bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of induction motor speed sensorless vector control to railway vehicle traction
Authors: Kondo Keiichiro , Yuki Kazuaki 
Published: July 2007

AbstractPulse generators (PGs) are equipped to detect the rotor frequency of induction traction motors for torque control in railway vehicle traction field. Eliminating PGs is preferable from the viewpoints of increasing the reliability of the traction system, reduction of both the initial and maintenance cost, and downsizing induction traction motors. Expecting those advantages, we have been studying the application of a sensorless control method to induction traction motor control. Prior to some reports of studies and tests to apply speed sensorless strategy to railway vehicle traction we launched ideas to apply the speed sensorless control strategy and results of the studies and tests. In this paper, we present the novel control method for railway vehicle traction and some results of theoretical study and tests. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 69–77, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20273
A new current control method for energy‐efficient/wide‐speed‐range drive of permanent magnet synchronous motor
Authors: Shinnaka Shinji 
Published: July 2007

AbstractThis paper proposes a new current control method for energy‐efficient and/or wide‐speed‐range drive of salient‐pole permanent magnet synchronous motors. The proposed method is distinguished from conventional ones by the following features. (1) The original command is a signed current norm. (2) The exact d‐axis and q‐axis current commands that perform energy‐efficient and/or wide‐speed‐range drive are analytically and simply determined from the singed current norm command. (3) For speed control mode, the system turns out to be nonlinear, but its stability can be guaranteed based on Popov's stability theorem. (4) It can be applied for a mode similar to torque control. (5) Current limitation can be carried out accurately but very simply. Concrete analytical d‐axis and q‐axis current commands are presented, which satisfy exactly one of three optimum current control codes such as maximum torque, maximum power factor, and voltage limitation. A design method for PI speed controller that guarantees system stability is also presented. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 66–77, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20305
Computation of heat loads in cryogenic parts of high‐temperature superconductor synchronous machines
Authors: Taku Seigo , Maki Naoki 
Published: July 2007

AbstractHigh‐temperature superconductor (HTS) synchronous machines are expected to have higher efficiency and smaller size than normal conductor synchronous machines, and are being developed mainly in the USA and Germany. This paper describes a computation method of heat loads in cryogenic parts of HTS synchronous machines, and the evaluation study results of heat loads in HTS synchronous motors for blowers, in which Bi‐2223 is used at 30 K, using the computation method. From the evaluated heat loads, the required capacity of the refrigerator for HTS synchronous machines may be determined. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 62–68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20338
Characteristics comparison of high‐frequency multilevel inverter connected with filter inverters
Authors: Iwaya Kazuki , Noguchi Toshihiko 
Published: July 2007

AbstractThis paper presents a characteristics comparison of a high‐frequency multilevel inverter connected with small‐ capacity filter inverters. In general, PWM inverters require a low‐pass filter in order to reduce switching harmonics. However, in the high‐frequency systems such as class D power amplifiers, the cutoff frequency of the low‐pass filter must be set at high frequency. Thus, harmonic distortion of the output voltage is enlarged to a harmful level. Increasing the number of output voltage levels is effective in reducing the harmonic distortion of the output voltage and the low‐pass filter size. The proposed systems consist of a five‐level inverter and several cascade‐connected low‐voltage full bridge inverters without any external DC power sources for filtering the output voltage. The five‐level inverter generates a stepwise waveform with five‐level voltage, and the low‐voltage filter inverter superimposes harmonic components to compensate for the voltage waveform distortion. Therefore, the proposed system can reduce its total switching loss and can increase the number of the output voltage levels. In this paper, the effectiveness of the proposed systems is verified through several experiments. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 58–65, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20373
Signal control by successive updating of control parameters based on prediction of traffic flow
Authors: Oda Toshihiko 
Published: July 2007

AbstractIn traditional coordinated traffic signal control on an urban road network, the following two problems occur. First, the conventional method involves a time lag between traffic measurement and signal control. Second, an abrupt switching of control parameters throws the traffic flow into disorder.This paper proposes a new approach to avoid these problems. We increase the frequency of switching. The control parameters are switched as frequently as every two cycles. At the time of switching, minor variations of the ongoing plan are generated. For each variation of plan, traffic delay at each intersection is predicted based on measured traffic data at upstream detectors. Then the plan minimizing the delay is chosen to be the control parameters in the next cycle. In order to evaluate the validity of this approach, experiments were carried out using a traffic simulator. The experiments indicate that the proposed method reduces the queue length significantly, compared with the conventional method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 49–57, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20391
Determination of optimal sending voltage profile in distribution systems with distributed generators
Authors: Hayashi Yasuhiro , Matsuki Junya , Suzuki Ryoji , Muto Eiji 
Published: July 2007

AbstractSending voltage profile of distribution feeder is controlled by changing a tap of distribution transformer. In a distribution network with distributed generators, for reasons of effect of reversed flows from them and existence of a great number of sending voltage profile candidates, it is not easy to control sending voltage profile within the acceptable voltage limit. In this paper, in order to determine the optical sending voltage profile of distribution transformer in a distribution network with distributed generators, the authors propose a new method to determine the optimal sending voltage profile so as to minimize the total number of tap position's change per day under constraints of acceptable voltage limit. In the proposed method, after calculating acceptable range of three‐phase voltage of distribution feeder, the optimal profile of tap position within the calculated acceptable voltage range is determined among these candidates by using reduced ordered binary decision diagram (ROBDD) which is an efficient enumeration algorithm. In order to check the validity of the proposed method, numerical simulations are carried out for a distribution network model with a distributed generator. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 16–24, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20393
Position sensorless control of interior permanent magnet synchronous motor using extended electromotive force
Authors: Tanaka Koji , Miki Ichiro 
Published: July 2007

AbstractDriving a permanent magnet synchronous motor (PMSM) requires the rotor position information to control the motor torque, and this is generally detected by mechanical position sensors such as an encoder or a resolver. However, these sensors increase the machine size and the cost of the drive, and reduce reliability of the system. Therefore, many papers about position sensorless drive method of PMSM have been published. This paper presents a position sensorless control of interior permanent magnet synchronous motor (IPMSM). A mathematical model of IPMSM using the extended electromotive force (EMF) in the rotating reference frame is utilized to estimate the rotor speed and position. This model has a simple structure integrating position information into the extended EMF term. Therefore, the sensorless control based on the mathematical motor model can be implemented simply. The estimation method proposed is based on the principle that the error of the current is proportional to that of extended EMF. This method was carried out using a 6‐pole, 400‐W, 1750 r/min test motor system. It was found that sensorless speed control was achieved from 80 r/min to 1800 r/min under 0 to 100%loads. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 41–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20406
Synchronous averaging for asynchronous sampling data
Authors: Noro Yuichi , Kuno Kazuhiro 
Published: July 2007

AbstractThe progress of digital audio technology has enabled the familiar use of products such as CD and DAT in acoustic measurement. For example, a signal reproduced with a CD player is inputted into a subject for measurement and a DAT recorder records its response. However, the sampling cannot be synchronized completely with the input signal, although both nominal sample rates are set up equally, because the player and recorder work independently. The most popular solution is to use software to perform the synchronous addition after converting the recorded signal into the original sampling rate. However, the rate conversion also has an error due to the windowing in the high‐frequency region of the processed signal. This paper proposes a new method for averaging asynchronous sampling data to solve these problems. To evaluate performance, the transfer function of only measuring equipment estimated from asynchronous sampling data was compared with the measurement results in synchronous sampling conditions. Both results agreed within 0.1 dB, so the effectiveness of the new method was confirmed. In measuring the frequency response of a BPF when white noise is introduced, the proposed method was compared with the method using rate conversion. As a result, the noise reduction was almost the same, and the processing time was reduced to about one‐fourth. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 33– 41, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20455
Feature extraction by supervised independent component analysis based on category information
Authors: Takabatake Hiroki , Kotani Manabu , Ozawa Seiichi 
Published: July 2007

AbstractIndependent component analysis (ICA) is a technique of transforming observation signals into their unknown independent components; hence, ICA has often been applied to blind signal separation problems. In this application, it is expected that the obtained independent components extract essential information of independent signal sources from input data in an unsupervised fashion. Based on such characteristics, ICA is currently utilized as a feature extraction method for images and sounds for recognition purposes. However, since ICA is an unsupervised learning, the obtained independent components are not always useful in recognition. To overcome this problem, we propose a supervised approach to ICA using category information. The proposed method is implemented in a conventional three‐layered neural network, but its objective function to be minimized is defined not only for the output layer but also for the hidden layer. The objective function consists of the following two terms: one evaluates the kurtosis of hidden unit outputs and the other evaluates the error between output signals and their teacher signals. The experiments are performed using several standard datasets to evaluate performance of the proposed algorithm. It is confirmed that a higher recognition accuracy is attained by the proposed method as compared with a conventional ICA algorithm. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 25–32, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20522
A kinematic and dynamic analysis on orthotic gait of paraplegics
Authors: Kagawa Takahiro , Fukuda Hiroshi , Uno Yoji 
Published: July 2007

AbstractIn this study, we attempt to quantify the relationship between significant arm‐clutch loading, leg restriction, and motor paralysis, and analyze lumbar joint trajectories in the orthotic gait of paraplegic subjects and in the ordinary and orthotic gaits of a normal subject, by using an inverted pendulum model. With leg restriction, the trajectories are located in front of an equilibrium point of the inverted pendulum, and the loading is higher due to the influence of the gravity moment. Comparing the trajectories of paraplegic and normal gait with orthosis in the horizontal plane, the trajectory in the paraplegic subjects was rectilinear, while that in the normal subject was curved in the direction toward the equilibrium point. The loading is lower in the curved trajectory than in the straight trajectory because of the trade‐off between gravity and inertia. These results suggest that the increase in the distance between the trunk movement and the equilibrium point of the inverted pendulum results in significant loading due to leg restriction and motor paralysis in the orthotic gait of paraplegics. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 10– 21, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20533
Experimental study on the Unified Power Flow Controller
Authors: Matsuki Junya , Hayashi Yasuhiro , Kitajima Shunsuke , Takahashi Masahiro , Murata Kenji 
Published: July 2007

AbstractThis paper presents the results of experimental study on the performance of a Unified Power Flow Controller (UPFC), one of the FACTS (Flexible AC Transmission Systems) controllers. A laboratory‐scale UPFC was manufactured and installed on a laboratory electric power system to investigate its multifunctional capabilities as a power flow controller. The UPFC consists of two 4.5‐kVA, 200‐V back‐to‐back voltage‐sourced converters, labeled “Converter 1” and “Converter 2,” operated from a common DC link provided by a DC storage capacitor of 380 V. It can provide independent control of both the real and reactive power flow in the line. Tests were performed to examine the capabilities of the UPFC, under one‐machine connected to an infinite‐bus system. Steady‐state responses under various kinds of operating conditions were measured and analyzed. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 8– 15, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20538
Theoretical study of methods for improving the energy efficiency of NOx removal from diesel exhaust gases by silent discharge
Authors: Shoyama Taiji , Yoshioka Yoshio 
Published: July 2007

AbstractTo improve the NO removal performance in silent discharge process, we investigated the influence of physical parameters such as current density, channel radius, and pulse duration of one micro‐discharge under a constant reduced electric field strength. The influence of micro‐discharge occurrence locations was also discussed. In order to analyze the NO removal process, we assumed that the pulse micro‐discharges occur repeatedly at the same location in static gas and that the chemical reactions induced by micro‐discharge form many radicals, which react with pollutants and by‐products. The conclusions we obtained are that lower current density, smaller discharge radius, and shorter discharge duration improve NO removal efficiency. These results also mean that the lower discharge energy of one micro‐discharge and the larger number of parallel micro‐discharges increase the NO removal performance. Therefore, making the area of one micro‐discharge small is a desirable way to improve the NO removal performance. Thus, we think that the glow‐like discharge might be more effective than the streamer‐like discharge mode. Next, using the two‐dimensional model, which considered the influence of gas flow, we found that the repeated micro‐discharges at different positions are very effective to increase the De‐NOx performance. The reason is that the reaction of NO2+O→NO+O2 and ozone dissociation reactions are suppressed by the movement of the location of micro discharges. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 1–9, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20556
Plasma generation at atmospheric pressure using a high‐power microwave beam and its application to rocket propulsion
Authors: Oda Yasuhisa , Komurasaka Kimiya , Takahashi Koji , Kasugai Atsushi , Imai Tsuyoshi , Sakamoto Keishi 
Published: July 2007

AbstractExperiments on microwave plasma generation and its application to microwave beamed energy propulsion were conducted using a 1‐MW‐class, 170‐GHz gyrotron. The microwave beam was focused using a parabola reflector and plasma was initiated near the focal point in the ambient air. Plasma propagated upstream in the microwave beam channel while absorbing microwaves. Its propagation velocity was supersonic when the microwave power density was greater than 75 kW/cm2. The propulsive impulse was measured using a cone‐cylinder‐shaped thruster model. As a result, the maximum momentum coupling coefficient was obtained at a certain plasma propagation distance. In addition, a larger momentum coupling coefficient was obtained when plasma was propagated at a supersonic velocity. This is because supersonic plasma propagation forms a strong shock wave, resulting in an efficient pressure increase. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 1– 7, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20573
Eddy current flaw testing probe with high performance in detecting flaws during in‐service inspection of tubing
Authors: Koyama Kiyoshi , Hoshikawa Hiroshi 
Published: July 2007

AbstractEddy current flaw testing that uses changes in the impedance of the test coil as an electromagnetic field interacts with the test material is a nondestructive testing method. It can be used to inspect test material at high speed without bringing the test coil into contact with the test material. Therefore, it is widely used for product inspection. In the inspection of heat exchanger tubing in power plants and chemical plants, eddy current flaw testing is performed by using an inner probe, because of the structural restrictions of such plants. However, high levels of wobble noise and support plate noise occur in the conventional method using a rotating pancake coil. The authors therefore propose new minimal‐noise eddy current inner probes. Two new types of probes have been developed: one for detecting axial flaws and the other for detecting circumference flaws. These probes can detect flaws with a low level of noise. The phase of the flaw signal by the new probes changes according to the flaw depth. As a result, the signal phase by the new probes can be used for evaluating the depth of surface flaws. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 52–61, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20605
Why are Phosphole Oxides Unstable? The Phenomenon of Antiaromaticity as a Destabilizing Factor
Authors: Mucsi Zoltán , Keglevich György 
Published: July 2007

AbstractIt is shown that the great instability of phosphole oxides can be attributed to their antiaromatic characters. The aromatic–antiaromatic switch in the course of the oxidation of phospholes, which may be fine‐tuned by P substituents, increases the reactivity toward dimerisation, leading to the corresponding 7‐phosphanorbornene rings. The degree of antiaromaticity of these stable compounds is examined and quantified on a linear aromatic and antiaromatic scale. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Linear versus Angular Fischer Indole Annulation: Relative Configuration Determines Regioselectivity
Authors: Diedrich Claas Lüder , Frey Wolfgang , Christoffers Jens 
Published: July 2007

AbstractFischer indole synthesis with bicyclic ketones yields regioselectively linear annulated tetracyclic products when starting from ketones with a relative trans configuration. On the other hand, starting materials with a relative cis configuration give exclusively angular annulated indole derivatives. The starting materials were prepared in optically active form in three steps by a sequence of asymmetric Michael reaction, aldol condensation, and catalytic hydrogenation. The last step yields a mixture of cis and trans diastereoisomers which can be separated by column chromatography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
On the Mechanism of the Puzzling “Endocyclic” Skeletal Rearrangement of 1,6‐Enynes
Authors: Cabello Noemí , Jiménez‐Núñez Eloísa , Buñuel Elena , Cárdenas Diego J. , Echavarren Antonio M. 
Published: July 2007

AbstractSkeletal rearrangements of simple 1,6‐enynes have been studied in order to determine the factors that control the formation of five‐ or six‐membered rings. Simple 1,6‐enynes substituted only at C‐4 preferentially give six‐membered rings on skeletal rearrangement in the presence of gold(I) catalysts, whereas increasing electron‐withdrawing character of substituents at C‐4 leads to five‐membered rings. Reactions of these simple enynes in the presence of PtCl4 as catalyst give exclusively exo‐double skeletal rearrangements. Enynes substituted at the alkyne also react with AuI catalysts to give exclusively products of exo‐double rearrangement. The different mechanisms have been analyzed by DFT calculations. Although a pathway for the formation of six‐membered rings involving two steps in a ring‐expansion/ring‐contraction process was found, the activation energy of the first step is too high. Instead, this skeletal rearrangement appears to follow an exo‐single skeletal rearrangement in which the initial cyclopropyl gold carbene opens to form a six‐membered ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Highly Selective Hydroformylation of Vinylarenes to Branched Aldehydes by [Rh(cod)Cl]2 Entrapped in Ionic Liquid Modified Silica Sol‐Gel
Authors: Hamza Khalil , Blum Jochanan 
Published: July 2007

AbstractA co‐entrapped mixture of [Rh(cod)Cl]2 and Na[Ph2P‐3‐(C6H4SO3)] within a silica sol‐gel matrix modified with ca. 5 % of 1‐butyl‐3‐[3‐(trimethoxysilyl)propyl]imidazolium chloride catalyzes, in n‐heptane, the hydroformylation of a variety of vinylarenes. At 50 °C and under 6.9 bar each of H2 and CO the reaction is high‐yielding and highly selective. Non‐hindered substrates give >95 % of branched aldehydes and only <5 % of the linear isomers. The ceramic catalyst isleach‐proof and recyclable. It does not lose its high catalytic activity and selectivity for at least four runs. The selectivity depends on the pressure of the gases, the temperature and the solvent. The electronic nature has no influence on the selectivity, but the latter is diminished by steric effects. Upon omission of the sol‐gel component, the catalyst deteriorates and practically loses its activity after the first half‐life of the reaction. In the absence of the ionic liquid, the catalyst undergoes substantial leaching.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)