Faculty Profiles - UEDA Hiroshi

Operational Characteristics of Linear Synchronous Actuator With Field-Cooled HTS Bulk Secondary Reviewed International journal

A. Sato, H. Ueda, A. Ishiyama

IEEE Transactions on Appiled Superconductivity 15 ( 2 ) 2234 - 2237 2005.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Electrical and Electronics Engineers (IEEE)

It is expected that HTS bulk materials will be applied to various electric devices. We have fabricated and tested a linear synchronous actuator with double-sided primary and HTS bulk secondary. The linear actuator consists of a field-cooled YBCO bulk for secondary (mover) and copper windings with iron core as a primary. The primary, which was excited by a three-phase VVVF power source to generate sinusoidal traveling magnetic field, was divided into two sections: 1) the starting section in which the secondary is accelerated as an induction machine; and 2) the synchronous section in which the secondary moves with a specified synchronous speed. As the secondary, two field-cooled bulks were arranged in certain interval. In this paper, for various intervals of bulks, we experimentally investigated the static characteristic in points of synchronous thrust force and the pull-in characteristics. And we developed a simulation program based on the finite element method (FEM) to investigate electromagnetic behavior within the bulk exposed to the magnetic field generated by the primary winding. We investigated the influence of the size, the number, and the interval of bulks on the static characteristic in points of synchronous thrust force by using the developed computer program. © 2005 IEEE.

DOI： 10.1109/tasc.2005.849619

Transient Thermal Characteristics of Cryocooler-Cooled HTS Coil for SMES Reviewed International journal

A. Ishiyama, M. Yanai, T. Morisaki, H. Ueda, S. Akita, S. Kouso, Y. Tatsuta, H. Abe, K. Tasaki

IEEE Transactions on Appiled Superconductivity 15 ( 2 ) 1879 - 1882 2005.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Electrical and Electronics Engineers (IEEE)

Thermal behavior of high-temperature super-conducting (HTS) coil is exceedingly different from that of low-temperature superconducting (LTS) coil. Therefore for the sake of the application of HTS coil to practical use, establishment of a new stability criterion for coil design becomes indispensable. In this study, a small-sized cryocooler-cooled HTS coil wound with Bi-2223/Ag tape was constructed and tested to evaluate the electromagnetic and thermal characteristics in the cryocooler-cooled HTS coil. We carried out experiments subjected to pulse current operation supposing SMES for power system stabilization. The simulation by a newly developed computer program based on the finite element method (FEM) agreed well with experimental results. In the computer program, short-sample data concerning the E-J characteristics, which depend on the orientation of applied magnetic field to the wide face of Bi-2223Ag tape, was adopted. By using the computer program, we also evaluate the thermal behavior of HTS coil graded according to the magnetic field distribution. © 2005 IEEE.

DOI： 10.1109/tasc.2005.849321

Fundamental Characteristics and 3D Electromagnetic Analysis for Magnetic Levitation Transporter using YBCO Bulk Superconductors Reviewed

Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field Reviewed

Hiroshi Ueda, Atsushi Ishiyama, Tohru Morisaki

IEEJ Transactions on Power and Energy 124 ( 11 ) 1357 - 1364 2004.11

Hiroshi Ueda, Mami Iwamoto, Yuhya Kudo, Atsushi Ishiyama

IEEJ Transactions on Power and Energy 124 ( 10 ) 1200 - 1208 2004.10

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Institute of Electrical Engineers of Japan (IEE Japan)

We have been developing a magnetic levitating device with two-dimensional movement, namely a ’levitating X-Y transporter’. For a real design of the levitating X-Y transporter, it is necessary to clarify the levitation characteristics, such as lift, levitation height and stability against mechanical disturbances. In this paper, we examine the lift and the restoring force experimentally and newly developed a simulation code based on the three-dimensional hybrid finite and boundary element method to analyze the dynamic electromagnetic behaviors of YBCO bulk. We investigated the suitable permanent-magnet arrangement to enhance the levitation characteristics through experiments and numerical simulation. And we also performed the design of a levitating transporter which can levitate a load of 200kg with a gap of 16mm.

DOI： 10.1541/ieejpes.124.1200

Lift and restoring force characteristics of a levitating X–Y transporter using high-temperature superconducting bulks Reviewed International journal

M Iwamoto, H Ueda, A Ishiyama

Superconductor Science and Technology 17 ( 8 ) 1042 - 1045 2004.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

We have been investigating the electromagnetic behaviour of HTS bulks for realizing an X-Y (two-dimensional) magnetic levitating transporter without any fixed guides. The transporter is mainly composed of disc-shaped YBCO bulks and Nd-Fe-B permanent magnets or field-cooled YBCO bulks. The lower part and the upper part (levitating part) are magnetically connected. In such a 'levitating X-Y transporter', it is necessary to comprehend the characteristics, such as the lift, the levitation height and the stability against mechanical disturbances. In this paper, we evaluated the lift and the restoring force characteristics experimentally in the case where a field-cooled YBCO bulk is adopted instead of permanent magnets and also developed a numerical simulation program based on the finite element method to clarify the electromagnetic phenomenon in the HTS bulks.

DOI： 10.1088/0953-2048/17/8/017

Preliminary experiments of a tubular linear actuator in the vertical direction using YBCO bulk Reviewed International journal

A Sugawara, H Ueda, A Ishiyama

Superconductor Science and Technology 17 ( 5 ) S176 - S179 2004.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

The preliminary experiments of a tubular linear actuator in the vertical direction using YBCO bulk was studied. In active-maglev systems the leviation height was adjusted by varying the operating current through an electromagnet. Synchronous operations by a travelling magnetic field generated by using a three-phase aiternating current was achieved. The primary consists of six ring-shaped copper-winding coils without iron core and was supplied with three-phase sinusoidal excitation. The electromagnetic phenomenon within the bulk superconducted was also studied using a computer program based on the finite element method.

DOI： 10.1088/0953-2048/17/5/017

Dynamic characteristics and finite element analysis of a magnetic levitation system using a YBCO bulk superconductor Reviewed International journal

H Ueda, A Ishiyama

Superconductor Science and Technology 17 ( 5 ) S170 - S175 2004.5

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

We have been developing a magnetic levitating device with two-dimensional movement, namely a 'levitating X-Y transporter'. For the real design of a levitating X-Y transporter, it is necessary to clarify the levitation characteristics, such as the lift, the levitation height and the stability against mechanical disturbances. Furthermore various kinds of force may be applied to the levitating part and cause mechanical oscillation. Therefore the characteristics of oscillation are also important factors in the dynamic stability of such a levitation system. In this paper, we examine experimentally the lift and the restoring force and develop a new simulation code based on the three-dimensional hybrid finite and boundary element method to analyse the dynamic electromagnetic behaviour of the HTS bulk. We have investigated a suitable permanent-magnet arrangement to enhance the levitation characteristics through experiment and numerical simulation. We can then determine the suitable conditions for stable levitation from those results.

DOI： 10.1088/0953-2048/17/5/016

YBCO線材の常電導転移・伝播特性評価 Reviewed

石山敦士, 柳井正浩, 植田浩史, 飯島康裕, 斉藤隆, 塩原融

低温工学 39 ( 2 ) 560 - 566 2004.2

A new type of active-Maglev system using YBCO bulk and multiple electromagnets Reviewed International journal

R. Kamoshida, H. Ueda, A. Ishiyama

IEEE Transactions on Appiled Superconductivity 13 ( 2 ) 2157 - 2160 2003.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Institute of Electrical and Electronics Engineers (IEEE)

We have been developing a new type of active-maglev system that is a transporter in the vertical direction, consisting of high-temperature bulk superconductors and multiple electromagnets piled up on the vertical axis. In a previous paper, using an active-maglev system composed of a disk-shaped YBCO bulk and five electromagnets, we have demonstrated continuous levitation and verified that its levitation height, as well as stability, can be remarkably improved by adjusting the operating current of the electromagnets individually. Electromagnetic behavior within the bulk has been also investigated numerically by a newly developed computer program based on the finite-element method adopting the Bean model. Agreement of levitation force and height between experiments and numerical analyses was good. The levitation force properties strongly depend on the field-cooling condition and the distribution and magnitude of the external magnetic field generated by the electromagnets. We clarify electromagnetic phenomena within the bulk superconductor by the computer program developed to improve the levitation properties for applications of continuous levitation to real maglev systems.

DOI： 10.1109/tasc.2003.813023

Performance evaluation of continuous levitation in an active-maglev system using YBCO bulk and multiple electromagnets Reviewed International journal

H Ueda, H Hayashi, A Ishiyama, M Tsuda

ELECTRICAL ENGINEERING IN JAPAN 141 ( 2 ) 25 - 33 2002.11

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SCRIPTA TECHNICA-JOHN WILEY & SONS

We have designed and constructed a new type of active-maglev system using YBCO bulk and two electromagnets and have demonstrated that levitation height was remarkably improved by continuous levitation. In the active-maglev system, however, the upper and lower coils differed in the coil size and an iron plate beneath the lower coil was used to enhance the magnetic field around the bulk. Considering the real application to maglev transporter in the axial direction, we must realize continuous leviation using a larger number of electromagnets without such iron plate and enable the levitation height to be controlled freely. In this paper, we demonstrate continuous levitation while controlling the leviation height using three- and five-electromagnet systems and investigate electromagnetic behavior within the bulk using an FEM computer program. (C) 2002 Wiley Periodicals, Inc.

DOI： 10.1002/eej.10055

A new type of active-maglev system using YBCO bulk and multiple electromagnets Reviewed

Hayashi, H., Ueda, H., Tsuda, M., Ishiyama, A., Hamajima, K.

IEEE Transactions on Applied Superconductivity 12 ( 1 ) 907 - 910 2002.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

We present a, new type of active-maglev system consisting of a disk-shaped superconducting bulk (YBCO) and multiple electromagnets. Using the active-maglev system composed of five electromagnets, we demonstrated. continuous levitation and verified that the levitation height, as well as stability, could be remarkably improved by adjusting operating current of electromagnet individually. Electromagnetic behavior within the bulk was investigated numerically by the finite element method (FEM) adopting the Bean model. Agreements of levitation force and height between experiment and analysis were good. Suitable electromagnet operation for continuous levitation in terms of consumed operating energy was also investigated. It was found in analysis that continuous levitation could be realized efficiently by adopting a three-electromagnet operation and the operating procedure is applicable to multiple-electromagnet system. Therefore, based on the assumption of constant total operating current of three electromagnets, we numerically investigated the relationship between the operating procedure and levitation force in a five-electromagnet system as a function of levitation height. Maximum allowable weight of float (superconducting bulk and load) was evaluated through the estimation of minimum levitation force during continuous levitation as a function of air gap between electromagnets.

DOI： 10.1109/TASC.2002.1018547

Trial Design of 6.6 kV Magnetic Shielding Type of Superconducting Fault Current Limiter and Performance Analysis Based on Finite Element Method. Reviewed

門裕之, 市川路晴, 植田浩史, 石山敦士

電気学会超電導応用電力機器研究会資料 122-B ( 8 ) 944 - 950 2002.8

Characteristics of active-maglev system using YBCO bulk and multiple electromagnets Reviewed International journal

H Ueda, H Hayashi, A Ishiyama, M Tsuda

PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 372 ( 3 ) 1466 - 1469 2002.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

One useful feature of the active-maglev system is that levitation height is adjustable by varying operating current in electromagnets. To improve the levitation height, we have designed and constructed a new type of active-maglev system with two electromagnets instead of using a larger single electromagnet. The levitation height, as well as stability, was remarkably improved by adjusting the operating current of each electromagnet individually. Although the bulk is levitated up to high position, the lower electromagnet is continued to operate in continuous levitation using multiple electromagnets. It is waste that the lower electromagnet is continued to operate. The required energy for the electromagnet operation should be minimized. In this paper, we tried to realize continuous levitation with keeping the total operating current constant in five-electromagnet active-maglev system and investigate electromagnetic behavior within the bulk using a newly developed FEM computer program. Continuous levitation was successfully achieved under the desired operating condition. Agreements between experiment and analysis were excellent. (C) 2002 Published by Elsevier Science B.V.

DOI： 10.1016/S0921-4534(02)01050-X

Trial production and experiment of linear actuator with double-sided primary and HTS bulk secondary Reviewed

S Sadakata, H Ueda, M Tsuda, A Ishiyama

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 12 ( 1 ) 824 - 827 2002.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

It is expected that HTS bulk materials are applied to various electric devices. In a previous work we have fabricated and tested a linear actuator with single-sided primary and HTS bulk secondary. The linear actuator was comprised of zero-field-cooled YBCO bulk for secondary (mover) and copper windings with iron core (primary). The primary was excited by a three-phase VVVF power source to provide sinusoidal traveling field. To improve the characteristics of the linear actuator, we newly designed and fabricated a linear actuator with double-sided primary and zero-field-cooled HTS bulk secondary. We measured starting thrust force and magnetic field distribution in the air gap between the bulk and the primary iron core at the stationary state. To evaluate dynamic characteristics of the linear actuator, we numerically investigated electromagnetic behavior within the bulk exposed to time-varying magnetic field using a simulation program based on the finite element method (FEM) taking the voltage-current (E-J) characteristic into consideration. Computed starting thrust force, displacement characteristic and field distribution between the bulk and the primary iron core were compared with the experimental results. Agreement between experiments and analyses was good. We also investigated the electromagnetic characteristics as a linear synchronous actuator with double-sided primary and field-cooled HTS bulk secondary.

DOI： 10.1109/TASC.2002.1018528

Trapped field characteristics of Y-Ba-Cu-O bulk in time-varying external magnetic field Reviewed

H Shimizu, H Ueda, M Tsuda, A Ishiyama

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 12 ( 1 ) 820 - 823 2002.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

It is very important to clarify characteristics of trapped field in HTS bulk exposed to an external AC magnetic field in application of high-temperature superconducting bulk to motors, magnetic levitation systems, bulk magnets and so on. We have experimentally investigated the transition of trapped field while applying external AC magnetic field to a disk-shaped YBCO bulk. The observed trapped-field attenuation is different from that by flux creep, i.e., zero external field. It may be considered that the trapped-field attenuation is affected by external AC magnetic field, particularly temperature rise due to AC loss. In this paper, electromagnetic behaviors within the bulk exposed to external AC magnetic field, especially supercurrent distribution, are investigated numerically using a simulation code based on the finite element method (FEM) considering voltage-current (E-J) characteristic. We focus on the relationship between the transition of supercurrent distribution within the bulk while applying external AC magnetic field and both n-value of E-J characteristic and temperature rise by AC loss.

DOI： 10.1109/TASC.2002.1018527

Static and dynamic characteristics in levitating X-Y transporter using HTS bulks Reviewed International journal

Teranishi, Y., Ueda, H., Tsuda, M., Ishiyama, A.

IEEE Transactions on Applied Superconductivity 12 ( 1 ) 911 - 914 2002.3

バルク超電導体と複数の電磁石による鉛直方向連続アクティブ磁気浮上の特性評価 Reviewed

植田浩史, 林浩幹, 石山敦士, 津田理

電気学会論文誌B（電力・エネルギー部門誌） 121-B ( 10 ) 1331 - 1338 2001.10

Characteristics of lift and restoring force in HTS bulk - Application to two-dimensional Maglev transporter Reviewed

Y Sanagawa, H Ueda, M Tsuda, A Ishiyama, S Kohayashi, S Haseyama

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 11 ( 1 ) 1797 - 1800 2001.3

Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

One of the advantages of magnetic levitation using high-temperature superconducting (BTS) bulk is that stable levitation can be achieved without any control systems. We have been investigating the electromagnetic behaviors of HTS bulk to realize a two-dimensional magnetic levitating transporter without any aired guides, The characteristics of lift and stability are key parameters to design and optimize such a device. We measured the lift and the restoring force of a YBCO bulk, displaced by a distance in lateral direction, for various field-cooling conditions and permanent-magnet arrangements, Both lift and restoring force are closely related to the air gap in the field-cooling process, distance between the permanent magnets, number of permanent magnets, and permanent magnet arrangement, that is, external magnetic field distribution. The most suitable arrangement of permanent magnets depends on the required levitation height and the weight of the levitating part. It can be considered that the size of the levitating part and geometry are also very important to determine the optimal arrangement in the maglev device.

DOI： 10.1109/77.920135