• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1686-1694
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• 2015

Stator tooth segmentation and back-iron segmentation is key solution to easing the burden of manufacturing process of permanent magnet synchronous motor. The purpose of this paper is the design and characteristic analysis of permanent magnet synchronous motor having the segmented phase modular stators. Using by two-dimensional finite element method, the static/no-load characteristic analysis of the permanent magnet synchronous motor is performed. The analysis has been performed considering the additional air gaps between stator modules. The analysis results were experimentally verified, and the validity of the proposed analysis method and feasibility of the machine was confirmed.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1029-1031
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• 2005

A magnetic position sensor is a apparatus that detect the rotating position by measuring the value of the flux density of the rotating position. In this paper, the magnetization system of the permanent magnet in the magnetic position sensor which detects the rotating position was designed. The permanent magnet was magnetized for the flux density into the hole element to be sinusoidal distribution according to the rotating position. To make the sinusoidal distribution of flux density, the magnetization values according to the position in permanent magnet were varied by adjusting the air gap between the pole of the magnetization fixture and the surface of the permanent magnet.

• Journal of the Korean Magnetic Resonance Society
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• v.23 no.3
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• pp.81-86
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• 2019

Overhauser dynamic nuclear polarization (O-DNP) has been an efficient method to boost the thermal nuclear polarization in liquids at room temperature. However, O-DNP for a benchtop NMR using a permanent magnet has remained unexplored yet. In this work, we report the development of an O-DNP system adopting a permanent magnet of 1.6 T. Q-band (~43 GHz) high-power amplifier produced 6 W microwave for saturation. Instead of resonator, we used an open-type antenna for the microwave irradiation. For several representative small molecules, we measured the concentration and frequency dependences of the enhancement factor. This work paves the way for the development of a benchtop DNP-NMR system overcoming its disadvantage of low quality signal when using a permanent magnet.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1832-1837
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• 2011

This paper presents the optimal permanent magnet shape on the rotor of an interior permanent magnet motor to reduce the core losses and improve the performance. As permanent magnet has conductivity inherently, it causes huge amount of eddy current losses by the slot harmonics with concentrated winding. This loss is roughly 100 times larger than that of distributed winding in high speed operation and it cannot be ignored, especially on traction motors. Each eddy current loss on permanent magnet has been investigated in detail by using FEM(Finite Element Method) instead of EMCNM(Equivalent Magnetic Circuit Network Method) in order to consider saturation and non-linear magnetic property. Simulation-based DOE(Design Of Experiment) is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, the core loss reduction on the proposed shape of the permanent magnet is verified by FEM.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.88-93
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• 2008

The electromagnetic parameters of a permanent magnet synchronous motor (PMSM) such as the open load permanent magnet flux, d axis reactance $X_d$, and q axis reactance $X_q$, are most essential to the performance analysis and optimization design of the motor. Based on the numerical analysis of the 3D electromagnetic field, the three electromagnetic parameters of permanent magnet synchronous motors with U form interior rotor structures are calculated by FEA. The rules of the leakage coefficient and reactance parameters changing with the air gap length, permanent magnet magnetism length, and isolation magnetic bridge dimensions in the rotor are given. The calculated values agree well with the measured values. The FEA results are integrated with the self compiled electromagnetic design program to optimize the prototype motor. The tested performances of the prototype motor prove that the method is suitable for the optimization of motor structure.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.398-402
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• 2014

This paper presents the comparison study of permanent magnet (PM) eddy current of concentrated winding type surface permanent magnet synchronous motor (SPMSM) with different rare-earth magnet shapes. The fractional slot winding having 10 poles and 12 slots is studied. The PM eddy current is analyzed to compare for each shape by 2 dimensional (2D) finite element analysis (FEA). The eddy current and their loss of particular position of PM as well as their distributions are displayed for each model. The effect of partly enlarged air-gap made by PM shape to PM eddy current is compared.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.124-126
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• 2006

In this paper, a synchronous permanent magnet planar motor (SPMPM) with new permanent magnet array is proposed and the magnetic field distribution is obtained analytically by using magnetic scalar potential. Compared to those of Asakawa, Chitayat and experimental data, the superiority and feasibility of the novel magnet array are verified. The characteristics of the synchronous permanent magnet planar motor with this novel magnet array such as inductance, back-EMF, and force are calculated by analytical method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.81-87
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• 2005

The torque characteristics of permanent magnet(PM) motor is varied according to magnet width. In this paper, the design method of magnet and magnetic circuit is proposed in order to improve the torque of Interior Permanent Magnet Synchronous Motor(IPMSM). This paper presents the effects of pole arc ratio and salient pole ratio on the torque and torque ripple in the IPMSM with concentrated winding.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.98.1-98
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• 2001

An actuator using a permanent magnet and solenoid is proposed and designed in this paper. Its design concept is composed of a driving force generation, a guide mechanism, and a symmetric structure. At first, Driving Force generation uses a concept that is a change efflux by using a permanent magnet and solenoid. A permanent flux is generated by a permanent magnet. Changeable flux is created by a variable current flowing through coil such the solenoid. The direction of this flux is changed due to current flowing through coils. The combination of permanent and changeable fluxes make various flux densities between yokes of moving part and fixed yokes. And then, the flux densities create forces(F), which are used to drive this actuator, in lower and upper gap. In this actuator ...

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.183-186
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• 1997

This paper presents the new MR rotary brake with a permanent magnet, based on the shear operating mode. Due to the permanent magnet, the MR rotary brake can give the nominal resistance to the external disturbance and give the fail safe capacity to the system even when the power supply is accidentally cut off. As we apply the positive or negative current to the electric magnet coil, the resistance torque of the MR rotary brake can be reduced to the value less than the nominal resistance or increased up to the magnetic saturation point.