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Shigeru Okuma, Shinji Doki
1996 Volume 116 Issue 8 Pages
808-811
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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Shigeru Omatu
1996 Volume 116 Issue 8 Pages
812-815
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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Emergent Systems
Koji Ito
1996 Volume 116 Issue 8 Pages
816-819
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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Joohn-Sheok Kim, Seung-Ki Sul
1996 Volume 116 Issue 8 Pages
820-825
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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In this paper, a novel voltage modulation scheme is described. With the effective voltage concept, the actual switching times for each inverter arm are deduced directly as a simple form. With the help of the presented zero sequence voltage allocation algorithm, the proposed PWM method has the high performance voltage generation capability exactly same as the conventional space vector PWM method with reduced effort. As well as giving a detailed explanation of the new PWM algorithm, the paper presents the comparison results with the conventional method such as space vector PWM and sinusoidal PWM method. In the proposed PWM method, the execution time can be reduced more than 25% as compared with the conventional space vector PWM method, and memory size will be minimized to 15% of the conventional PWM method.
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Masatoshi Takeda, Shotaro Murakami, Akihiro Iizuka, Yoshifumi Mochinag ...
1996 Volume 116 Issue 8 Pages
826-834
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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This paper describes a self-commutated Static Var Compensator for suppressing voltage fluctuations caused by an a. c. electric railway (Shinkansen, or new trunk line). The a. c. electric railway is a single-phase load with large changes of reactive power and it causes large voltage fluctuations and power unbalances among three phases in the power system.
The authors have developed a new voltage fluctuation compensating system using a self-commutated Static Var Compensator. This system has the functions of reactive power compensation and negative-phase-sequence current absorption and can suppress rapidly-changing voltage fluctuations and reduce the three-phase power unbalance caused by the a. c. electric railway, effectively. This compensating system with a capacity of 40 MVA has been put to practical use for the first time in the world, in 1993. The test results at site show that the system has excellent performance characteristics.
Theoretical analysis on the characteristics of voltage fluctuations with or without the compensating system and the evaluation of the test results including the comparison between the theoretical values and measured ones are also reported.
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Kozo Ide, Koji Hazama, Teruo Tsuji, Ryuichi Oguro
1996 Volume 116 Issue 8 Pages
835-843
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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This paper shows a speed sensorless field-oriented controlled induction motor with a stator voltage error compensator. The speed sensorless field-oriented control needs the measurements of terminal voltages, but the measuring of the instantaneous voltage at the output of a PWM voltage source inverter has difficulty due to harmonic noise, dead time effects, etc. Also the degree of accuracy of voltage measurement deteriorates in low speed range. In order to overcome these problems, the reference voltage is utilized for the observer input in our method, and the error between the reference and the actual voltages are compensated by the estimated voltage error which is in a part of the adaptive observer system. This method improves the accuracy of speed sensorless system without voltage sensor.
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Masahiko Akiyama, Kohji Kobayashi, Ichiro Miki, Mohamed A. El-Sharkawi
1996 Volume 116 Issue 8 Pages
844-851
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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A new auto-tuning method for vector controlled induction motor drives for the start up is presented in this paper. The tuning algorithm is based on the rotor flux behavior of the induction motor for a stepwise torque current command. The inverse of the rotor time constant, which is important for vector control, is tuned using the transient terminal voltage response caused by undesirable variation of the rotor flux. Furthermore, the electrical motor parameters of the induction motor can also be calculated by this method. The validity of the proposed auto-tuning method is verified by experimental results.
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Ichiro Shigaki, Hiroshi Narazaki
1996 Volume 116 Issue 8 Pages
852-861
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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This paper describes a machine learning approach for a manufacturing database in a Nb-Ti superconducting wire domain. A Nb-Ti superconducting wire is produced by iterating the drawing and heat treatment operations. A problem to determine a production schedule, or the parameters in the drawing and heat treatment operations, is discussed. We first show a database approach that selects the most promising schedule to achieve the target superconducting quality from the data. This aproach is useful in the effective reuse of the past experiences, but does not yield a novel production schedule Next we present a machine learning approach to extract knowledge to improve a production schedule for better superconducting quality. We use ID3 method to generalize the data, and we describe two criteria, correctness and applicability indices, to measure the quality of the induced knowledge.
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Fuyuto Takase, Yoshisuke Ueda
1996 Volume 116 Issue 8 Pages
862-867
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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A nonlinear model is proposed which represents air-gap magnetic flux density distribution in a synchronous generator with magnetic saturation. In order to express the effect of saturation in a generator, the authors have measured air-gap flux in specially designed synchronous generator which shows magnetic saturation in the field pole iron cores. In the generator, the total amount of air-gap flux is affected by the saturation of field cores, but the waveform of flux distribution is not affected by the saturation. Therefore we deal with the air-gap permeance and saturation in the field pole cores, separately. By regarding the saturation as a demagnetizing m. m. f. due to a fictitious winding, we construct a magnetic circuitt which represents the flow of magnetic flux inside the generator, and derive an expression for air-gap flux density distribution. Good agreement is obtained between the theoretically calculated results and the measured results by using search coils placed at the teeth of the armature.
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Shu Yamamoto, Takahiro Ara, Masaki Sugiura, Jun Sawaki, Kouki Matsuse
1996 Volume 116 Issue 8 Pages
868-873
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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This paper presents a design method of the Two-Degree-of-Freedom PID position controller for linear servo motor drives. This position controller can be applied to linear servo motor drive systems without a speed minor feedback loop. The proposed method entails calculating all parameter values of this position controller from the mover mass, maximum load mass, thrust constant and cutoff frequency of the position control system. The design method of the Two-Degree-of-Freedom PID position controller and its high-performance position control for linear servo motor drives are described in detail along with the experimental results and simulations.
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DIAPLAN-II
Ayumi Kitagawa, Kenji Kataoka, Kiyotoshi Komaya
1996 Volume 116 Issue 8 Pages
874-882
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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This paper presents a computer aided system for making the train timetable, DIAPLAN-II (Train Diagram Planning Support System). It is designed to prepare the timetable of complicated lines including junctions and sections with different number of tracks such as single, double and four. We have already developed the DIAPLAN for double-track lines. It has employed the integrated framework of simulation and scheduling to emulate human experts' scheduling process on a computer, and it has been successfully applied to the co-operative work between man and computer in the timetable planning. Based on this experience, we employ the same framework to develop our new system. In this system, we define some additional functions to adjust the arrival and departure order of trains at a station in our framework, because it is the critical point for making the timetable of those complicated lines. A timetable generated by DIAPLAN-II shows its usefulness in the co-operative timetable planning.
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Tomotsugu Ishizuka, Kazuyoshi Nezu, Yukihiko Sato, Hiroshi Yamaguchi, ...
1996 Volume 116 Issue 8 Pages
883-884
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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Toshiya Ohnuki, Osamu Miyashita, Katsumi Ohniwa
1996 Volume 116 Issue 8 Pages
885-886
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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Ryozo Itoh, Kouichi Ishizaka, Hidehiko Okada
1996 Volume 116 Issue 8 Pages
887-888
Published: July 20, 1996
Released on J-STAGE: December 19, 2008
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