IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 133 , Issue 12
Showing 1-29 articles out of 29 articles from the selected issue
Paper
  • Takanori Isobe, Kyohei Kato, Naoto Kojima, Ryuichi Shimada
    2013 Volume 133 Issue 12 Pages 1104-1111
    Published: December 01, 2013
    Released: December 01, 2013
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    With an increase in renewable energy source installations in the domestic field, bidirectional ac/dc converters are attracting attention. Efficiency, power density improvement and EMI reduction are necessary for converters in this field. Using high-frequency switching can reduce the size of passive components and help achieve a high-power-density converter; however, the switching losses and EMI can increase. In this study, we propose a new bidirectional ac/dc converter circuit topology that can reduce the switching losses and EMI with a soft-switching operation. The soft-switching operation is based on the DCM (discontinuous current mode) operation and a MERS (magnetic energy recovery switch)-type turn-off snubber. This paper focuses on a modulation technique applied to this converter. Experiments with a fabricated 1kW converter were conducted, and the principles of operation were confirmed. Loss analysis indicates that inductor design is the key design issue for the proposed converter.
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  • Kazuhiro Tsujino, Cunwei Lu
    2013 Volume 133 Issue 12 Pages 1112-1119
    Published: December 01, 2013
    Released: December 01, 2013
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    The reuse of recycled auto parts can lower the production costs and the amount of exhaust CO2. This conservation technique has attracted interest in recent years. Before reused auto parts are released into the market, their quality must be checked by inspecting them for cracks and dents. However, since many auto parts exhibit strong specular reflection, applying a technique such as image measurement is difficult. Therefore, inspection is now conducted by engineers through manual observation.
    In this paper, we propose an automatic detection technique for dents in reusable auto parts. Since a dent is a form change, we detect it by using a three-dimensional image measurement technique. To overcome the problems associated with the specular reflection exhibited by auto parts, we propose a method of combining the indirect pattern projection measurement technique and the phase-shifting analysis technique. Furthermore, we propose a dent detection technique based on the multiplex phase-shifting image to improve the accuracy of dent analysis. Finally, some experimental results are shown.
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  • Kazuya Hirata, Toshiyuki Murakami
    2013 Volume 133 Issue 12 Pages 1120-1127
    Published: December 01, 2013
    Released: December 01, 2013
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    Recently, two-wheel wheelchair systems had attracted attention since their mobility is better than that of conventional four-wheel wheelchair systems. However, two-wheel wheelchair systems must achieve stabilization control under disturbances caused by modeling error or a road situation since two-wheel wheelchair systems are underactuated systems such as the inverted pendulum. In this study, step passage motion in two-wheel wheelchair systems is considered. A reaction torque observer (RTOB) is employed to estimate the pitch angular interaction torque and the pure external wheel disturbance. Furthermore, repulsive compliance control is employed to determine the optimal pitch angle command to compensate for the center of gravity (CoG) of a human and to assist whole step passage motion. Experimental results are evaluated in terms of comfort for the human by utilizing generalized index ISO2631-1.
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  • Kazuaki Tobari, Kiyoshi Sakamoto, Daisuke Maeda
    2013 Volume 133 Issue 12 Pages 1128-1138
    Published: December 01, 2013
    Released: December 01, 2013
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    We developed a maximum torque control technique for interior permanent magnet synchronous motor (IPMSM) drive systems without position sensors. The conventional maximum torque method (d-axis command operation) cannot achieve a minimum motor current because of parameter errors related to the resistance and q-axis inductance. To solve this problem, we developed a virtual inductance method previously described in another paper. In the current study, we analyzed the robustness in relation to the setting error of motor constants. Time-domain simulations and experiments demonstrated the effectiveness of the proposed method.
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  • Atsushi Baba, Shuichi Adachi
    2013 Volume 133 Issue 12 Pages 1139-1147
    Published: December 01, 2013
    Released: December 01, 2013
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    A rechargeable battery is one of the key technologies in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Although it is important to know the states and parameters of the battery to maximize its efficiency and safety, there are still some difficulties in estimating them. This paper focuses on the simultaneous state and parameter estimation of the battery. The estimation often suffers from poor numerical stability, and to address this issue, simultaneous state and “logarithmic” parameter estimation of batteries is proposed and implemented. This approach is verified by performing a series of simulations under an EV operating environment.
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  • Ryoichi Takahata, Shinichi Wakui, Toshiyuki Ajima, Kenji Miyata, Keiji ...
    2013 Volume 133 Issue 12 Pages 1148-1156
    Published: December 01, 2013
    Released: December 01, 2013
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    This paper describes the influence of the PWM inverter harmonic loss on the concentrated winding interior permanent magnet synchronous motor (IPMSM) characteristics by using a finite element method (FEM) analysis and several measurements. In the measurement, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. Therefore, we presented that the higher inductance of the motor is effective to reduce the harmful effects of the PWM inverter harmonic.
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  • Yuhei Okazaki, Makoto Hagiwara, Hirofumi Akagi
    2013 Volume 133 Issue 12 Pages 1157-1164
    Published: December 01, 2013
    Released: December 01, 2013
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    A modular multilevel cascade inverter based on double-star chopper cells (MMCI-DSCC) is expected as one of the next-generation multilevel PWM inverters for medium-voltage motor drives. This paper presents theoretical and experimental discussions on a practical speed-sensorless start-up method for an induction motor driven by the MMCI-DSCC from a standstill to a middle speed. This motor drive is suitable, especially for a large-capacity fan- or blower-like load, the torque of which is proportional to a square of the motor mechanical speed. Unlike the so-called “volts-per-hertz” control, three-phase stator currents are based on “feedback” control, whereas their amplitude and frequency are based on “feedforward” control. Although the motor drive has no speed sensor attached to the motor shaft, this method makes a slow start-up stable with the help of a stator current-feedback loop. Experimental results obtained from a 400-V, 15-kW downscaled system verify the stable operating performance from a standstill to a middle speed of 590min-1 with a 40% load torque.
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  • Kazunori Nishimura, Yasushi Maehata, Wataru Sunayama
    2013 Volume 133 Issue 12 Pages 1165-1170
    Published: December 01, 2013
    Released: December 01, 2013
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    In recent years, the inspection of power supply facilities can be conducted with high accuracy using remote monitoring technology. In contrast, it is difficult to install sensors at demand facilities because their scale and installation environment differ among customers. As a result, the demand facilities are inspected at fixed time intervals. In this paper, we propose Condition-Based Maintenance (CBM), which improves the maintenance quality at the demand facilities. The proposed method is developed using the maintenance data of demand facilities, which has been collected using Time-Based Maintenance (TBM) thus far, and we conduct analysis primarily using failure data. We use Datamining to analyze transaction data that we modeled based on the maintenance data and to construct the “failure predictive model” that can predict the failure of facilities and its causes from the results of the analysis. By using the constructed model, we will be able to define an object that requires maintenance, which may most likely lead to failures in the future, and this study can contribute to improvement in maintenance technologies for the demand facilities using the proposed CBM.
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  • Kazuhide Domoto, Yoichi Ishizuka, Tamotsu Ninomiya, Seiya Abe, Rejeki ...
    2013 Volume 133 Issue 12 Pages 1171-1178
    Published: December 01, 2013
    Released: December 01, 2013
    JOURNALS RESTRICTED ACCESS
    In an isolated DC-DC converter utilized in a high-voltage DC power distribution system for data centers, a large surge voltage occurs across the secondary-side diodes owing to the transformer's leakage inductance, necessitating diodes with a large withstand voltage. However, these diodes cause large power losses owing to relatively large ON-resistances. First, this study analyzes surge occurrences using a high-frequency equivalent circuit. Second, the surge-suppression capability of a simple snubber capacitor is examined, and the surge-voltage evaluation through analysis using high-frequency equivalent circuits is described. This is followed by experimental confirmation with SiC diodes. Finally, the minimum capacitance of the surge-snubber capacitor is determined for miniaturization.
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  • Noboru Niguchi, Katsuhiro Hirata, Eiki Morimoto
    2013 Volume 133 Issue 12 Pages 1179-1185
    Published: December 01, 2013
    Released: December 01, 2013
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    This paper describes the N-T characteristics of magnetic gear motor in which permanent magnets are used only in the high-speed rotor. The N-T characteristics for the case with and without high-speed rotor slips are computed using finite element analysis under vector control. These characteristics are verified by carrying out measurements on a prototype. Finally, the differences between the computed and measured N-T characteristics are discussed.
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  • Toshihiko Noguchi, Tomohiro Mizuno, Munehiro Murata
    2013 Volume 133 Issue 12 Pages 1186-1192
    Published: December 01, 2013
    Released: December 01, 2013
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    This paper describes a high-speed switching method of MOSFETs applied to a chopper and an inverter. By employing a set of auxiliary switches and diodes in parallel with a load, the turn-off time of the MOSFETs can be reduced, which enables high-frequency operation and reduction of switching loss. It was confirmed through experimental tests that the turn-off dv/dt of the main MOSFETs was effectively improved by the proposed method, particularly in the low-load range.
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