排序方式: 共有18条查询结果,搜索用时 15 毫秒
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Takashi MINAMI Shohei ARAI Naoki KENMOCHI Hiroaki YASHIRO Chihiro TAKAHASHI Shinji KOBAYASHI Tohru MIZUUCHI Shinsuke OHSHIMA Satoshi YAMAMOTO Hiroyuki OKADA Kazunobu NAGASAKI Yuji NAKAMURA Kiyoshi HANATANI Shigeru KONOSHIMA Fumimichi SANO 《等离子体科学和技术》2013,(3):240-243
A new high repetition rate Nd:YAG Thomson scattering system is developed for the Heliotron J helical device.A main purpose of installing the new system is the temporal evolution measurement of a plasma profile for improved confinement physics such as the edge transport barrier (H-mode) or the internal transport barrier of the helical plasma.The system has 25 spatial points with ~10mm resolution.Two high repetition Nd:YAG lasers (>550mJ@ 50Hz) realize the measurement of the time evolution of the plasma profile with ~10ms time intervals.Scattered light is collected by a large concave mirror (D=800 mm,f/2.25) with a solid angle of ~100 mstr and transferred to interference filter polychromators by optical fiber bundles in a staircase form.The signal is amplified by newly designed fast preamplifiers with DC and AC output,which reduces the low frequency background noise.The signals are digitized with a multi-event QDC,fast gated integrators.The data acquisition is performed by a VME-based system operated by the CINOS. 相似文献
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Novel Transmitting Power Control Method without Signal Communication for Wireless Power Transfer via Magnetic Resonance Coupling 下载免费PDF全文
Wireless power transfer (WPT) via magnetic resonance coupling has been widely studied for vehicle applications, particularly the stationary and dynamic charging of electric vehicles. Our research group previously proposed a wireless in‐wheel motor to improve the reliability and safety of in‐wheel motors. Transmit power control is necessary to achieve stable WPT. We proposed a control method that uses a feedforward controller on the primary side and a feedback controller on the secondary side. However, the control method may cause shortfalls in the transmission power owing to modeling error, coupling coefficient variation, and signal communication delay. In this paper, we propose a novel feedback control method for the primary side based on conversion ratio estimation. The effectiveness of the proposed method was verified by simulations and experiments on the load current control of a constant voltage load and load voltage control of a constant power load. 相似文献
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DAISUKE HIRAMATSU KAZUMA TSUJIKAWA TAKASHI UEDA MASAFUMI FUJITA HIROAKI ISHIZUKA MASASHI OKUBO HIDEYUKI HACHIYA JUNJI MORI DAI NOZAKI DAISUKE IWASHITA TADASHI TOKUMASU 《Electrical Engineering in Japan》2017,198(2):39-49
Fractional‐slot windings are widely used in rotating machines in order to improve the output voltage waveform, increase the design flexibility, and gain many other advantages. However, fractional‐slot windings are known to produce different harmonic components such as an even order and/or fractional number of space flux harmonics compared to integral‐slot windings. These harmonics may increase stray losses and cause stator core vibration. This paper describes an analysis of space flux harmonics and proposes new winding methods such as “novel interspersed windings” to reduce these harmonic components. The proposed winding methods were verified by numerical analysis and model tests. 相似文献
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Inductive Power Transfer systems (IPT systems) for moving Electrical Vehicles (EVs) are often discussed. However, an IPT system for moving railway vehicles has not been sufficiently examined. In order to employ the IPT system for railway vehicles, this paper examines the characteristics of railway IPT systems, such as efficiency, temperature rise, and durability. Because the required characteristics of the IPT system for railway are different from those of EV, one example of a railway IPT system is proposed, and the verification items for practical use are examined. Moreover, we manufactured test equipment that can imitate the field environment in order to verify these items before practical use in the field. The test procedure and test results demonstrate the possibility of practical use of a railway IPT system. 相似文献
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MASASUKE TAKATA DAISUKE TSUBONE HIROAKI YANAGIDA 《Journal of the American Ceramic Society》1976,59(1-2):4-8
The electrical resistivity of ZnO doped with Al2 O3 was measured in air and under reduced pressure (∼0.5 mm Hg) in the range from 30° to 680°C as a function of the degree of sintering. The data obtained were explained in terms of the effects of the microstructure of the sintered body and the chemisorbed oxygen. There are two mechanisms of electrical conduction involved, only one of which is affected by the microstructure. 相似文献
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Railway operators usually do not consider the limit of the electrical energy supply in Japan. Although technologies have been developed for energy efficiency, the limit on the available electrical energy is not considered. However, railway operators met the limit in summer 2011 after the earthquake off the Pacific coast of Tohoku. In this study, we develop an electrical energy allotment method for a large railway network. The method optimizes train operations to provide better railway service when the energy supply is limited. We also develop a search method to find the optimal operation from very large combinations of operation factors. These optimization and search methods are evaluated using the Tohoku earthquake scenario. 相似文献
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RYOTA MATSUO KAZUHIRO YUBAI DAISUKE YASHIRO JUNJI HIRAI 《Electrical Engineering in Japan》2016,197(4):44-52
This paper addresses the model reference control problem, which is a typical control problem found in data‐driven controller tuning methods. For nonminimum phase plants, the unstable zeros of the plant should be included in the reference to avoid destabilization of the resulting closed‐loop system and improve tracking performance. First, we propose a data‐driven controller tuning method with closed‐loop stability taken into consideration and with the tuned controller parameters in the time domain. If the plant has unstable zero(s), the proposed method would not lead to destabilizing controller in the worst case. Closed‐loop stability is checked using linear inequalities described with input/output data. This contributes to reducing computation in the proposed method. Moreover, this paper proposes a data‐driven controller tuning method for nonminimum phase plants estimating the unstable zero(s) using a flexible reference model at each parameter update and reflecting them into the resulting reference model. The effectiveness of the proposed method is confirmed through numerical experiments. 相似文献
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In this study, the lowest loss point is calculated using the permeance method when the machine parameters of the interior permanent magnet synchronous motor are changed. Using the proposed method, the motor loss is easily calculated compared to the conventional method. The periodic change in the magnetic resistance in the air‐gap according to the rotation of the rotor does not need to be considered because the magnetic equivalent circuits of the rotor and stator are separated. In this study, the motor loss is calculated by the proposed method and a finite element method (FEM). As a result, the error in the calculation results between the permeance method and the FEM is 2.9%. On the other hand, the motor losses are calculated by the permeance method when some machine parameters are changed. As a result, these results agree in principle with those of the FEM. Therefore, the validity of the proposed method is confirmed. In addition, the method for motor design is considered in terms of the loss. 相似文献