電気学会論文誌D(産業応用部門誌)
Online ISSN : 1348-8163
Print ISSN : 0913-6339
131 巻 , 11 号
選択された号の論文の29件中1~29を表示しています
特集:回転機技術
巻頭言
特集論文
論文
  • 照屋 大輔, 枡川 重男, 飯田 祥二
    2011 年 131 巻 11 号 p. 1324-1330
    発行日: 2011/11/01
    公開日: 2011/11/01
    ジャーナル 認証あり
    We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.
  • Junji Shibata, Kazuhide Kaneko, Kiyoshi Ohishi, Itaru Ando, Mina Ogawa ...
    2011 年 131 巻 11 号 p. 1331-1337
    発行日: 2011/11/01
    公開日: 2011/11/01
    ジャーナル 認証あり
    This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.
  • 新井 卓郎, Ben York, 藤田 英明
    2011 年 131 巻 11 号 p. 1338-1345
    発行日: 2011/11/01
    公開日: 2011/11/01
    ジャーナル 認証あり
    This paper describes a power-transfer principle and power-loss analysis of phase-shift-controlled switched-capacitor-based resonant converters (PSC-SCRC). Power loss in the PSC-SCRC is theoretically derived and compared with that in a conventional switched-capacitor converter (SCC) and a frequency-controlled SCRC (FC-SCRC). As a result, it is clarified that a PSC-SCRC has no theoretical power loss unlike an SCC and an FC-SCRC. The experimental results agree well with the theoretical ones.
  • 加藤 利次, 井上 馨, 吉田 圭亮
    2011 年 131 巻 11 号 p. 1346-1353
    発行日: 2011/11/01
    公開日: 2011/11/01
    ジャーナル 認証あり
    In an AC motor, the quick detection of an initially small fault is important for preventing any consequent large fault. Various detection approaches have been proposed in previous papers, for example, by the Park vector (PV), AI techniques, wavelet analysis, and negative-sequence analysis. This paper proposes a method for diagnosing the stator-winding faults of an induction motor by the direct detection of its negative-sequence current. Before starting the diagnosis, the asymmetry admittances for the considered fault cases are obtained by analysis or simulation. The amplitude and phase of the positive-sequence voltage, Vp, and of the positive-sequence current, Ip, are extracted from the voltage PV and current PV, respectively. The amplitude and phase of the negative-sequence, In, are extracted from the residue. The asymmetry admittance, Ya, is calculated from In and Vp. When the positive-sequence admittance is known, Ya can also be calculated from Yp, Ip, and In. These steps are repeated for each sample time and the motor condition is diagnosed according to the variations in the Ya values. The simulation and experimental results are also shown and the proposed method is investigated and validated.
  • 藤田 重人
    2011 年 131 巻 11 号 p. 1354-1359
    発行日: 2011/11/01
    公開日: 2011/11/01
    ジャーナル 認証あり
    High-frequency voltage oscillation is occasionally observed in bipolar power semiconductors during a turn-OFF operation. The mechanism of generation of the turn-OFF oscillation is explained by the plasma extraction transit-time (PETT) oscillation theory. According to this theory, a packet of holes propagate through the drift region with constant velocity and induce current flow in the external circuit. The waveform of the corresponding current density is trapezoidal. Negative resistance is generated in the circuit by the current density and RF voltage applied to the semiconductors. The negative resistance is the origin of generation of the turn-OFF oscillation. The author investigates the generation of the IGBT turn-OFF oscillation by performing a 2D device simulation. The simulation results show generation of the negative resistance is different from that described in the PETT oscillation theory. The velocity of the packet of holes depends on the electric field in the drift region and is not constant. The simulated current density oscillates with an almost negative phase compared to the RF voltage oscillation. Further, on the basis of the simulation results, the author will propose the practical method to estimate the oscillation frequency in this paper.
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