IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 117 , Issue 2
Showing 1-21 articles out of 21 articles from the selected issue
  • Makoto Hashii
    1997 Volume 117 Issue 2 Pages 119
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Tamotsu Ninomiya
    1997 Volume 117 Issue 2 Pages 120-122
    Published: January 20, 1997
    Released: December 19, 2008
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  • Katsunori Taniguchi
    1997 Volume 117 Issue 2 Pages 123-125
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Seiji Kondo
    1997 Volume 117 Issue 2 Pages 126-128
    Published: January 20, 1997
    Released: December 19, 2008
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  • Mutsuo Nakaoka, Eiji Hiraki
    1997 Volume 117 Issue 2 Pages 129-132
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Hiroshi Takano, Takanobu Hatakeyama, Mutsuo Nakaoka
    1997 Volume 117 Issue 2 Pages 133-141
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The main purpose of this paper is to describe comparatively characteristic features and specific benefits of series, parallel and series-parallel resonant tank type inverter-fed DC-DC power converters with a high-voltage high-frequency transformer link, which are designed for 30kW to 100kW-class medical use X-ray high-voltage generators. The effective method to make the most of the harmful parasitic circuit components of the specially-designed high-voltage transformer used as the three types of resonant circuit topologies is discussed and evaluated on the basis of some simulation performance results for actual wide load variations required for the DC-DC converters in the X-ray generators. Finally, the dynamic output high-voltage responses of these resonant converters are indicated in experiments in order to confirm the unique effectiveness of the resonant tank types power converters treated here.
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  • Katsunori Taniguchi, Katsuya Hirachi, Hisaichi Irie
    1997 Volume 117 Issue 2 Pages 142-149
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A soft-switching circuit for three-phase converter with unity power factor is proposed in this paper. A discontinuous conduction mode converter eliminates the complicated circuit control requirement, reduces a number of components, and reduces the filter reactive components size. In the discontinuous mode converter, the device must be switched off at a maximum inductor current. To achieve the zero voltage switching, the proposed converter is constructed by using a new resonant network in parallel with the switch of the conventional PWM converter. Soft-switched operation of the proposed PWM converter is verified by digital simulation and experimental results. A new PWM converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses.
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  • Hideki Omori, Mutsuo Nakaoka
    1997 Volume 117 Issue 2 Pages 150-159
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Single-ended resonant high-frequency inverters are featured by efficient operation on the basis of soft switching transition mode and simple circuit construction. In recent years, these inverters are applied to the indution-heating cooker, and 3 million units are produced annualy. Miniaturization and cost reduction of these induction-heating inverters are required.
    This paper presents generic circuit topologies of single-ended resonant high-frequency inverters for practical induction-heated cooking appliances. These circuit topologies are classified into 8 categolies, which are derived newly from a view point of the circuit duality concept. Features of all categolies are comparatively described. Two typical voltage-fed circuit topologies of these resonant inverter configrations are analyzed under induction-heated load model. The steady-state performance evaluations are comparatively described and discussed from a practical points of view.
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  • Joohn-Sheok Kim, Jong-Woo Choi, Seung-Ki Sul
    1997 Volume 117 Issue 2 Pages 160-165
    Published: January 20, 1997
    Released: December 19, 2008
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    In voltage-fed PWM inverter, the relation between the reference voltage and the output voltage is nonlinear. Especially, when the currents are around zero point, the nonlinear voltage distortion invokes the most serious problems in the system performance. In this paper, the analysis of the voltage distortion by the zero current clamping phenomenon is discussed. From this analysis, a novel distortion voltage compensation strategy that eliminates zero current clamping is presented. Experimental results are also presented to demonstrate the validity of the proposed method.
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  • Fuyuto Takase, Yoshisuke Ueda
    1997 Volume 117 Issue 2 Pages 166-171
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A nonlinear model is proposed representing air-gap magnetic flux density distribution in a synchronous machine with magnetic saturation in the pole tips. In order to explain the effect of magnetic saturation in a synchronous machine, the authors have measured air-gap flux in a specially designed synchronous machine, and recently proposed a model for the air-gap flux density distribution, concentrating on magnetic saturation in the field pole iron cores. In this paper, we propose an adaptation of our model for calculating air-gap flux, specifically addressing the magnetic saturation in the pole tips. By regarding the saturation as a consumer of m. m. f. similar to a virtual winding, we construct a magnetic circuit which represents the flow of magnetic flux inside the synchronous machine, and derive expressions which represent air-gap flux density distribution. Close agreement is obtained between the theoretically calculated results, and the results measured using search coils placed at the teeth of the armature.
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  • Taiju Suzuki, Hiroaki Ikeda
    1997 Volume 117 Issue 2 Pages 172-181
    Published: January 20, 1997
    Released: December 19, 2008
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    When a megasonic transducer having a low impedance of one ohm or so is connected as a load to the inverter operating in the order of MHz, a snubber circuit is generally used to suppress the surge voltages generated across the switching device.
    This paper analyzes the surge voltage generation and suppression for the single-ended MOS-FET DC-RF inverter feeding an RF power of up to 1kW to the resistive and resonating loads, respectively. A switched snubber of high speed type consisting of an Nchannel MOS-FET and a capacitor is proposed for suppressing surge voltages. Loss power due to the charging and discharging currents flowing through the capacitor in the switched snubber is analyzed and numerically verified. Based on the analysis carried out for the resistive inverter load, the mechanisms of the surge voltage generation and suppression are analyzed for the resonating inverter load. When a megasonic transducer is used as a resonating load, the surge voltage suppression is also described.
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  • Akira Nabae, Akira Yoshikawa, Liyu Cao, Toshihiko Tanaka
    1997 Volume 117 Issue 2 Pages 182-188
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Conventionally, the active, reactive and apparent powers in three-phase circuits have been defined by extending the concept based on the RMS values of voltage and current with respect to time in single-phase circuits. Applying the definition based on single-phase circuits to three-phase systems with non-sinusoidal conditions has resulted in many options in the methods of power properties description, interpretation and compensation, and this has led to a controversy on which method should be chosen, or on how power quantities should be defined. This paper proposes a new definition of the instantaneous active-reactive current and power based on instantaneous space vectors on polar coordinates in three-phase circuits. The instantaneous active-reactive power and current are defined in the voltage-current vector plane without any special fictitious power. The new definition proposed here leads to the same formulas as the conventional ones. The authors claim that this is a great advantage of the new definition. Comparing it to the p-q theory, we discuss the new definition in detail. It is shown that using the new definition one is able to calculate the instantaneous active-reactive power and current directly from the voltage and current space vectors. The new definition, thus, offers a lucid concept of electric power in three-phase circuits. Using digital simulation, an application example is shown to confirm the validity and practicability of the new definition.
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  • Hideo Okayama, Taichiro Tsuchiya, Yasuhito Shimomura
    1997 Volume 117 Issue 2 Pages 189-195
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Increase in the capacity of GTOs has made remarcable progress in recent years. At present, 4.5kV-4.0kA GTOs are commercially available. Now, 6kV-6kA GTOs which are made from 6-inch silicon wafer are developing. The 6-inch GTOs are going to be applied to our 3-level GTO inverter system. In order to apply GTOs to voltage-source-inverters snubber circuits are necessary for limiting on turn-on di/dt and turn-off dv/dt. To realize the system of high efficiency, regenerative snubber circuit is applied. A conventional circuit, which could be applied to 3-level GTO inverter, had a problem that long paths are created for snubber circuits of inner GTOs. In order to solve the problem, a circuit using a transformer which is provided for recovering the trapped energy of snubber circuits for inner GTOs was presented. In this paper, newly regenerative snubber circuit is proposed, which is more suitable for 3-level GTO inverter system with many phase-legs. By applying this snubber circuit, snubber energy generated by the switching of all GTOs' in the main circuit can be regenerated to DC-link capacitors. High turn-off capability of both inner GTO and outer GTOs are verified by several successful experimental results using 6-inch (6kV, 6kA) GTO.
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  • Noriaki Kamigaito, Yasumasa Kubota, Shigeo Masukawa, Shoji Iida
    1997 Volume 117 Issue 2 Pages 196-203
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A new method for reducing harmonics involved in ac line currents of a three phase voltage source onverter is proposed. It is applied to the conventional Neutral-Point-Clamped inverter. By dividing a smoothing capacitor into four elements and adding four auxiliary switching devices, input line-to-line voltages of the proposed converter can be almost the same waveforms as a conventional 18-phase rectifier with 18 devices and three input transformers.
    In this paper, circuit performances and input voltage waveforms are discussed, and the optimum parameters are determined. Effects of harmonic reductions can be clarified by theoretical results. Then, we suggest several adjusting methods of the output voltage. Characteristics of power factors and distortion factors in these methods are theoretically and experimentally investigated.
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  • Masayuki Yasumura
    1997 Volume 117 Issue 2 Pages 204-212
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Recently, soft switching power supply by resonant type converter is widely taken notice, which has high efficiency and low noise characteristics principally. Conventional resonant type converter has a complex control circuit, and we solved this problem by using cross transformer. Now, various types of switching power supplies, which have a simple structure, are realised by combination of self oscillating driving circuit and resonant type converter. This paper presents our process of the development and the latest technology of soft switching power supply which is enabled by super small-sized cross transformer.
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  • Min Wu, Michio Nakano, Jin-Hua She
    1997 Volume 117 Issue 2 Pages 213-220
    Published: January 20, 1997
    Released: December 19, 2008
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    Two important aspects of the control of the coal blending process in the iron and steel industry are computation of the target percentage of each type of coal to be blended and the blending of the different types of coal in the target ratio. This paper presents an expert control system with a two-level configuration for the coal blending process. First, based on statistical data and knowledge of the process, highly accurate mathematical models are constructed to predict the quality of blended coal and coke. Based on the knowledge representation, rule models are established to compute the target percentages and modify the mathematical models. Then, an algorithm for computing the target percentages is proposed that combines the mathematical models and rule models and uses a forward chaining strategy. Finally, a distributed control system is constructed for the blending of coal in accordance with the target percentages. The results of actual runs show that the expert control system provides an effective way to control the coal blending process.
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  • Masayoshi Kamiya, Hiroaki Ikeda
    1997 Volume 117 Issue 2 Pages 221-230
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper describes the optical signal transmission system constructed using direct intensity modulation technique which is capable of transmitting a signal through a movable optical fiber, and its application to the measurement of dimensions using a robot. When the optical fiber is bent, the optical power losses are increased, and however, the power loss at 830nm was almost the same as that at 660nm. So, the light at 660nm can be used as a reference light to correct the intensity error of the signal light at 830nm which is caused by the optical fiber bending. This system simultaneously transmits the signal and reference from a transmitter to a receiver through a movable optical fiber. At the receiver, the signal is normallized by the reference to provide the correct output signal. When the optical fiber was bent with a bending radius of 10mm at a bending angle of 180 degrees, the transmission error rate was 0.28 in the conventional single-path system. This error was caused by the bending loss of the signal light power. Under the same bending conditions, the error rate was improved to 0.03 in the proposed system due to the reference capability. This system was experimentally applied to transmit data from the displacement sensor attached to the arm of the robot through the movable optical fiber installed in the arm of the robot. The proposed system having the reference capability can transmit an optical distance signal with the minimum error through a movable optical fiber. The experiment was successful.
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  • Munetoshi Unuma, Shirou Nonaka, Yoshiaki Usami, Toshiaki Yoshinaga
    1997 Volume 117 Issue 2 Pages 231-237
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Various techniques to create virtual environment using design data of power plants are presented.
    In order to realize interactive operations on virtual environment, it is necessary to achieve the real-time processing of drawing and interference check. However, real-time processing is very difficult in the case of large-scale and complicated buildings like power plants, because of the large number of shapes.
    In this paper, we propose the abbreviation drawing technique that changes the drawing area dynamically to keep the drawing time constant, and the fast interference check technique that utilizes the hardware projection processing. And it is confirmed that the processing can be realized within 200 msec by applying the prototype system to real power plants.
    Moreover, we propose the navigation technique that enables users explore inside of the complicated virtual power plants and show the rapidness and effectiveness of the technique.
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  • Hitoshi Hayashiya, Noboru Araki, Jonathan E. Paddison, Hiroyuki Ohsaki ...
    1997 Volume 117 Issue 2 Pages 238-244
    Published: January 20, 1997
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    A magnetic levitation system is applied to the non-contacting conveyance of steel plate in a steel mill. In this system, the flexibility of the steel plate may deteriorate the levitation characteristic and so it is proposed to arrange the electromagnets along the steel plate length. A low pass filter is used to reduce the influence of the steel plate natural vibrations. Simulation results of the levitated plate's response by a finite element method and magnetic levitation experiments are presented. The results show the vibration suppressing electromagnet which only uses the velocity of the levitated object as a feedback is able to control the low frequency natural vibration effectively and a low pass filter is able to avoid the excitation of the high frequency natural vibration.
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  • Moriaki Takechi
    1997 Volume 117 Issue 2 Pages 245-254
    Published: January 20, 1997
    Released: December 19, 2008
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    This paper describes an analytical study on magnetic shielding by a set of superconducting windings for applications such as low magnetic field measurement using SQUIDs (superconducting quantum interference device) and magnetic resonance imaging. Fundamental equations to be satisfied by the coil system are studied and a direct method to determine coil parameters are proposed. The proposed method was applied to obtain coil configurations for shielding axial external magnetic field with spatial distribution of uniform or linear gradient along axis. Comparison of the shielding factor proves that superconducting windings can achieve better shielding factors than superconducting cylinder with same aspect ratio.
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  • Shoji Nishikata, Makoto Nakamura
    1997 Volume 117 Issue 2 Pages 255-256
    Published: January 20, 1997
    Released: December 19, 2008
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