IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 121 , Issue 10
Showing 1-15 articles out of 15 articles from the selected issue
  • Seiichi Shin, Takuji Nakazato
    2001 Volume 121 Issue 10 Pages 1011-1016
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Katsumi Tsubota, So Noguchi, Hideo Yamashita
    2001 Volume 121 Issue 10 Pages 1017-1023
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, the convergency of the multigrid method for electromagnetic field computations is presented. The convergency and computational time of three multigrid algorithms (V-cycle, W-cycle and Full multigrid) are discussed and compared with each other. A comparison of the computational time between the multigrid method and the ICCG method, which is commonly used solution method in the finite element analysis, is also presented. It is proven that the convergency of the multigrid methods is better than that of the ICCG method especially for solving the large system.
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  • Tung-Hai Chin, Motomu Nakano, Guang Zeng
    2001 Volume 121 Issue 10 Pages 1024-1031
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Novel approach for operation analysis of vector control synchronous machine has been described. To draw the vector diagram under adjustable speed operation, the concept of normalized voltage has been introduced. It is to divide the voltage value by angular frequency of the machine, then the voltage vectors, which contain angular frequency immanently, will not change their length under adjustable speed operation, and the vector diagram will keep its size unchanged for the whole speed range. Also, reactance drop locus and its accompanying yardstick circle for determining current phase angle, in corresponding to the variation of the given armature current vector, were deduced. Then, the operation of the machine for the whole adjustable speed range can be represented in single diagram. As the accompanying matters, the methods for calculating the operating characteristics of maximum torque control and 100% power factor control were shown.
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  • Shinji Shinnaka
    2001 Volume 121 Issue 10 Pages 1032-1040
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper proposes a new position-sensorless position control method for high-speed spindle drive systems. Mechanical vulnerability of position-sensors such as encoder mounted on spindle motor is becoming a serious problem as required speed increases. For high-speed more than 1, 500 (rad/s), sensorless drive is preferred. It is possible for current technologies to control spindle motor in speed control mode without the sensor, but not in position control mode without the sensor. In example of high-speed spindle systems of automatic machine tools, implements must be automatically attached on and removed off the spindle at a standstill. The automation means necessity of position control, for which current technologies require the sensor. The proposed method makes it possible to realize pure-sensorless high-speed spindle systems performing in both speed and position control modes. The method can attain position control performance of quick settlement from speed control and repetitive positioning-precision of 0.006 (rad), 0.4 (degree), which is similar to one by current sensor-used methods.
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  • Takaharu Takeshita, Yasunobu Toyoda, Nobuyuki Matsui
    2001 Volume 121 Issue 10 Pages 1041-1048
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper presents a dc voltage control scheme of a single-phase PFC converter which can realize both the harmonic suppression of the input current and the fast dynamic response of the dc voltage. Instead of the constant dc voltage reference, the controller calculates the fluctuating dc voltage reference having the frequency twice a source frequency. In the calculation of the dc voltage reference, the circuit parameters are used. Since the parameter errors may cause the error in the dc voltage reference, the parameter identification is also described. The effectiveness of the proposed control algorithm has been verified by experiments.
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  • Toshiaki MURAI, Hitoshi HASEGAWA
    2001 Volume 121 Issue 10 Pages 1049-1054
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A new type of magnetic levitation system called the Inductrack, has been proposed by R F. Post. This system is composed of a special arrangement of permanent magnets on board which is called the Halbach array, and a close-packed array of shorted coils in the longitudinal direction on the ground. This composition can obtain a large magnetic force, a very low take-off speed and a high lift-to-drag ratio. This paper describes numerical simulations of the Inductrack magnetic levitation by the Fourier series analysis which is utilized in the analysis of superconducting magnetic levitation. By using numerical examples considering a full-scale car model, we reveal the features of the Inductrack system in comparison with the superconducting magnetic levitation.
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  • Norihiko SAGA, Taro NAKAMURA, Masaru NAKAZAWA
    2001 Volume 121 Issue 10 Pages 1055-1060
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Electro-rheological (ER) fluid is a member of the family of intelligent fluids, and it has the character that the apparent viscosity can be controlled according to strength of an applied electric field. Various applications using ER fluid have been developed. Recently, the research on whether ER fluid can be applied to the area of the motion control of robotics has been performed.
    For example, we see that robots in factory applications have two links. For the sake of safety, it is necessary to create an enclosure around the robot, since it is not possible for humans to approach large-capacity robots. Thus, we considered that the robot arm would not injure a human if it was possible for the robot arm to bend softly when making human contact, with the force applied at the arm tip skillfully controlled at the joint. In order to realize this motion, we will develop an actuator build into the joint, and we examined the control
    method (impedance control) of the robot arm.
    In this paper, we developed a one-shaft type ER clutch to be installed at the joint division of a robot arm. The developed ER clutch is stronger than the conventional ER clutch in terms of radial motion.
    Further, we examined the fundamental characteristics of the developed ER clutch in order to apply impedance control to it. The results of our experiment show that the coefficient of viscosity is directly proportional to the applied electrical field. Therefore, it is concluded that the clutch is able to be controlled by impedance control.
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  • Toru Namerikawa, Masayuki Fujita
    2001 Volume 121 Issue 10 Pages 1061-1067
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper deals with uncertain model structures, model validation and robust performance analysis of active magnetic bearings. The dynamics of active magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets. The feedback control is indispensable to stabilize the system, further the closed-loop systems of magnetic bearings should have robustness for stability and performance against model uncertainties. First we derive a nominal mathematical model of AMBs as a linear state-space model under some assumption and idealization, then we consider the discrepancy between the real physical systems and the obtained nominal design model. This discrepancy can be expressed as the structured uncertainties by Linear Fractional Transformation. These uncertainties include linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition. Finally, we validate the interconnection structure with the nominal model and uncertainties, and analyze the robustness of stability and performance of the closed-loop system via the mixed structured singular value.
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  • Yukio Odawara
    2001 Volume 121 Issue 10 Pages 1068-1074
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    To supply power to a rotating detector without contact, we propose a core-type rotary transformer which consists of a circular coil and excitation coils. The circular coil is attached to a rotating shaft with a detector. And each excitation coil is linked to the circular coil by a core. The advantage of this system is that supply power and efficiency can easily increase by linking multiple excitation coils in parallel to a circular coil. In addition to this, the size of a circular coil can be easily changed, and the accuracy of assembling is not severe.
    In this paper, characteristics of the core-type rotary transformer and calculations of its inductance are described by 3 dimensional magnetic analysis based on FEM. The features of this driving circuit and its performance obtained from differential equations are also shown. And these were experimentally confirmed.
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  • Satoshi Ogasawara, Masato Fujikawa, Hirofumi Akagi
    2001 Volume 121 Issue 10 Pages 1075-1082
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper proposes a new PWM rectifier/inverter system that is capable of suppressing not only supply harmonic currents but also electromagnetic interference (EMI). The conversion system consists of a PWM rectifier and inverter, and an active common-noise canceler (ACC) which has been proposed by the authors. The ACC developed for this system is characterized by sophisticated connection of a common-mode transformer which can compensate for common-mode voltages produced by both the PWM rectifier and inverter. As a result, the size of the common-mode transformer can be reduced to 1/3, compared with the previously proposed ACC. A prototype PWM rectifier/inverter system (2.2kW) has been implemented and tested. Some experimental results show reduction characteristics of the supply harmonic current and EMI.
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  • Akira Tozune, Toru Takeuchi, Masahiro Saito
    2001 Volume 121 Issue 10 Pages 1083-1088
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Tapped-winding capacitor motor is widely used to drive a shaft-mounted fan. In this motor the burnout accident of phaseshifting capacitor sometimes happens. The cause of this accident is considered to be the transient capacitor current. In this paper, equations Sir calculating transient characteristic are derived in 3 types of tapped-winding capacitor motors. Based on these equations, transient characteristics are clarified in high-speed winding connection and low-speed winding connection. Further, from the designing viewpoint, effects of turns ratio and capacitance of capacitor on the transient characteristics are examined and the procedure for choosing winding ratio and capacity is suggested. The transient current is shown to decrease by about 40% by this method.
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  • Makoto Saitou, Tosihisa Shimizu
    2001 Volume 121 Issue 10 Pages 1089-1090
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In order to control the power factor on a single-phase grid connectable inverter, a novel control method with Hilbert transformer is presented in this paper. Using Hilbert transformer theory, the d-q transformation on singlephase utility line current and utility voltage can be realized, and active power and reactive power can be controlled separately without offset. The effectiveness of the proposed control method is verified by the computer simulator, and some significant characteristics are also shown in this paper.
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  • Hiroyuki Ogiwara, Mutsuo Nakaoka
    2001 Volume 121 Issue 10 Pages 1091-1092
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    We have reported a ZCS high frequency inverter for induction heating uses elsewhere. Its load circuit is composed of a parallel tuned tank load circuit having a heating coil with relatively small inductance, leading to limited applications for the inverter. This paper presents a duplicated tuned load circuit to deal with a tank load having a heating coil with a higher inductance, to widen application range of the inverter. It is found that the high frequency inverter having the improved tank load circuit reveals a high efficiency reaching 89 percent. Its circuit operation and performance are analyzed on the basis of computer-aided simulation and its actual behaviors are examined from a practical point of view for a feasible breadboard.
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  • Takeshi Miura, Toshiyuki Taniguchi
    2001 Volume 121 Issue 10 Pages 1093-1094
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this work, the authors suggest the method for damping of natural oscillation of a stepping motor, which only requires adjustment of switching sequence. The robustness against variation of the load inertia is taken into consideration in this method. The switching sequence is constructed being based on the waveform which do not contain the frequency component in the region where the natural frequency of the motor, varies with change of load inertia, can be exist. Pulse width modulation is used to transform the waveform to the switching sequence. The effectiveness of this method is confirmed by the experiment.
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  • Kenmei Kukihara
    2001 Volume 121 Issue 10 Pages 1095-1096
    Published: October 01, 2001
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A new class of thyristor action is proposed for switching off currents with very small off-gate current. The new units exceed conventional GTO thyristors by _??_100times in off-gate gain. The unit consists of a main pnp-transistor, a control npn-transistor, a diode and a resistor. The two transistors form conventional thyristor equivalently. The control transistor has a bypass diode between its base resistor and emitter, to make base current very small in order to be absorbed with small off-gate current. The bypass diode puts away the restraint on amplitude factors of inner transistors, in contrast to conventional GTOs. The base resistor, deciding bypass ratio, frees transistor from deeply saturated states and realizes high speed actions. And also, the base resistor restricts inflow into off-gate from main current.
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