IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 129, Issue 11
Displaying 1-28 of 28 articles from this issue
Special Issue on “Technologies of Rotating Machinery”
Preface
Special Issue Paper
  • Wataru Kitagawa, Yosuke Hattori, Koji Fujiwara, Yoshiyuki Ishihara, To ...
    2009 Volume 129 Issue 11 Pages 1016-1021
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    This paper describes the preliminary investigation of the database of magnetic properties of magnetic materials to realize the highly accurate magnetic field analysis. By showing the various measured properties, the contents of database, which are possible to be prepared by means of current measurement techniques, were shown.
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  • Katsumi Yamazaki, Yuji Kanou, Yu Fukushima, Shunji Ohki, Akira Nezu, T ...
    2009 Volume 129 Issue 11 Pages 1022-1029
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    In this paper, we present the development of interior magnet motors with concentrated windings, which reduce the eddy current loss of the magnets. First, the mechanism of the magnet eddy current loss generation is investigated by a simple linear magnetic circuit. Due to the consideration, an automatic optimization method using an adaptive finite element method is carried out to determine the stator and rotor shapes, which decrease the eddy current loss of the magnet. The determined stator and rotor are manufactured in order to proof the effectiveness by the measurement.
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  • Makoto Takanezawa, Masami Mori, Takahiro Ueno, Noboru Morita, Toru Ota ...
    2009 Volume 129 Issue 11 Pages 1030-1037
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    In the case of high speed and large capacity AC machines, such as turbine generators and large synchronous motors for industrial use, steel collector rings are generally applied to the brush/ring operation, where higher reliabilities are required, especially for large machines when compared to small machines. The brush/ring operation failures directly cause the service operation to shut down. Although steel ring application to those machines has been successful for almost sixty years, at present no one knows why “steel” is applied to the collector ring. It is considered that steel ring application technologies have never been disclosed or studied. In this study, the following points are investigated.
    1) Consistency analysis for steel ring application
    2) Experimental analysis for brush spark and collector ring hazard
    3) Experimental analysis for brush contact V-I characteristics
    The above-mentioned points help in improving the reliabilities of the brush/collector ring operation, where the results of steel ring are completely compared with these of copper ring.
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  • Hajime Ichita, Rion Takahashi, Toshiaki Murata, Junji Tamura, Mamoru K ...
    2009 Volume 129 Issue 11 Pages 1038-1047
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    In recent years, many wind turbine generation systems (WTGSs) have been installed in many countries from the viewpoint of global warming, for example, for reducing CO2 emissions. However the wind turbine generator output basically fluctuates due to wind speed variations. Therefore, the annual energy production depends on the wind speed characteristic of each area. This paper presents a method to calculate the loss, power, and efficiency of WTGS with doubly fed synchronous generator (DFSG), in which the wind speed characteristic is expressed by a weibull distribution function. The annual energy production and capacity factor of the wind farm can also be obtained by the proposed method. The coefficients of weibull distribution function given by local area wind energy prediction system (LAWEPS), NEDO, have been used in the analyses of this study.
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  • Takahiro Mizuguchi, Kenji Nakamura, Takayuki Koyama, Osamu Ichinokura
    2009 Volume 129 Issue 11 Pages 1048-1053
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    Soft magnetic composites (SMCs) have the following advantages: three-dimensional magnetic isotropy, high resistivity, and recyclability. By using SMC, therefore, a new concept motor with a three-dimensional structure can be developed. Its power-to-space ratio and efficiency can be improved since the space factor of winding and the space utilization factor of the motor is increased. This paper describes a design method of a claw teeth motor made of SMC by reluctance network analysis (RNA)-based experimental design. First, a three-dimensional RNA model of the claw teeth motor is presented. Next, the RNA-based experimental design of the claw teeth motor is presented. As a result, the average torque is improved by approximately 50%. In addition, the calculation time required for the design is significantly reduced by the proposed design method.
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  • —Sastainable Voltage of DC Arc—
    Yuji Nakanishi, Kensho Sugimoto, Noboru Morita
    2009 Volume 129 Issue 11 Pages 1054-1059
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    Although in recent years, large DC machines have gradually been replaced with variable-speed AC machines, many large DC machines are still operating in steel mills. Flashover is still a frequent occurrence and has been ongoing issues since DC machines were first brought into use. In this investigation, flashover experiments were performed using model tests. The sustained voltage of the DC arc was cleared and copper dragging was found to be related to flashover.
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  • Masatsugu Nakano, Chiyo Fujino, Yoshihiro Tani, Akihiro Daikoku, Yukar ...
    2009 Volume 129 Issue 11 Pages 1060-1067
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    The magnetic characteristic of magnetic steel sheets that are used for stator core of motors changes with stress. This change of magnetic characteristic affects the characteristic of the motors. For example, iron loss increases because of stress that acts on the stator core inserted in a frame by shrink fit. In this paper, the authors focus on iron loss calculation. Calculation methods by considering stress distribution are proposed in order to carry out coupled stress and electromagnetic field analysis. The proposed methods are as follows: (1) considering von-Mises stress, (2) considering scalar value of principal stress, and (3) considering both principal stress and direction of magnetic flux density. The calculated results are compared with an examination result of the prototype PM motor in order to verify the validity of the methods. As a result, the method that considers principal stress and direction of magnetic flux density is the most precise among the three ones.
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  • —Comparison between Results Separated by Experiment and Field Analysis—
    Katsumi Yamazaki, Noriaki Fukushima
    2009 Volume 129 Issue 11 Pages 1068-1074
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    In this study, we investigate the carrier loss of induction motors driven by PWM inverters from the results of both the experiment and the electromagnetic field analysis. In the experiment, the motor is driven by the PWM inverter as well as a sinusoidal power supply. The carrier loss is obtained from the increase in the losses. The electromagnetic field analysis is carried out by considering the skin effect of the electrical steel sheet applied to the core. The measured and calculated results are found to be in good agreement. It is clarified that the main component of the carrier loss is the harmonic core losses and that consideration of the skin effect in the core is indispensable to the accurate calculation of the carrier loss.
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  • Isao Hirotsuka, Kazuo Tsuboi
    2009 Volume 129 Issue 11 Pages 1075-1084
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    The capacitor motor (CRM) is widely used to drive industrial equipments and electric home appliances. Recently, the reduction in the vibration and noise of the CRM has become increasingly important from the standpoint of environmental improvement. However, the electromagnetic vibration of the CRM under load has not been analyzed sufficiently. Therefore, we have studied the electromagnetic vibration of CRM for the purpose of reducing it. In a previous paper, the relationships for a backward magnetic field, the equivalent circuit current, and the vibration of the CRM were clarified. The present paper theoretically and experimentally discusses the effect of the slot combination and skewed slot on the electromagnetic vibration of CRM under load. The primary conclusions are as follows:
    (1) In the case of 4-pole and 6-pole CRMs, the dominant electromagnetic vibration of CRMs was theoretically attributed to three types of electromagnetic force waves. Two types of electromagnetic force waves are generated: one wave is generated by the interaction of two forward magnetic fluxes, such as those of a three-phase squirrel-cage induction motor, and the other wave is generated under the influence of a backward magnetic flux.
    (2) The characteristics of dominant electromagnetic vibration depending on load and running capacitor were classified theoretically and experimentally into three types based on the characteristics of the electromagnetic force wave and equivalent circuit current.
    (3) The influences of magnetic saturation in dominant electromagnetic vibration were verified experimentally and their causes were clarified theoretically in relation to electromagnetic force waves.
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  • Junichi Asama, Akira Chiba, Tadashi Fukao
    2009 Volume 129 Issue 11 Pages 1085-1091
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    A thrust magnetic bearing using a magnetic disk with a large diameter is usually employed in five-degrees-of-freedom controlled magnetic bearings and bearingless drive systems. However, the large disk may result in a complicated assembly process and increased peripheral velocity, which results in the limitation of a maximum rotational speed. In this paper, a novel thrust magnetic bearing using a cylindrical permanent magnet (PM) mover without the large disk has been proposed, designed, and tested. Coreless coil stators are employed for the reduction of radial attractive force that may cause disturbance to the bearingless drive system. To enhance the thrust force, iron disks with the same diameter of the PM mover are attached to the rotor. The fabricated actuator can generate a desired thrust force with less disturbance to the bearingless motor.
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Paper
  • Jafar Adabi, Firuz Zare
    2009 Volume 129 Issue 11 Pages 1092-1100
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    This paper presents the analysis of shaft voltage in different configurations of a doubly fed induction generator (DFIG) and an induction generator (IG) with a back-to-back inverter in wind turbine applications. Detailed high frequency model of the proposed systems have been developed based on existing capacitive couplings in IG & DFIG structures and common mode voltage sources. In this research work, several arrangements of DFIG based wind energy conversion systems (WES) are investigated in case of shaft voltage calculation and its mitigation techniques. Placements of an LC line filter in different locations and its effects on shaft voltage elimination are studied via Mathematical analysis and simulations. A pulse width modulation (PWM) technique and a back-to-back inverter with a bidirectional buck converter have been presented to eliminate the shaft voltage in a DFIG wind turbine.
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  • Hiroyoshi Asaumi, Hiroshi Fujimoto
    2009 Volume 129 Issue 11 Pages 1101-1108
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    Ball screw driven stages are used for industrial equipments such as machine tools and semiconductor equipments. Fast and precise positioning is necessary to enhance productivity and microfabrication technology of the system. The rolling friction of the ball screw driven stage deteriorate the positioning performance. Therefore, the control system based on the friction model is necessary. In this paper, we propose variable natural length spring model (VNLS model) as the friction model. VNLS model is simple and easy to implement as friction controller. Next, we propose multi variable natural length spring model (MVNLS model) as the friction model. MVNLS model can represent friction characteristic of the stage precisely. Moreover, the control system based on MVNLS model and disturbance observer is proposed. Finally, the simulation results and experimental results show the advantages of the proposed method.
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  • Yukinori Inoue, Shigeo Morimoto, Masayuki Sanada
    2009 Volume 129 Issue 11 Pages 1109-1117
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    This paper proposes a variable speed wind generation system using a direct torque controlled interior permanent magnet synchronous generator. The proposed system has no wind speed and generator position sensors, and thus, it is considered that the proposed system has cost and reliability advantages. The proposed direct torque control (DTC) system in wind power generation has several advantages over conventional current control. First, DTC is well suited for the maximum power point tracking (MPPT) control that is implemented by controlling the generator torque. Second, the method of flux-weakening to maintain the terminal voltage at the limiting value of the converter is simple. Finally, a novel method is proposed for torque limiting, which makes it easy to maintain the armature current at the limiting value. The proposed method accomplishes current limiting using the reactive torque, which is calculated as the inner product of the flux and current. This does not require generator parameters such as magnet flux and inductances. Experimental results demonstrate the effectiveness of the proposed system using a wind turbine emulator instead of the actual wind turbine.
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  • Mahmoud A. Sayed, Takaharu Takeshita
    2009 Volume 129 Issue 11 Pages 1118-1125
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    This paper presents a new method for achieving line loss minimization and voltage regulation in the loop distribution systems, simultaneously. First, mathematical analysis of the line loss minimum conditions in the loop distribution systems is presented. Then, load voltage regulation is applied in the loop distribution system under line loss minimum condition. Reference angle of the desired load voltage is the main factor that can be used to minimize total line loss during load voltage control. In order to achieve these two objectives simultaneously, the UPFC (unified power flow controller), a typical FACTS (flexible AC transmission systems) device, that is capable of instantaneous control of transmission and distribution power flow, is used. Also, the UPFC control scheme to regulate the load voltage under line loss minimization is presented. The effectiveness of the proposed control scheme has been verified experimentally using laboratory prototype in a 200V, 6kVA system.
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  • Hirokazu Matsumoto
    2009 Volume 129 Issue 11 Pages 1126-1132
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    The supply used in servo systems tends to have a high voltage in order to reduce loss and improve the response of motor drives. We propose a new boost motor driver that comprises EDLCs. The proposed driver has a simple structure, wherein the EDLCs are connected in series to the supply, and comprises a charge circuit to charge the EDLCs. The proposed driver has three advantages over conventional boost drivers. The first advantage is that the driver can easily attain the stable boost voltage. The second advantage is that the driver can reduce input power peaks. In a servo system, the input power peaks become greater than the rated power in order to accelerate the motor rapidly. This implies that the equipments that supply power to servo systems must have sufficient power capacity to satisfy the power peaks. The proposed driver can suppress the increase of the power capacity of supply facilities. The third advantage is that the driver can store almost all of the regenerative energy. Conventional drivers have a braking resistor to suppress the increase in the DC link voltage. This causes a considerable reduction in the efficiency. The proposed driver is more efficient than conventional drivers. In this study, the experimental results confirmed the effectiveness of the proposed driver and showed that the drive performance of the proposed driver is the same as that of a conventional driver. Furthermore, it was confirmed that the results of the simulation of a model of the EDLC module, whose capacitance is dependent on the frequency, correspond well with the experimental results.
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Letter
  • Junichi Tsuchiya
    2009 Volume 129 Issue 11 Pages 1133-1134
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    Several types of surface motors (SFMs), which have the ability to perform surface motion, have been proposed. We have proposed a new type of SFM using Halbach-type permanent magnet that does not require wires to be connected to the mover. The feature of this new type of SFM is that the mover can perform rotation in addition to linear motion on a plane surface. In this letter, the structure, the movement principle, and the characteristics of the proposed SFM using Halbach-type permanent magnet are investigated.
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  • Ryozo Itoh, Kouichi Ishizaka
    2009 Volume 129 Issue 11 Pages 1135-1136
    Published: November 01, 2009
    Released on J-STAGE: November 01, 2009
    JOURNAL FREE ACCESS
    Improvement in the input current distortion of single-phase rectifier operating under the current-mode control with a turn-on at constant clock time is studied by simulation. Advantage of this rectifier is its ability to be realized by using only one active power device. To reduce a difference between the input current and its reference immediately after a zero-crossing, the reversed snubber capacitor voltage is superimposed on the supply by the resonant snubber switch cell including an active power device. The simulated results confirm that the input current distortion can be improved and so the total harmonic distortion becomes smaller.
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