTS cylinders is presented in this paper. Their electromagnetic characteristics are used to predict the devices' hysteresis loops and consequently their dynamic behavior. Previous models based on the separate analysis of the limiters' components were already derived, e.g. in transformer like equivalent models. Nevertheless, the assumptions usually made may limit these models' application, as shown in the paper. The proposed methodology obviates these limitations. Results are validated through simulations.
Reverse engineering of inductive fault current limiters
Pina, J M; Neves, M Ventim; Rodrigues, A L; Suarez, P; Alvarez, A
2010-01-01
The inductive fault current limiter is less compact and harder to scale to high voltage networks than the resistive one. Nevertheless, its simple construction and mechanical robustness make it attractive in low voltage grids. Thus, it might be an enabling technology for the advent of microgrids, low voltage networks with dispersed generation, controllable loads and energy storage. A new methodology for reverse engineering of inductive fault current limiters based on the independent analysis of iron cores and HTS cylinders is presented in this paper. Their electromagnetic characteristics are used to predict the devices' hysteresis loops and consequently their dynamic behavior. Previous models based on the separate analysis of the limiters' components were already derived, e.g. in transformer like equivalent models. Nevertheless, the assumptions usually made may limit these models' application, as shown in the paper. The proposed methodology obviates these limitations. Results are validated through simulations.
Effect of different methods of pulse width modulation on power losses in an induction motor
Gulyaev, Alexander; Fokin, Dmitrii; Shuharev, Sergey; Ten, Evgenii
2017-10-01
We consider the calculation of modulation power losses in a system “induction motor-inverter” for various pulse width modulation (PWM) methods of the supply voltage. Presented values of modulation power losses are the result of modeling a system “DC link - two-level three-phase voltage inverter - induction motor - load”. In this study the power losses in a system “induction motor - inverter” are computed, as well as losses caused by higher harmonics of PWM supply voltage, followed by definition of active power consumed by the DC link for a specified value mechanical power on the induction motor shaft. Mechanical power was determined by the rotation speed and the torque on the motor shaft in various quasi-sinusoidal supply voltage PWM modes. These calculations reveal the best coefficient of performance (COP) in a system of a variable frequency drive (VFD) with independent voltage inverter controlled by induction motor PWM.
Effect of power quality on windings temperature of marine induction motors
Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)], E-mail: piotrg@am.gdynia.pl
2009-10-15
Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system.
Effect of power quality on windings temperature of marine induction motors. Part I: Machine model
Gnacinski, P. [Gdynia Maritime Univ., Dept. of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)
2009-10-15
Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system. (author)
Shilov, Georgi E
1977-01-01
Covers determinants, linear spaces, systems of linear equations, linear functions of a vector argument, coordinate transformations, the canonical form of the matrix of a linear operator, bilinear and quadratic forms, Euclidean spaces, unitary spaces, quadratic forms in Euclidean and unitary spaces, finite-dimensional space. Problems with hints and answers.
1 MV low-induction pulse generator
Koba, G.I.; Koba, Yu.V.; Slivkov, I.N.; Sukhov, A.D.; Tarumov, Eh.Z.
1980-01-01
A high-voltage pulse generator is described. The generator Uses the Arkadiev-Marx circuit at 1 MV voltage and 12 kJ energy; the inductance of the discharge circuit is 1.3 μN. Low inductance of the generator has been obtained due to the use of low-inductance capacitors and employment of bifilar buses with oil barrier insulation. To provide reliable generator triggering, an ignition circuit has been developed with a resistive coupling between generator steps, based on controlled three-electrode sparkgaps with a distorted field. The generator switching time is slightly dependent on pressure and constitutes 200-300 ns. The generator efficiency is 83%
based dynamic voltage restorer
HOD
operation due to presence of increased use of nonlinear loads (computers, microcontrollers ... simulations of a dynamic voltage restorer (DVR) was achieved using MATLAB/Simulink. ..... using Discrete PWM generator, then the IGBT inverter.
High voltage engineering fundamentals
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
A compact, all solid-state LC high voltage generator.
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.
Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.
2013-01-01
For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5–10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%–2% in the submillimeter wavelength region).
Voltage Quench Dynamics of a Kondo System.
Antipov, Andrey E; Dong, Qiaoyuan; Gull, Emanuel
2016-01-22
We examine the dynamics of a correlated quantum dot in the mixed valence regime. We perform numerically exact calculations of the current after a quantum quench from equilibrium by rapidly applying a bias voltage in a wide range of initial temperatures. The current exhibits short equilibration times and saturates upon the decrease of temperature at all times, indicating Kondo behavior both in the transient regime and in the steady state. The time-dependent current saturation temperature connects the equilibrium Kondo temperature to a substantially increased value at voltages outside of the linear response. These signatures are directly observable by experiments in the time domain.
Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities
Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede
2010-01-01
This paper presents new five-level current-source inverters (CSIs) with voltage/current buck–boost capability, unlike existing five-level CSIs where only voltage–boost operation is supported. The proposed inverters attain self-inductive-currentbalancing per switching cycle at their dc front ends...... without having to include additional balancing hardware or complex control manipulation. The inverters can conveniently be controlled by using the well-established phase-shifted carrier modulation scheme with only two additional linear references and a mapping logic table needed. Existing modulators can...
Máthé, Lászlo; Yang, Feng; Wang, Dong
2016-01-01
for the entire drive systems have to be designed. A linearization and simplification to single phase model can be performed; however, when inductance is present at the grid side its performance is not satisfactory. The problem is mainly caused by neglecting the continuous conduction mode of the rectifier......Reducing the DC-link capacitance considerably is a new trend in many applications, such as: motor drives, electrolysers etc.. A straight forward method for modelling the diode front-end is to build a non-linear diode based model. This non-linear model gives difficulties when the controllers...... in the simplified model. This article proposes a simplified linear model where the continuous conduction mode is also considered. The DC-link voltage and current waveforms obtained through the proposed simplified model matches very well the waveforms obtained with the three phase diode based model and also...
M. Hosseini Abardeh
2015-03-01
Full Text Available The matrix converter instability can cause a substantial distortion in the input currents and voltages which leads to the malfunction of the converter. This paper deals with the effects of input filter type, grid inductance, voltage fed to the modulation algorithm and the synchronous rotating digital filter time constant on the stability and performance of the matrix converter. The studies are carried out using eigenvalues of the linearized system and simulations. Two most common schemes for the input filter (LC and RLC are analyzed. It is shown that by a proper choice of voltage input to the modulation algorithm, structure of the input filter and its parameters, the need for the digital filter for ensuring the stability can be resolved. Moreover, a detailed model of the system considering the switching effects is simulated and the results are used to validate the analytical outcomes. The agreement between simulation and analytical results implies that the system performance is not deteriorated by neglecting the nonlinear switching behavior of the converter. Hence, the eigenvalue analysis of the linearized system can be a proper indicator of the system stability.
Optimal condition of memristance enhancement circuit using external voltage source
Hiroya Tanaka
2014-05-01
Full Text Available Memristor provides nonlinear response in the current-voltage characteristic and the memristance is modulated using an external voltage source. We point out by solving nonlinear equations that an optimal condition of the external voltage source exists for maximizing the memristance in such modulation scheme. We introduce a linear function to describe the nonlinear time response and derive an important design guideline; a constant ratio of the frequency to the amplitude of the external voltage source maximizes the memristance. The analysis completely accounts for the memristance behavior.
Inexpensive system protects megawatt resistance-heating furnace against high-voltage surges
Stearns, E. J.
1971-01-01
Coolant gas extinguishes arcing across the break in a heater element. Air-gap shunt which bypasses high voltage impressed across the circuit prevents damage if the resistance elements break and open the inductive circuit.
Device for monitoring cell voltage
Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE
2012-08-21
A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.
Local tuning of the order parameter in superconducting weak links: A zero-inductance nanodevice
Winik, Roni; Holzman, Itamar; Dalla Torre, Emanuele G.; Buks, Eyal; Ivry, Yachin
2018-03-01
Controlling both the amplitude and the phase of the superconducting quantum order parameter (" separators="|ψ ) in nanostructures is important for next-generation information and communication technologies. The lack of electric resistance in superconductors, which may be advantageous for some technologies, hinders convenient voltage-bias tuning and hence limits the tunability of ψ at the microscopic scale. Here, we demonstrate the local tunability of the phase and amplitude of ψ, obtained by patterning with a single lithography step a Nb nano-superconducting quantum interference device (nano-SQUID) that is biased at its nanobridges. We accompany our experimental results by a semi-classical linearized model that is valid for generic nano-SQUIDs with multiple ports and helps simplify the modelling of non-linear couplings among the Josephson junctions. Our design helped us reveal unusual electric characteristics with effective zero inductance, which is promising for nanoscale magnetic sensing and quantum technologies.
Irwin Yousept
2010-07-01
Full Text Available An optimal control problem arising in the context of 3D electromagnetic induction heating is investigated. The state equation is given by a quasilinear stationary heat equation coupled with a semilinear time harmonic eddy current equation. The temperature-dependent electrical conductivity and the presence of pointwise inequality state-constraints represent the main challenge of the paper. In the first part of the paper, the existence and regularity of the state are addressed. The second part of the paper deals with the analysis of the corresponding linearized equation. Some suffcient conditions are presented which guarantee thesolvability of the linearized system. The final part of the paper is concerned with the optimal control. The aim of the optimization is to find the optimal voltage such that a desired temperature can be achieved optimally. The corresponding first-order necessary optimality condition is presented.
Control of DFIG-WT under unbalanced grid voltage conditions
Luna, Alvaro; Lina, Kleber; Corcoles, Felipe
2009-01-01
The voltage oriented control in the synchronous reference frame (VOC-SRF) have been extensively used for controlling wind turbines based on doubly fed induction generators (DFIG-WTs) through the rotor side converter of a back to back power processor. Although its performance is fast and accurate ...
The light ion pulsed power induction accelerator for ETF
Mazarakis, M.G.; Olson, R.E.; Olson, C.L.; Smith, D.L.; Bennett, L.F.
1994-01-01
Our Engineering Test Facility (ETF) driver concept is based on HERMES III and RHEPP technologies. Actually, it is a scaled-down version of the LMF design incorporating repetition rate capabilities of up to 10 Hz CW. The preconceptual design presented here provides 200-TW peak power to the ETF target during 10 ns, equal to 2-MJ total ion beam energy. Linear inductive voltage addition driving a self-magnetically insulated transmission line (MITL) is utilized to generate the 36-MV peak voltage needed for lithium ion beams. The ∼ 3-MA ion current is achieved by utilizing many accelerating modules in parallel. Since the current per module is relatively modest (∼300 kA), two-stage or one-stage extraction diodes can be utilized for the generation of singly charged lithium ions. The accelerating modules are arranged symmetrically around the fusion chamber in order to provide uniform irradiation onto the ETF target. In addition, the modules are fired in a programmed sequence in order to generate the optimum power pulse shape onto the target. This design utilizes RHEPP accelerator modules as the principal power source
Malrait, F.
2001-02-15
In order to improve the efficiency of a speed variator or to make autonomous the control of induction motors without mechanical sensor, the speed variator must integrate with a good precision the parameters of the motor to which it is connected. In this work, an identification phase when the motor is off is proposed. This raises the problem of the modeling of the induction motor and of the power stage (saturation model, voltage drop in the power stage components) in an unusual operation zone for a speed variator. The knowledge of the off-line electrical parameters is thus not sufficient. During normal operation, the thermal drift of resistors leads to a parametric error which can create blocking problems in the low sped domain or which can significantly lower the efficiency. The low-speed zone has been analyzed. This zone contains some intrinsic properties of the induction motor: instability, non-observability (first order). The synthesis of an observer of the induction motor is proposed which is based on the linearization of the system around a trajectory. A construction method has been developed to generate a non-singular observer for a system changing with time and having observability singularities. This result comes from this study on systems having controllability singularities for linear systems with time-variable coefficients. An exogenous loop is explicitly proposed which allows to transform the original system into integrator chains without singularities. (J.S.)
High-voltage nanosecond pulse shaper
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
The supply voltage apparatus of the CUORE experiment
Arnaboldi, C.; Baú, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A. [INFN, Sezione di Milano Bicocca - Istituto Nazionale di Fisica Nucleare, Piazza della Scienza 3 Milano (Italy); Università di Milano Bicocca - Dipartimento di Fisica, Piazza della Scienza 3 Milano (Italy); Pessina, G., E-mail: Pessina@mib.infn.it [INFN, Sezione di Milano Bicocca - Istituto Nazionale di Fisica Nucleare, Piazza della Scienza 3 Milano (Italy); Università di Milano Bicocca - Dipartimento di Fisica, Piazza della Scienza 3 Milano (Italy)
2016-07-11
The Electronics system of experiments for the study of rare decays, such as the neutrino-less double beta decay, must be very stable over very long expected runs. We introduce our solution for the power supply of such an experiment, CUORE. In this case the power supply chain consists of a series of ACDCs, followed by DCDCs and then Linear Regulators. We emphasize here our approach to the DCDC regulation system that was designed with a complete rejection of the switching noise, across 100 MHz bandwidth. In the experimental layout the DCDC will be located far from the very front-end, with long connecting cables (10 m). We introduced our very simple and safe solution to prevent huge over-voltages, due to the energy stored in the inductance of the cables, generated after the release of accidental short circuits, so avoiding destructive effects. Some micro-controllers are present on every board and take care of the DCDC operation. These micro-controllers are managed from the control room, via CAN BUS protocol coupled via optical fibres. CUORE is an array of 1000 cryogenic detectors that will need 30 of our DCDCs.
The supply voltage apparatus of the CUORE experiment
Arnaboldi, C.; Baú, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.
2016-07-01
The Electronics system of experiments for the study of rare decays, such as the neutrino-less double beta decay, must be very stable over very long expected runs. We introduce our solution for the power supply of such an experiment, CUORE. In this case the power supply chain consists of a series of ACDCs, followed by DCDCs and then Linear Regulators. We emphasize here our approach to the DCDC regulation system that was designed with a complete rejection of the switching noise, across 100 MHz bandwidth. In the experimental layout the DCDC will be located far from the very front-end, with long connecting cables (10 m). We introduced our very simple and safe solution to prevent huge over-voltages, due to the energy stored in the inductance of the cables, generated after the release of accidental short circuits, so avoiding destructive effects. Some micro-controllers are present on every board and take care of the DCDC operation. These micro-controllers are managed from the control room, via CAN BUS protocol coupled via optical fibres. CUORE is an array of 1000 cryogenic detectors that will need 30 of our DCDCs.
The supply voltage apparatus of the CUORE experiment
Arnaboldi, C.; Baú, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.
2016-01-01
The Electronics system of experiments for the study of rare decays, such as the neutrino-less double beta decay, must be very stable over very long expected runs. We introduce our solution for the power supply of such an experiment, CUORE. In this case the power supply chain consists of a series of ACDCs, followed by DCDCs and then Linear Regulators. We emphasize here our approach to the DCDC regulation system that was designed with a complete rejection of the switching noise, across 100 MHz bandwidth. In the experimental layout the DCDC will be located far from the very front-end, with long connecting cables (10 m). We introduced our very simple and safe solution to prevent huge over-voltages, due to the energy stored in the inductance of the cables, generated after the release of accidental short circuits, so avoiding destructive effects. Some micro-controllers are present on every board and take care of the DCDC operation. These micro-controllers are managed from the control room, via CAN BUS protocol coupled via optical fibres. CUORE is an array of 1000 cryogenic detectors that will need 30 of our DCDCs.
High frequency breakdown voltage
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
Computer simulation of a 3-phase induction motor
Memon, N.A.; Unsworth, P.J.
2004-01-01
Computer Simulation of a 3-phase squirrel-cage induction motor is presented in Microsoft QBASIC for understanding trends and various operational modes of an induction motor. Thyristor fed, phase controlled induction motor (three-wire) model has been simulated. In which voltage is applied to the motor stator winding through back-to-back connected thyristors as controlled switches in series with the stator. The simulated induction motor system opens up towards a wide range of investigation/analysis options for research and development work in the field. Key features of the simulation performed are highlighted for development of better understanding of the work done. Complete study of an Induction Motor, starting modes in terms the voltage/current, torque/speed characteristics and their graphical representation produced is presented. Ideal agreement of the simulation results with the notional outcome encourages users to go ahead for various hardware development projects based on the study through the simulation. (author)
Analysis on voltage stability of PFN in modulator using De-Qing network
Wang Dong; Zhang Yongming; Zhu Fuquan
1987-01-01
Using the numerical simulation of PFN charging circuit and De-Qing network, a study of voltage stability of BEPC 80 MW klystron pulse modulator has been carried out. The results presented in the paper indicate the quantitative correlation between leakage inductance and voltage stability
An optical fiber Bragg grating and piezoelectric ceramic voltage sensor
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.
An optical fiber Bragg grating and piezoelectric ceramic voltage sensor.
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.
Zhou Zhicheng
1992-01-01
A digital voltage discriminator is described, which is synthesized by digital comparator and ADC. The threshold is program controllable with high stability. Digital region of confusion is approximately equal to 1.5 LSB. This discriminator has a single channel analyzer function model with channel width of 1.5 LSB
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.
Geomagnetism and Induced Voltage
Abdul-Razzaq, W.; Biller, R. D.
2010-01-01
Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it…
Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar
2013-01-01
Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system...... to unbalanced faults. The compensation of unbalanced voltage sags and voltage unbalance in the CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0........ The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbalances, for the tested cases in the CIGRE LV test network are mainly due to single phase loads and due...
Suwono.
1978-01-01
A linear gate providing a variable gate duration from 0,40μsec to 4μsec was developed. The electronic circuity consists of a linear circuit and an enable circuit. The input signal can be either unipolar or bipolar. If the input signal is bipolar, the negative portion will be filtered. The operation of the linear gate is controlled by the application of a positive enable pulse. (author)
Chang, C.-H.; Leou, K.-C.; Lin Chaung; Lin, T.-L.; Tseng, C.-W.; Tsai, C.-H.
2003-01-01
In this study, we have experimentally demonstrated the real-time closed-loop control of both ion density and ion energy in a chlorine inductively coupled plasma etcher. To measure positive ion density, the trace rare gases-optical emission spectroscopy is used to measure the chlorine positive ion density. An rf voltage probe is adopted to measure the root-mean-square rf voltage on the electrostatic chuck which is linearly dependent on sheath voltage. One actuator is a 13.56 MHz rf generator to drive the inductive coil seated on a ceramic window. The second actuator is also a 13.56 MHz rf generator to power the electrostatic chuck. The closed-loop controller is designed to compensate for process drift, process disturbance, and pilot wafer effect and to minimize steady-state error of plasma parameters. This controller has been used to control the etch process of unpatterned polysilicon. The experimental results showed that the closed-loop control had a better repeatability of plasma parameters compared with open-loop control. The closed-loop control can eliminate the process disturbance resulting from reflected power. In addition, experimental results also demonstrated that closed-loop control has a better reproducibility in etch rate as compared with open-loop control
Vretenar, M
2014-01-01
The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics
Zhang Jian; Huang Yiyun; Liu Baohua; Guo Wenjun; Shen Xiaoling; Wei Wei
2011-01-01
A high voltage power supply system has been developed for the diagnostic neutral beam on the HT-7 experimental Tokamak, and the over-voltage phenomenon of storage capacitor was founded in the experiment. In order to analyse and resolve this problem, the structure and principle of high voltage power supply is described and the primary high voltage charging power supply system is introduced in detail. The phenomenon of over-voltage on the capacitors is also studied with circuit model, and the conclusion is obtained that the leakage inductance is the mA in reason which causes the over-voltage on the capacitors. (authors)
Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network
Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar
2013-01-01
Any problem in voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM), Dynamic Voltage Restorer (DVR) etc. are commonly used for the mitigation of voltage p....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0.......Any problem in voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM), Dynamic Voltage Restorer (DVR) etc. are commonly used for the mitigation of voltage...... problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults...
Linearization Method and Linear Complexity
Tanaka, Hidema
We focus on the relationship between the linearization method and linear complexity and show that the linearization method is another effective technique for calculating linear complexity. We analyze its effectiveness by comparing with the logic circuit method. We compare the relevant conditions and necessary computational cost with those of the Berlekamp-Massey algorithm and the Games-Chan algorithm. The significant property of a linearization method is that it needs no output sequence from a pseudo-random number generator (PRNG) because it calculates linear complexity using the algebraic expression of its algorithm. When a PRNG has n [bit] stages (registers or internal states), the necessary computational cost is smaller than O(2n). On the other hand, the Berlekamp-Massey algorithm needs O(N2) where N(≅2n) denotes period. Since existing methods calculate using the output sequence, an initial value of PRNG influences a resultant value of linear complexity. Therefore, a linear complexity is generally given as an estimate value. On the other hand, a linearization method calculates from an algorithm of PRNG, it can determine the lower bound of linear complexity.
High-output microwave detector using voltage-induced ferromagnetic resonance
Shiota, Yoichi; Suzuki, Yoshishige; Miwa, Shinji; Tamaru, Shingo; Nozaki, Takayuki; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji
2014-01-01
We investigated the voltage-induced ferromagnetic resonance (FMR) with various DC bias voltage and input RF power in magnetic tunnel junctions. We found that the DC bias monotonically increases the homodyne detection voltage due to the nonlinear FMR originating in an asymmetric magnetization-potential in the free layer. In addition, the linear increase of an output voltage to the input RF power in the voltage-induced FMR is more robust than that in spin-torque FMR. These characteristics enable us to obtain an output voltage more than ten times than that of microwave detectors using spin-transfer torque
A compact 100 kV high voltage glycol capacitor.
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.
Responsive demand to mitigate slow recovery voltage sags
Garcia-Valle, Rodrigo; da Silva, Luiz Carlos Pereira; Xu, Zhao
2012-01-01
, and reactive power reserve for peak load management through price responsive methods and also as energy providers through embedded generation technologies. This article introduces a new technology, called demand as voltagecontrolled reserve, which can help mitigation of momentary voltage sags. The technology...... faults. This article presents detailed models, discussion, and simulation tests to demonstrate the technical viability and effectiveness of the demand as voltage-controlled reserve technology for mitigating voltage sags....... can be provided by thermostatically controlled loads as well as other types of load. This technology has proven to be effective in distribution systems with a large composition of induction motors, when voltage sags present slow recovery characteristics because of the deceleration of the motors during...
Carpenter, R.T.; Torven, S.
1986-07-01
The properties of a strong double layer in a current circuit with a capacitance and an inductance are investigated in a triple plasma device. The double layer gives rise to a region of negative differential resistance in the current-voltage characteristic of the device, and this gives non-linear oscillations in the current and the potential drop over the double layer (PhiDL). For a sufficiently large circuit inductance PhiDL reaches an amplitude given by the induced voltage (-LdI/dt) which is much larger than the circuit EMF due to the rapid current decrease when PhiDL increases. A variable potential minimum exists in the plasma on the low potential side of the double layer, and the depth of the minimum increases when PhiDL increases. An increasing fraction of the electrons incident at the double layer are then reflected, and this is found to be the main process giving rise to the negative differential resistance. A qualitative model for the variation of the minimum potential with PhiDL is also proposed. It is based on the condition that the minimum potential must adjust itself self-consistentely so that quasi-neutrality is maintained in the plasma region where the minimum is assumed. (authors)
Said-Houari, Belkacem
2017-01-01
This self-contained, clearly written textbook on linear algebra is easily accessible for students. It begins with the simple linear equation and generalizes several notions from this equation for the system of linear equations and introduces the main ideas using matrices. It then offers a detailed chapter on determinants and introduces the main ideas with detailed proofs. The third chapter introduces the Euclidean spaces using very simple geometric ideas and discusses various major inequalities and identities. These ideas offer a solid basis for understanding general Hilbert spaces in functional analysis. The following two chapters address general vector spaces, including some rigorous proofs to all the main results, and linear transformation: areas that are ignored or are poorly explained in many textbooks. Chapter 6 introduces the idea of matrices using linear transformation, which is easier to understand than the usual theory of matrices approach. The final two chapters are more advanced, introducing t...
Streamer model for high voltage water switches
Sazama, F.J.; Kenyon, V.L. III
1979-01-01
An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented
Coupling and decoupling of the accelerating units for pulsed synchronous linear accelerator
Shen, Yi; Liu, Yi; Ye, Mao; Zhang, Huang; Wang, Wei; Xia, Liansheng; Wang, Zhiwen; Yang, Chao; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun
2017-12-01
A pulsed synchronous linear accelerator (PSLA), based on the solid-state pulse forming line, photoconductive semiconductor switch, and high gradient insulator technologies, is a novel linear accelerator. During the prototype PSLA commissioning, the energy gain of proton beams was found to be much lower than expected. In this paper, the degradation of the energy gain is explained by the circuit and cavity coupling effect of the accelerating units. The coupling effects of accelerating units are studied, and the circuit topologies of these two kinds of coupling effects are presented. Two methods utilizing inductance and membrane isolations, respectively, are proposed to reduce the circuit coupling effects. The effectiveness of the membrane isolation method is also supported by simulations. The decoupling efficiency of the metal drift tube is also researched. We carried out the experiments on circuit decoupling of the multiple accelerating cavity. The result shows that both circuit decoupling methods could increase the normalized voltage.
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.
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.
Design, analysis and fabrication of a linear permanent magnet ...
MONOJIT SEAL
Linear permanent magnet synchronous machine; LPMSM—fabrication; design optimisation; finite-element ... induction motor (LIM) prototype was patented in 1890 [1]. Since then, linear ..... Also, for manual winding, more slot area is allotted to ...
High Voltage Seismic Generator
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
Increased voltage photovoltaic cell
Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)
1985-01-01
A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.
Inductance, electrically adjusted by semiconductor structure
Semenov А. А.
2012-08-01
Full Text Available A theoretical model of a passive flat inductor with electronic control is offered. Design charts of tank inductance and Q factor dependence on the forward bias voltage of n—i—p—i—n-structure, used as a specific core, the characteristics of which are regulated under the influence of an applied electric field, are presented. The comparison of design values with experimental features has shown their good correspondence with each other.
Stoll, R R
1968-01-01
Linear Algebra is intended to be used as a text for a one-semester course in linear algebra at the undergraduate level. The treatment of the subject will be both useful to students of mathematics and those interested primarily in applications of the theory. The major prerequisite for mastering the material is the readiness of the student to reason abstractly. Specifically, this calls for an understanding of the fact that axioms are assumptions and that theorems are logical consequences of one or more axioms. Familiarity with calculus and linear differential equations is required for understand
Intrinsic magnetic torque at low magnetic induction
Doria, M.M.; Oliveira, I.G. de.
1993-01-01
Using anisotropic London theory the intrinsic magnetic torque for extreme type II uniaxial superconductors for any value of the magnetic induction is obtained. It is considered the vortex lines straight and take into account the contribution of the supercurrents flowing inside the vortex core within the London theory. It is shown that the interline and intra line free energies give opposite torque contributions, the first drives the magnetic induction parallel to the superconductor's axis of symmetry and the second orthogonal to it. At high magnetic induction torque expression obtained generalizes V. Kogan's formula since it has no free parameters other than the anisotropy γ = m 1 /m 3 and the Ginzburg-Landau parameter κ. At low magnetic induction it is proposed a way to observe vortex chains effects in the total torque based on the fact that London theory is linear and the energy to make a single vortex line in space is independent of the magnetic induction. (author)
Discussion - a high voltage DC generator
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
Suppressing voltage transients in high voltage power supplies
Lickel, K.F.; Stonebank, R.
1979-01-01
A high voltage power supply for an X-ray tubes includes voltage adjusting means, a high voltage transformer, switch means connected to make and interrupt the primary current of the transformer, and over-voltage suppression means to suppress the voltage transient produced when the current is switched on. In order to reduce the power losses in the suppression means, an impedance is connected in the transformer primary circuit on operation of the switch means and is subsequently short-circuited by a switch controlled by a timer after a period which is automatically adjusted to the duration of the transient overvoltage. (U.K.)
Solow, Daniel
2014-01-01
This text covers the basic theory and computation for a first course in linear programming, including substantial material on mathematical proof techniques and sophisticated computation methods. Includes Appendix on using Excel. 1984 edition.
Liesen, Jörg
2015-01-01
This self-contained textbook takes a matrix-oriented approach to linear algebra and presents a complete theory, including all details and proofs, culminating in the Jordan canonical form and its proof. Throughout the development, the applicability of the results is highlighted. Additionally, the book presents special topics from applied linear algebra including matrix functions, the singular value decomposition, the Kronecker product and linear matrix equations. The matrix-oriented approach to linear algebra leads to a better intuition and a deeper understanding of the abstract concepts, and therefore simplifies their use in real world applications. Some of these applications are presented in detailed examples. In several ‘MATLAB-Minutes’ students can comprehend the concepts and results using computational experiments. Necessary basics for the use of MATLAB are presented in a short introduction. Students can also actively work with the material and practice their mathematical skills in more than 300 exerc...
Berberian, Sterling K
2014-01-01
Introductory treatment covers basic theory of vector spaces and linear maps - dimension, determinants, eigenvalues, and eigenvectors - plus more advanced topics such as the study of canonical forms for matrices. 1992 edition.
Searle, Shayle R
2012-01-01
This 1971 classic on linear models is once again available--as a Wiley Classics Library Edition. It features material that can be understood by any statistician who understands matrix algebra and basic statistical methods.
Benchmarking of Voltage Sag Generators
Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang
2012-01-01
The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...
Blaabjerg, Frede; Lee, Kyo Beum
2007-01-01
This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn......-on and turn-off times of switching devices, and on-state switching device voltage drop are modeled using PQR transformation and compensated using a reference current control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system...
Christofilos, N.C.; Polk, I.J.
1959-02-17
Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.
Transient voltage sharing in series-coupled high voltage switches
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.
Improved modeling of new three-phase high voltage transformer with magnetic shunts
Chraygane M.
2015-03-01
Full Text Available This original paper deals with a new approach for the study of behavior in nonlinear regime of a new three-phase high voltage power supply for magnetrons, used for the microwave generators in industrial applications. The design of this system is composed of a new three-phase leakage flux transformer supplying by phase a cell, composed of a capacitor and a diode, which multiplies the voltage and stabilizes the current. Each cell. in turn, supplies a single magnetron. An equivalent model of this transformer is developed taking into account the saturation phenomenon and the stabilization process of each magnetron. Each inductance of the model is characterized by a non linear relation between flux and current. This model was tested by EMTP software near the nominal state. The theoretical results were compared to experimental measurements with a good agreement. Relative to the current device, the new systemprovides gains of size, volume, cost of implementation and maintenance which make it more economical.
Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna
2017-01-01
This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... optimization. The proposed method is used to calculate the voltage bands and droop settings of PV inverters at each node by the supervisory controller. The local controller of each PV inverter implements the volt/var control and if necessary, the active power curtailment as per the received settings and based...... on measured local voltages. The advantage of the proposed method is that the calculated reactive power and active power droop settings enable fair contribution of the PV inverters at each node to the voltage regulation. Simulation studies are conducted using DigSilent Power factory software on a simplified...
Symmetric low-voltage powering system for relativistic electronic devices
Agafonov, A.V.; Lebedev, A.N.; Krastelev, E.G.
2005-01-01
A special driver for double-sided powering of relativistic magnetrons and several methods of localized electron flow forming in the interaction region of relativistic magnetrons are proposed and discussed. Two experimental installations are presented and discussed. One of them is designed for laboratory research and demonstration experiments at a rather low voltage. The other one is a prototype of a full-scale installation for an experimental research at relativistic levels of voltages on the microwave generation in the new integrated system consisting of a relativistic magnetron and symmetrical induction driver
High voltage pulsed cable design: a practical example
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.
High voltage pulsed cable design: a practical example
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
Low cost photomultiplier high-voltage readout system
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
Artificial intelligence techniques for voltage control
Ekwue, A.; Cheng, D.T.Y.; Macqueen, J.F.
1997-12-31
In electric power systems, the advantages of reactive power dispatching or optimisation include improved utilisation of reactive power sources and hence reduction in reactive power flows and real losses of the system; unloading of the system and equipment as a result of reactive flow reduction; the power factors of generation are improved and system security is enhanced; reduced voltage gradients and somewhat higher voltages which result across the system from improved operation; deferred capital investment is new reactive power sources as a result of improved utilisation of existing equipment; and for the National Grid Company plc (NGC), the main advantage is reduced out-of-merit operation. The problem of reactive power control has been studied and widely reported in the literature. Non-linear programming methods as well as linear programming techniques for constraint dispatch have been described. Static optimisation of reactive power sources by the use of sensitivity analysis was described by Kishore and Hill. Long range optimum var planning has been considered and the optimum amount and location of network reactive compensation so as to maintain the system voltage within the desired limits, while operating under normal and various insecurity states, have also been studied using several methods. The objective of this chapter is therefore to review conventional methods as well as AI techniques for reactive power control. (Author)
Sensing voltage across lipid membranes
Swartz, Kenton J.
2009-01-01
The detection of electrical potentials across lipid bilayers by specialized membrane proteins is required for many fundamental cellular processes such as the generation and propagation of nerve impulses. These membrane proteins possess modular voltage-sensing domains, a notable example being the S1-S4 domains of voltage-activated ion channels. Ground-breaking structural studies on these domains explain how voltage sensors are designed and reveal important interactions with the surrounding lipid membrane. Although further structures are needed to fully understand the conformational changes that occur during voltage sensing, the available data help to frame several key concepts that are fundamental to the mechanism of voltage sensing. PMID:19092925
High voltage high brightness electron accelerator with MITL voltage adder coupled to foilless diode
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
Induction linacs for heavy ion fusion research
Fessenden, T.J.; Avery, R.T.; Brady, V.; Bisognano, J.; Celata, C.; Chupp, W.W.; Faltens, A.; Hartwig, E.C.; Judd, D.L.; Keefe, D.; Kim, C.H.; Laslett, L.J.; Lee, E.P.; Rosenblum, S.S.; Smith, L.; Warwick, A.
1984-01-01
The new features of employing an induction linac as a driver for inertial fusion involve (1) transport of high-current low-emittance heavy ion beams. (2) multiple independently-focussed beams threading the same accelerator structure, and (3) synthesis of voltage waveforms to accomplish beam current amplification. A research program is underway at LBL to develop accelerators that test all these features with the final goal of producing an ion beam capable of heating matter to proportional70 eV. This paper presents a discussion of some properties of induction linacs and how they may be used for HIF research. Physics designs of the High Temperature Experiment (HTE) and the Multiple Beam Experiment (MBE) accelerators are presented along with initial concepts of the MBE induction units. (orig.)
Induction linacs for heavy ion fusion research
Fessenden, T.J.
1984-05-01
The new features of employing an induction linac as a driver for inertial fusion involve (1) transport of high-current low-emittance heavy ion beams, (2) multiple independently-focussed beams threading the same accelerator structure, and (3) synthesis of voltage waveforms to accomplish beam current amplification. A research program is underway at LBL to develop accelerators that test all these features with the final goal of producing an ion beam capable of heating matter to approx. 70 eV. This paper presents a discussion of some properties of induction linacs and how they may be used for HIF research. Physics designs of the High Temperature Experiment (HTE) and the Multiple Beam Experiment (MBE) accelerators are presented along with initial concepts of the MBE induction units.
Olive, David J
2017-01-01
This text covers both multiple linear regression and some experimental design models. The text uses the response plot to visualize the model and to detect outliers, does not assume that the error distribution has a known parametric distribution, develops prediction intervals that work when the error distribution is unknown, suggests bootstrap hypothesis tests that may be useful for inference after variable selection, and develops prediction regions and large sample theory for the multivariate linear regression model that has m response variables. A relationship between multivariate prediction regions and confidence regions provides a simple way to bootstrap confidence regions. These confidence regions often provide a practical method for testing hypotheses. There is also a chapter on generalized linear models and generalized additive models. There are many R functions to produce response and residual plots, to simulate prediction intervals and hypothesis tests, to detect outliers, and to choose response trans...
Alcaraz, J.
2001-01-01
After several years of study e''+ e''- linear colliders in the TeV range have emerged as the major and optimal high-energy physics projects for the post-LHC era. These notes summarize the present status form the main accelerator and detector features to their physics potential. The LHC era. These notes summarize the present status, from the main accelerator and detector features to their physics potential. The LHC is expected to provide first discoveries in the new energy domain, whereas an e''+ e''- linear collider in the 500 GeV-1 TeV will be able to complement it to an unprecedented level of precision in any possible areas: Higgs, signals beyond the SM and electroweak measurements. It is evident that the Linear Collider program will constitute a major step in the understanding of the nature of the new physics beyond the Standard Model. (Author) 22 refs
Edwards, Harold M
1995-01-01
In his new undergraduate textbook, Harold M Edwards proposes a radically new and thoroughly algorithmic approach to linear algebra Originally inspired by the constructive philosophy of mathematics championed in the 19th century by Leopold Kronecker, the approach is well suited to students in the computer-dominated late 20th century Each proof is an algorithm described in English that can be translated into the computer language the class is using and put to work solving problems and generating new examples, making the study of linear algebra a truly interactive experience Designed for a one-semester course, this text adopts an algorithmic approach to linear algebra giving the student many examples to work through and copious exercises to test their skills and extend their knowledge of the subject Students at all levels will find much interactive instruction in this text while teachers will find stimulating examples and methods of approach to the subject
Inductive Monitoring System (IMS)
National Aeronautics and Space Administration — IMS: Inductive Monitoring System The Inductive Monitoring System (IMS) is a tool that uses a data mining technique called clustering to extract models of normal...
Heat-pump performance: voltage dip/sag, under-voltage and over-voltage
William J.B. Heffernan
2014-12-01
Full Text Available Reverse cycle air-source heat-pumps are an increasingly significant load in New Zealand and in many other countries. This has raised concern over the impact wide-spread use of heat-pumps may have on the grid. The characteristics of the loads connected to the power system are changing because of heat-pumps. Their performance during under-voltage events such as voltage dips has the potential to compound the event and possibly cause voltage collapse. In this study, results from testing six heat-pumps are presented to assess their performance at various voltages and hence their impact on voltage stability.
Inductive Reasoning and Writing
Rooks, Clay; Boyd, Robert
2003-01-01
Induction, properly understood, is not merely a game, nor is it a gimmick, nor is it an artificial way of explaining an element of reasoning. Proper understanding of inductive reasoning--and the various types of reasoning that the authors term inductive--enables the student to evaluate critically other people's writing and enhances the composition…
Passive longitudinal phase space linearizer
P. Craievich
2010-03-01
Full Text Available We report on the possibility to passively linearize the bunch compression process in electron linacs for the next generation x-ray free electron lasers. This can be done by using the monopole wakefields in a dielectric-lined waveguide. The optimum longitudinal voltage loss over the length of the bunch is calculated in order to compensate both the second-order rf time curvature and the second-order momentum compaction terms. Thus, the longitudinal phase space after the compression process is linearized up to a fourth-order term introduced by the convolution between the bunch and the monopole wake function.
Sun, Xiaofeng; Zeng, Jian; Chen, Zhe
2013-01-01
, and analyze the harmonic voltage propagation caused by the background harmonic voltage in power systems. Then, a new strategy is proposed for the site selection of resistive active power filter to damp the background harmonic voltage in power systems. Experiments have been performed to verify the theoretical......Series resonance between capacitance and line inductance may magnify background harmonic voltage and worsen the harmonic voltage distortion in power systems. To solve this problem, in this paper, the transmission line theory is used to set up the distributed parameter model of power system feeders...
Ultra Fast, High Rep Rate, High Voltage Spark Gap Pulser
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
Boldea, Ion
2002-01-01
Often called the workhorse of industry, the advent of power electronics and advances in digital control are transforming the induction motor into the racehorse of industrial motion control. Now, the classic texts on induction machines are nearly three decades old, while more recent books on electric motors lack the necessary depth and detail on induction machines.The Induction Machine Handbook fills industry's long-standing need for a comprehensive treatise embracing the many intricate facets of induction machine analysis and design. Moving gradually from simple to complex and from standard to
Micallef, A.; Apap, M.; Spitero-Stanies, C.
2012-01-01
This paper focuses on the islanded operation of microgrids. In this mode of operation, the microsources are required to cooperate autonomously to regulate the local grid voltage and frequency. Droop control is typically used to achieve this autonomous voltage and frequency regulation. Inverters...... having LCL output filters would cause voltage distortion to be present at the PCC of the local load when non-linear current is supplied to the load due to the voltage drop across the grid side inductor. Techniques to reduce the output voltage distortion typically consist of installing either passive...
High voltage isolation transformer
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.
Richards, J.A.
1977-01-01
A linear particle accelerator which provides a pulsed beam of charged particles of uniform energy is described. The accelerator is in the form of an evacuated dielectric tube, inside of which a particle source is located at one end of the tube, with a target or window located at the other end of the dielectric tube. Along the length of the tube are externally located pairs of metal plates, each insulated from each other in an insulated housing. Each of the plates of a pair are connected to an electrical source of voltage of opposed polarity, with the polarity of the voltage of the plates oriented so that the plate of a pair, nearer to the particle source, is of the opposed polarity to the charge of the particle emitted by the source. Thus, a first plate about the tube located nearest the particle source, attracts a particle which as it passes through the tube past the first plate is then repelled by the reverse polarity of the second plate of the pair to continue moving towards the target
A voltage biased superconducting quantum interference device bootstrap circuit
Xie Xiaoming; Wang Huiwu; Wang Yongliang; Dong Hui; Jiang Mianheng; Zhang Yi; Krause, Hans-Joachim; Braginski, Alex I; Offenhaeusser, Andreas; Mueck, Michael
2010-01-01
We present a dc superconducting quantum interference device (SQUID) readout circuit operating in the voltage bias mode and called a SQUID bootstrap circuit (SBC). The SBC is an alternative implementation of two existing methods for suppression of room-temperature amplifier noise: additional voltage feedback and current feedback. Two circuit branches are connected in parallel. In the dc SQUID branch, an inductively coupled coil connected in series provides the bias current feedback for enhancing the flux-to-current coefficient. The circuit branch parallel to the dc SQUID branch contains an inductively coupled voltage feedback coil with a shunt resistor in series for suppressing the preamplifier noise current by increasing the dynamic resistance. We show that the SBC effectively reduces the preamplifier noise to below the SQUID intrinsic noise. For a helium-cooled planar SQUID magnetometer with a SQUID inductance of 350 pH, a flux noise of about 3 μΦ 0 Hz -1/2 and a magnetic field resolution of less than 3 fT Hz -1/2 were obtained. The SBC leads to a convenient direct readout electronics for a dc SQUID with a wider adjustment tolerance than other feedback schemes.
A two-layer linear piezoelectric micromotor.
Li, Xiaotian; Ci, Penghong; Liu, Guoxi; Dong, Shuxiang
2015-03-01
A first bending (B1) mode two-layer piezoelectric ultrasonic linear micromotor has been developed for microoptics driving applications. The piezo-vibrator of the micromotor was composed of two small Pb(Zr,Ti)O3 (PZT-5) plates, with overall dimensions and mass of only 2.0 × 2.0 × 5.0 mm(3) and 0.2 g, respectively. The proposed micromotor could operate either in single-phase voltage (standing wave) mode or two-phase voltage (traveling wave) mode to drive a slider via friction force to provide bidirectional linear motion. A large thrust of up to 0.30 N, which corresponds to a high unit volume direct driving force of 15 mN/mm(3), and a linear movement velocity of up to 230 mm/s were obtained under an applied voltage of 80 Vpp at the B1 mode resonance frequency of 174 kHz.
Numerical identifiability of the parameters of induction machines
Corcoles, F.; Pedra, J.; Salichs, M. [Dep. d' Eng. Electrica ETSEIB. UPC, Barcelona (Spain)
2000-08-01
This paper analyses the numerical identifiability of the electrical parameters of induction machines. Relations between parameters and the impossibility to estimate all of them - when only external measures are used: voltage, current, speed and torque - are shown. Formulations of the single and double-cage induction machine, with and without core losses in both models, are developed. The proposed solution is the formulation of machine equations by using the minimum number of parameters (which are identifiable parameters). As an application example, the parameters of a double-cage induction machine are identified using steady-state measurements corresponding to different angular speeds. (orig.)
Karloff, Howard
1991-01-01
To this reviewer’s knowledge, this is the first book accessible to the upper division undergraduate or beginning graduate student that surveys linear programming from the Simplex Method…via the Ellipsoid algorithm to Karmarkar’s algorithm. Moreover, its point of view is algorithmic and thus it provides both a history and a case history of work in complexity theory. The presentation is admirable; Karloff's style is informal (even humorous at times) without sacrificing anything necessary for understanding. Diagrams (including horizontal brackets that group terms) aid in providing clarity. The end-of-chapter notes are helpful...Recommended highly for acquisition, since it is not only a textbook, but can also be used for independent reading and study. —Choice Reviews The reader will be well served by reading the monograph from cover to cover. The author succeeds in providing a concise, readable, understandable introduction to modern linear programming. —Mathematics of Computing This is a textbook intend...
Application of SMES in wind farm to improve voltage stability
Shi, J.; Tang, Y.J.; Ren, L.; Li, J.D.; Chen, S.J.
2008-01-01
For the wind farms introducing doubly fed induction generators (DFIGs), voltage stability is an essential issue which influences their widely integration into the power grid. This paper proposes the application of superconducting magnetic energy storage (SMES) in the power system integrated with wind farms. SMES can control the active and reactive power flow, realizing the operation in four quadrants independently. The introducing of SMES can smooth the output power flow of the wind farms, and supply dynamic voltage support. Using MATLAB/SIMULINK, the models of the DFIG, the power grid connected and the SMES are created. Simulation results show that the voltage stability of the power system integrated with wind farms can be improved considerably
Induction linacs as radiation processors
Birx, D.L.
1986-01-01
Experiments at the Lawrence Livermore National Laboratory (LLNL), University of California, in conjunction with the University of California at Davis have shown induction linear accelerators (linacs) to be suitable for radiation processing of food. Here we describe how it might be possible to optimize this technology developded for the Department of Defense to serve in radiation processing. The possible advantages of accelerator-produced radiation over the use of radioisotopes include a tailor-made energy spectrum that can provide much deeper penetration and thereby better dose uniformity
Valeev, R.I.; Nikiforov, M.G.; Kharchenko, A.F.
1988-01-01
The design is described and the test results of a four-channel pulse-voltage generator with maximum output voltage 200 kV are presented. The measurement results of generator triggering time depending on the value and polarity of the triggering voltage pulse for different triggering circuits are presented. The tests have shown stable triggering of all four channels of the generator in the range up to 40 % from selfbreakdown voltage. The generator triggering delay in the given range is <25 ns, asynchronism in channel triggering is <±1 ns
Low voltage initiation of damaging arcs between electrical contacts
Cuthrell, R.E.
1975-07-01
Metallic arcs were found to precede the firm contacting of electrical contacts which were closed without bounce. When the open-circuit voltages were below the ionization potential, the initiation of these arcs was found to depend on the presence of asperities on the surfaces and on asperity contracting, melting, and pinching off by magnetic forces. The arc is thought to be initiated inductively when the molten metallic asperity contact is pinched off, and the electrode damage is similar to that produced by the arcing of opening contacts. Arcing could not be produced for exceptionally smooth surfaces, or, for rough surfaces when the open-circuit potential was below the melting voltages of the electrode metals. In order to prevent damage to contact surfaces by melting or arcing, it is suggested that test potentials be limited to below the melting voltages, that the current be limited, the test circuits be designed to prevent inductively generated high voltage transients, and the contact surfaces be very smooth. In order to facilitate arc initiation in arc welding applications, it is suggested that the surfaces of electrodes and work pieces be roughened. (U.S.)
Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through
Yun Wang
2014-06-01
Full Text Available This paper presents a fast coordinated control scheme of the rotor side converter (RSC, the Direct Current (DC chopper and the grid side converter (GSC of doubly fed induction generator (DFIG wind turbine generators (WTGs to improve the low voltage ride through (LVRT and high voltage ride through (HVRT capability of the DFIG WTGs. The characteristics of DFIG WTGs under voltage sags and swells were studied focusing on the DFIG WTG stator flux and rotor voltages during the transient periods of grid voltage changes. The protection schemes of the rotor crowbar circuit and the DC chopper circuit were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were verified by time domain simulations using Matlab-Simulink.
Inductance position sensor for pneumatic cylinder
Pavel Ripka
2018-04-01
Full Text Available The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the inductance is increasing with inserting rod due to the rod permeability. This mode has disadvantage of slow response to piston movement and also high temperature sensitivity. At the frequency of 45 Hz the inductance is position independent, as the permeability effect is compensated by the eddy current effect. At higher frequencies eddy current effects in the rod prevail, the inductance is decreasing with inserting rod. In this mode the sensitivity is smaller but the sensor response is fast and temperature stability is better. We show that FEM simulation of this sensor using measured material properties gives accurate results, which is important for the sensor optimization such as designing the winding geometry for the best linearity.
Inductance position sensor for pneumatic cylinder
Ripka, Pavel; Chirtsov, Andrey; Mirzaei, Mehran; Vyhnanek, Jan
2018-04-01
The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the inductance is increasing with inserting rod due to the rod permeability. This mode has disadvantage of slow response to piston movement and also high temperature sensitivity. At the frequency of 45 Hz the inductance is position independent, as the permeability effect is compensated by the eddy current effect. At higher frequencies eddy current effects in the rod prevail, the inductance is decreasing with inserting rod. In this mode the sensitivity is smaller but the sensor response is fast and temperature stability is better. We show that FEM simulation of this sensor using measured material properties gives accurate results, which is important for the sensor optimization such as designing the winding geometry for the best linearity.
Moderately nonlinear diffuse-charge dynamics under an ac voltage.
Stout, Robert F; Khair, Aditya S
2015-09-01
The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of V_{o}/(k_{B}T/e), where V_{o} is the amplitude of the driving voltage and k_{B}T/e is the thermal voltage with k_{B} as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D/λ_{D}L, where D is the ion diffusivity, λ_{D} is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O(V_{o}^{3}) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in V_{o}. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing V_{o}. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer.
Moderately nonlinear diffuse-charge dynamics under an ac voltage
Stout, Robert F.; Khair, Aditya S.
2015-09-01
The response of a symmetric binary electrolyte between two parallel, blocking electrodes to a moderate amplitude ac voltage is quantified. The diffuse charge dynamics are modeled via the Poisson-Nernst-Planck equations for a dilute solution of point-like ions. The solution to these equations is expressed as a Fourier series with a voltage perturbation expansion for arbitrary Debye layer thickness and ac frequency. Here, the perturbation expansion in voltage proceeds in powers of Vo/(kBT /e ) , where Vo is the amplitude of the driving voltage and kBT /e is the thermal voltage with kB as Boltzmann's constant, T as the temperature, and e as the fundamental charge. We show that the response of the electrolyte remains essentially linear in voltage amplitude at frequencies greater than the RC frequency of Debye layer charging, D /λDL , where D is the ion diffusivity, λD is the Debye layer thickness, and L is half the cell width. In contrast, nonlinear response is predicted at frequencies below the RC frequency. We find that the ion densities exhibit symmetric deviations from the (uniform) equilibrium density at even orders of the voltage amplitude. This leads to the voltage dependence of the current in the external circuit arising from the odd orders of voltage. For instance, the first nonlinear contribution to the current is O (Vo3) which contains the expected third harmonic but also a component oscillating at the applied frequency. We use this to compute a generalized impedance for moderate voltages, the first nonlinear contribution to which is quadratic in Vo. This contribution predicts a decrease in the imaginary part of the impedance at low frequency, which is due to the increase in Debye layer capacitance with increasing Vo. In contrast, the real part of the impedance increases at low frequency, due to adsorption of neutral salt from the bulk to the Debye layer.
Temporary over voltages in the high voltage networks
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)
High average-power induction linacs
Prono, D.S.; Barrett, D.; Bowles, E.; Caporaso, G.J.; Chen, Yu-Jiuan; Clark, J.C.; Coffield, F.; Newton, M.A.; Nexsen, W.; Ravenscroft, D.; Turner, W.C.; Watson, J.A.
1989-01-01
Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of ∼ 50-ns duration pulses to > 100 MeV. In this paper the authors report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs
High average-power induction linacs
Prono, D.S.; Barrett, D.; Bowles, E.
1989-01-01
Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of /approximately/ 50-ns duration pulses to > 100 MeV. In this paper we report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs
Ward, Kevin S.; Long, Finis W.; Sinebryukhov, Vadim A.; Kim, Alexandre A.; Wakeland, Peter Eric; McKee, G. Randall; Woodworth, Joseph Ray; McDaniel, Dillon Heirman; Fowler, William E.; Mazarakis, Michael Gerrassimos; Porter, John Larry Jr.; Struve, Kenneth William; Stygar, William A.; LeChien, Keith R.; Matzen, Maurice Keith
2010-01-01
Sandia National Laboratories, Albuquerque, N.M., USA, in collaboration with the High Current Electronic Institute (HCEI), Tomsk, Russia, is developing a new paradigm in pulsed power technology: the Linear Transformer Driver (LTD) technology. This technological approach can provide very compact devices that can deliver very fast high current and high voltage pulses straight out of the cavity with out any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The load may be a vacuum electron diode, a z-pinch wire array, a gas puff, a liner, an isentropic compression load (ICE) to study material behavior under very high magnetic fields, or a fusion energy (IFE) target. This is because the output pulse rise time and width can be easily tailored to the specific application needs. In this paper we briefly summarize the developmental work done in Sandia and HCEI during the last few years, and describe our new MYKONOS Sandia High Current LTD Laboratory.
detection of static eccentricity fault in saturated induction motors
2013-06-30
Jun 30, 2013 ... The air gap magnetic field contains full information of the stator condition and ... voltage asymmetry [21] wound rotor phase disconnection [22], ... TSFE analysis of induction motor based circuit-coupled method ... The last term represents current induced in conducting material when flux changes with time.
The Design and Characterization of a Prototype Wideband Voltage Sensor Based on a Resistive Divider.
Garnacho, Fernando; Khamlichi, Abderrahim; Rovira, Jorge
2017-11-17
The most important advantage of voltage dividers over traditional voltage transformers is that voltage dividers do not have an iron core with non-linear hysteresis characteristics. The voltage dividers have a linear behavior with respect to over-voltages and a flat frequency response larger frequency range. The weak point of a voltage divider is the influence of external high-voltage (HV) and earth parts in its vicinity. Electrical fields arising from high voltages in neighboring phases and from ground conductors and structures are one of their main sources for systematic measurement errors. This paper describes a shielding voltage divider for a 24 kV medium voltage network insulated in SF6 composed of two resistive-capacitive dividers, one integrated within the other, achieving a flat frequency response up to 10 kHz for ratio error and up to 5 kHz for phase displacement error. The metal shielding improves its immunity against electric and magnetic fields. The characterization performed on the built-in voltage sensor shows an accuracy class of 0.2 for a frequency range from 20 Hz to 5 kHz and a class of 0.5 for 1 Hz up to 20 Hz. A low temperature effect is also achieved for operation conditions of MV power grids.
Currents and voltages in the MFTF coils during the formation of a normal zone
Owen, E.W.
1980-08-01
Expressions are obtained for the currents and voltages in a pair of inductively coupled superconducting coils under two conditions: formation of a normal zone and during a change in the level of the current in one coil. A dump resistor of low resistance and a detector bridge is connected across each coil. Calculated results are given for the MFTF coils. The circuit equations during formation of a normal zone are nonlinear and time-varying, consequently, only a series solution is possible. The conditions during a change in current are more easily found. After the transient has died away, the voltages in the coil associated with the changing source are all self-inductive, while the voltages in the other coil are all mutually inductive
High-Efficiency Isolated Boost DCDC Converter for High-Power Low-Voltage Fuel-Cell Applications
Nymand, Morten; Andersen, Michael A. E.
2010-01-01
high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing...
A voltage to frequency converter for astronomical photometry
Dunham, E.; Elliot, J. L.
1978-01-01
A voltage to frequency converter (VFC) for general use with photomultipliers is described. For high light levels, when the dead-time corrections for a photon counter would be excessive, the VFC maintains a linear response and allows the recording of data at high time resolution. Results of laboratory tests are given for the signal-to-noise characteristics, linearity, stability, and transient response of the VFC when used in conjunction with EMI 9658 and RCA C31034 photomultipliers.
New method for determining avalanche breakdown voltage of silicon photomultipliers
Chirikov-Zorin, I.
2017-01-01
The avalanche breakdown and Geiger mode of the silicon p-n junction is considered. A precise physically motivated method is proposed for determining the avalanche breakdown voltage of silicon photomultipliers (SiPM). The method is based on measuring the dependence of the relative photon detection efficiency (PDE rel ) on the bias voltage when one type of carriers (electron or hole) is injected into the avalanche multiplication zone of the p-n junction. The injection of electrons or holes from the base region of the SiPM semiconductor structure is performed using short-wave or long-wave light. At a low overvoltage (1-2 V) the detection efficiency is linearly dependent on the bias voltage; therefore, extrapolation to zero PDE rel value determines the SiPM avalanche breakdown voltage with an accuracy within a few millivolts. [ru
Reduction of ripple voltage in a dynamitron
Langsdorf, A. Jr.
1982-01-01
We determined that a precise neutralization of the RF ripple voltage on the high-voltage terminal of a Dynamitron has previously been prevented by a nonegligible phase shift of RF currents in the two halves of the approx. 100-kHz class C oscillator tank circuit, which is actually constituted of two slightly unequal high-Q coupled circuits because it has two ground points: the inescapable center-tap-ground in the capacitive legs and a center-tap-ground lead to the induction coil. The latter is needed to prevent damage by flashover transients; equivalent to its removal was the adjusting of RF ground return current to a null by aid of a current transformer on this lead and the suitable adjusting of trimmer capacitance. While the phase shift was thus held to a null, the actual ripple amplitude on the hv terminal was minimized by adjusting additional trimmer capacitances installed in the terminal of the machine. Then p/p 100-kHz ripple at 2-MV dc output was reduced to about 50V and RMS resolution by (p,#betta#) resonance threshold data near 1 MV was about 250 V. The limit to resolution has various causes including mechanical vibrations and unbalanced harmonics of the RF