IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 131 , Issue 9
Showing 1-28 articles out of 28 articles from the selected issue
Paper
  • Dimas Anton Asfani, Syafaruddin, Mauridhi Heri Purnomo, Takashi Hiyam ...
    2011 Volume 131 Issue 9 Pages 1093-1102
    Published: September 01, 2011
    Released: September 01, 2011
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    Faults in induction motor winding can be successfully detected using different motor current signature analysis. However, there still remain some parts where the performance of conventional methods can be improved. In case of the fast Fourier transform (FFT) method, it can only identify the permanent fault, but not the temporary one because the method gives frequency content similar to the normal condition. Moreover, the FFT technique is unable to provide the exact timing information of the fault occurrence. On the other hand, the method based on the first level wavelet transform sometimes gives misleading information, especially in case of starting and ending points of temporary short circuit. For these reasons, this paper comes up with a new method for winding fault detection, which analyzes motor current spectrogram based on extension wavelet analysis, called the second level Haar wavelet transform. The proposed method is able to detect temporary fault with very short duration and low current level with more clear information than that of the first level. Several testing scenarios are presented to confirm the robustness of the proposed method including the provision of time of occurrence information for each case.
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  • Kenji Takahashi, Kiyoshi Ohishi, Tosiyuki Kanmachi
    2011 Volume 131 Issue 9 Pages 1103-1111
    Published: September 01, 2011
    Released: September 01, 2011
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    In this paper, a new driving method is proposed for interior permanent magnet synchronous motor (IPMSM) in which d-axis voltage is given priority. When an anti-windup PI current controller that considers q-axis voltage saturation is applied to the IPMSM servo system, the IPMSM servo system prevents the oscillatory q-axis current response. However, in the case of this IPMSM servo system, the d-axis current oscillates because of the voltage saturation. The proposed driving method gives priority to the d-axis voltage in order to avoid the d-axis voltage saturation and prevents the oscillatory d-axis current response. Therefore, the IPMSM servo system can achieve stable responses of both d and q axis currents by using the proposed driving method. Moreover, the proposed driving method is improved to operate in the entire over-modulation region. Because the proposed driving method can increase the fundamental component of inverter output voltage, the IPMSM servo system achieves the quick torque and speed responses despite voltage saturation. The experimental results verify the effectiveness of the proposed servo system.
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  • Kazuto Sakai, Satoru Kuramochi
    2011 Volume 131 Issue 9 Pages 1112-1119
    Published: September 01, 2011
    Released: September 01, 2011
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    Reduction in the power consumed by motors is important for energy saving in the case of electrical appliances and electric vehicles (EVs). The motors used for operating these devices operate at variable speeds. Further, the motors operate with a small load in the stationary mode and a large load in the starting mode. A permanent magnet motor can be operated at the rated power with a high efficiency. However, the efficiency is low at a small load or at a high speed because the large constant magnetic force results in substantial core loss. Furthermore, the flux-weakening current that decreases the voltage at a high speed leads to significant copper loss and core loss. Therefore, we have developed a new technique for controlling the magnetic force of a permanent magnet on the basis of the load or speed of the motor. In this paper, we propose a novel motor that can vary the magnetic flux of a permanent magnet and clarify the principle and basic characteristics of the motor. The new motor has a permanent magnet that is magnetized by the magnetizing coil of the stator. The analysis results show that the magnetic flux linkage of the motor can be changed from 37% to 100% that a high torque can be produced.
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  • Noriya Nakao, Kan Akatsu
    2011 Volume 131 Issue 9 Pages 1120-1127
    Published: September 01, 2011
    Released: September 01, 2011
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    This study presents a new method for torque ripple control in permanent magnet synchronous motors (PMSMs). The proposed method is based on instantaneous torque estimation with a mathematical model. The model provides a new expression for the torque and requires a small amount of off-line data and the values of some machine parameters. With the new mathematical model, torque ripple control is possible at low cost with existing platforms. In the proposed method, the torque ripple is suppressed by feedforward (FF) control and feedback (FB) control. The FF control can compensate for drawbacks in the FB control based on the new model. Therefore, the proposed method for torque ripple control is effective under various conditions. In this paper, the proposed method is evaluated by performing both simulations and experiments.
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  • Ryosuke Hanyu, Toshiaki Tsuji
    2011 Volume 131 Issue 9 Pages 1128-1134
    Published: September 01, 2011
    Released: September 01, 2011
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    This paper proposes a whole-body haptic sensing system that has multiple supporting points between the body frame and the end-effector. The system consists of an end-effector and multiple force sensors. Using this mechanism, the position of a contact force on the surface can be calculated without any sensor array. A haptic sensing system with a single supporting point structure has previously been developed by the present authors. However, the system has drawbacks such as low stiffness and low strength. Therefore, in this study, a mechanism with multiple supporting points was proposed and its performance was verified. In this paper, the basic concept of the mechanism is first introduced. Next, an evaluation of the proposed method, performed by conducting some experiments, is presented.
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  • Yoshihide Igari, Toshiyuki Murakami
    2011 Volume 131 Issue 9 Pages 1135-1140
    Published: September 01, 2011
    Released: September 01, 2011
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    With the increase in the number of drivers, traffic accidents have increased in number. The process of driving includes acknowledgment, judgment, and operation. Among these, acknowledgment is the most important because mistakes in acknowledgment accounts for 70% of the human factors causing accidents. This paper proposes the cooperation between a haptic pedal system and the driver, which gives the driver information about the road condition. It is confirmed that the proposed method helps in accurate acquisition of road condition information and transmission of this information to drivers; then, the driver's response is analyzed to check whether the information transmission is efficient and the support provided to the driver is adequate. Simulation and experiments were carried out to verify the validity of the proposed approach.
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  • Yoshio Tomigashi, Kenji Ueyama
    2011 Volume 131 Issue 9 Pages 1141-1148
    Published: September 01, 2011
    Released: September 01, 2011
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    A method for directly estimating the axis corresponding to the current phase in maximum torque per ampere (MTPA) control is proposed for sensorless vector control. This axis is called the maximum torque control (MTC) axis. In past studies concerning such methods, the behavior of the axis has been considered only for the case of MTPA control and not for an arbitrary current vector (with flux weakening control) that has a phase different from that for MTPA control. This paper enhances the definition of the MTC axis for an arbitrary current vector, describes an extended EMF model based on the MTC axis, and presents a method that can directly estimate the axis for an arbitrary current vector with flux weakening control. The effectiveness of the proposed method is confirmed by numerical analysis results.
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  • Masahiko Tsukakoshi, Kouki Matsuse
    2011 Volume 131 Issue 9 Pages 1149-1156
    Published: September 01, 2011
    Released: September 01, 2011
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    This paper presents the phase control characteristics for the vector control of a wound-field synchronous motor at a fixed modulation ratio. In the general vector control method, current control is based on two-axis or three-axis control by estimation of the flux direction. In this case, the amplitude of the current control result is generally neglected. However, because several current controllers are work independently, the synthetic amplitude of the voltage must be less than the maximum value of the inverter voltage. This amplitude of the inverter voltage is due to the error in flux estimation. This implies that the utilization efficiency based on inverter voltage modulation reduces. In this paper, the method of phase control using fixed modulation ratio is proposed. With this method, the rating voltage of the inverter and the margin can be easily set. The phase control method assumes a fixed modulation ratio, and hence, it is more efficient than the conventional M-T axis method, which involves current control. Continuous crossover gain change is applied to this control in order to combine the conventional M-T axis current control and the proposed phase control. The characteristics of this control are confirmed by experimental results.
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  • —Smooth Transition from Four-wheels Mode to Wheeled-inverted-pendulum Mode by Initial Value Compensation during Motion—
    Noriaki Hirose, Kazutoshi Sukigara, Hideki Kajima, Masaaki Yamaoka
    2011 Volume 131 Issue 9 Pages 1157-1164
    Published: September 01, 2011
    Released: September 01, 2011
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    The present paper introduces a novel standing-up control strategy based on Initial Value Compensation (IVC) for a Personal Mobility Robot (PMR). PMRs, which are wheeled-inverted-pendulum-type mobility-assist devices, offer the following advantages: (1) they can turn at a point; (2) they can maintain a level seating posture on a slope; and (3) they have a smaller footprint than conventional electric wheelchairs with four wheels. On the other hand, the user must maintain the posture of the PMR by using additional assist wheels on the ground when mounting/dismounting the PMR and working while seated on the PMR. In order to satisfy these requirements, we propose the following approach. First, the PMR accelerates to lift its assist wheels off the ground and determines whether the assist wheels are in contact with the ground. The feedback controller is then switched to wheeled-inverted-pendulum mode using the proposed IVC. The proposed IVC is designed such that the transient responses are improved and the amplitude of the control input and the jerk component are suppressed, in order to reduce the shock felt by the driver. The effectiveness of the proposed approach has been verified by conducting numerical simulations and experiments using a prototype PMR.
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  • Yoshimoto Takamichi, Katsuhiro Hirata, Yasuyoshi Asai, Kenji Ueyama, E ...
    2011 Volume 131 Issue 9 Pages 1165-1170
    Published: September 01, 2011
    Released: September 01, 2011
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    Recently, linear oscillatory actuators have been used in a wide range of applications. In particular, small linear oscillatory actuators are expected to be applied to haptic devices by extension to multi-degree-of-freedom motion with an arbitrary acceleration.
    In this paper, we propose a compact two-DOF oscillatory actuator that can move in various directions on the plane. The static and dynamic characteristics of the actuator are determined by the 3-D finite element method. The effectiveness of this method is shown through a comparison of the obtained results with the experimental results of a prototype.
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Letter
  • Masayoshi Yamamoto, Hirotaka Toda, Takahiro Kawashima, Toshiyuki Yoshi ...
    2011 Volume 131 Issue 9 Pages 1171-1172
    Published: September 01, 2011
    Released: September 01, 2011
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    The conventional recovery-less boost type converter cannot achieve the soft switching operation in case of the turn off transition. In this paper, the novel hybrid recovery-less boost type converter, which can achieve the soft switching turn off transition, is proposed. Furthermore, the proposed hybrid recovery-less boost type converter has the switch function between the conventional recovery-less mode and the proposed soft switching mode. In general, the efficiency in the soft switching converter is less than the hard switching in case of the lower output power condition. However, using the switch function of the proposed boost type converter, the hybrid recovery-less boost type converter can achieve the high efficiency performance in the whole output power area in spite of the soft switching operation. The proposed hybrid recovery-less boost type converter is evaluated and discussed from experimental point of view.
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  • Inami Asai, Takaharu Takeshita
    2011 Volume 131 Issue 9 Pages 1173-1174
    Published: September 01, 2011
    Released: September 01, 2011
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    This paper presents the simple derivation process of duty cycles of a three-phase to three-phase matrix converter. The duty cycles with only four times commutations for all three phases during one control period are derived from the input voltages and the references of the output voltages and input power factor angle.
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