• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.548-551
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• 2004

Magnetostrictive actuators have seen increasing use in fine positioning system because it has many advantages such as friction free, resolution of ${\mu}{\textrm}{m}$ or nm scale, and powerful output force. Usually, the magnetic circuit of magnetostrictive actuator has components which are flux return path, coil, and magnetostrictive material. It is classified in two types according to existence of the permanent magnet. The magnetic circuit having optimal performances transfer magnetic field which is obtained by providing input current at coil without energy loss. This paper described mathematical model of magnetic circuit for getting design variables. The modeling equation is obtained from the relations between flux and reluctance of the magnetic equivalent circuit. Also, finite element analysis has been used to study the performance of magnetic circuit according to change of design variables such as existence and shape of the permanent magnet, flux return path etc. The modification of dimensions enables us to optimize magnetic circuit.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1138-1146
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• 2018

Performance comparisons of switched reluctance motor for cooling fan application are dealt in this paper. Conventional and novel segmental type motors with the same dimension are compared. The conventional 12/8 type is very popular and used widely. The structure of segmental rotor type motor is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. This type of motor has short flux path and no flux reversal in the stator. The auxiliary poles are not wound by the windings and only provide the flux return path. Compared with conventional SRM, the segmental structure increases electrical utilization of the machine and decreases core losses, which leads to higher efficiency. To verify the segmental structure, finite element method (FEM) is employed to get static and dynamic characteristics of both SRMs. Finally, the prototypes of conventional and segmental SRMs are tested for characteristics comparisons.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.39-40
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• 2014

In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed. Different from conventional structures, the proposed rotor consists of a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure short flux paths are taken and no flux reverse exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. Compared with conventional 12/8 SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to high efficiency. To verify the proposed structure, finite element method (FEM) is employed to get static and dynamic characteristics. Finally, a prototype of the proposed motor is tested for characteristics comparisons.

• Journal of Power Electronics
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• v.14 no.5
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• pp.866-873
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• 2014

In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed for cooling fan applications. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure, short flux paths are taken and no flux reversion exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. When compared with the conventional SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get the static and dynamic characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

• Journal of Magnetics
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• v.4 no.3
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• pp.98-101
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• 1999

In this work we htave constructed an under water sonar transducer using Terfenol-D rod employing open magnetic circuit. Normally Sonar transducer using Terfenol-D was designed under closed magnetic flux return path, and permanent magnet for dc bias marnetic field, but high magnetic field should be applied to the transducer coil for high sound power and it brings temperature increase inside of the transducer. To improve this heat dissipation problem, we have designed an open magnetic circuit type transducer and we can get 200 dB (re. 1 Pa @ 1m) sound power for the input power of 650 VA.