• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.4
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• pp.49-55
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• 2014

In this paper, we propose the cogging toque reduction technique of the dual stator radial flux permanent magnet generator. The cogging toque is caused by the torque ripple increase and vibration and noise of the generator. And it is important factor determining cut-in speed of the small wind generator. To reduce cogging torque, permanent magnet displacement was studied. And the theory of the permanent magnet displacement was formulated and the cogging torque reduction according to the permanent magnet displacement was confirmed through the finite element method.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1596-1603
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• 2018

This paper presents the new design and validation process of the linear transverse flux machine of the stelzer machine for hybrid vehicle application. A linear transverse flux machine is a novel electric machine that has higher force density and power than conventional electric machine. The process concentrates on 2-dimensional and 3-dimensional analysis using equivalent magnetic circuit method considering leakage elements and it is verified by finite element analysis. Besides the force characteristics of all axis of each direction are analyzed. The study is considered by dividing the transverse flux electric excited type and the transverse flux permanent magnet excited type. Additionally three-dimensional analysis in this machine is accomplished due to asymmetric structure with another three axes. Finally, it suggests the new design and validation process of linear transverse flux machine for stelzer machine.

• Agricultural and Biosystems Engineering
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• v.1 no.1
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• pp.49-53
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• 2000

A magnet assembly is a critical element of a nuclear magnetic resonance(NMR) based sensor. Magnetic flux density and homogeneity are essential to its optimum performance. Geometry and magnet material properties determine the magnetic flux density and homogeneity of the assembly. This study was carried out to develop the design for a magnet assembly. A 2-D finite element model for the magnetic assembly was developed using ANSYS and evaluated the effects of adding shimming frames and steel bars in the corners of the rectangular steel cover which surrounded the magnet. The assembly was manufactured and evaluated. According to the ANSYS model, modified pole frames increased magnetic flux density by 8.3% and increased homogeneity by 83%. Addition of steel bars in the corners increased the magnetic flux density by 1%, and improved homogeneity up to three times. The difference between simulated and measured magnetic flux densities at the center point of the air gap was within 2.4%.

• Journal of Magnetics
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• v.18 no.3
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• pp.297-301
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• 2013

Flux-reversal machine (FRM) is cost effective and suitable for mass production due to its simple structure. However, there is a notable permanent magnet flux leakage which deteriorates the performance. To compensate this drawback with a design method, an Inset-Permanent-Magnet-Type FRM (ITFRM) has been proposed. The ITFRM has permanent magnets perpendicular to the stator teeth surface, and thus, is much more difficult to demagnetize. In this paper, we deal with the iron losses and irreversible permanent magnet demagnetization characteristics of the ITFRM according to various design variables and driving conditions. To analyze the characteristics, a two-dimensional finite-element method (2D-FEM) considering nonlinear analysis of permanent magnets is used. As a result, we propose the design variables that have the largest effects on the iron losses and irreversible magnet demagnetization.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.722-727
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• 2010

This paper presents Dynamic-Simulation to estimate the inductance of a permanent magnet type transverse flux rotating motor by applying the real-time parameter estimation theory. As transverse flux rotating motor has the complex structure, it can be happen to some errors between real value and designed one with respect to the inductance. To reduce this kinds of errors, the real-time parameter estimation theory was applied to dynamic-simulation. And then, By comparing the estimated inductance and designed one, it is realized that the real-time parameter estimation theory can be applied in the permanent magnet type transverse flux rotating motor.

• 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 ...

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1954-1959
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• 2014

This paper attempts to design and present a comparison of classical Direct Torque Flux Control (DTFC) for Line-Start Permanent Magnet Synchronous Motor (LSPMSM) and its equal Permanent Magnet Synchronous Motor (PMSM). In order to present an in-depth analysis, both motors for DTFC Voltage Source Inverter (VSI)-fed in the same situations of different conditions are simulated and tested. The advantages of the proposed method for LSPMSM over the PMSM are discussed and analyzed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.769-772
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• 2016

In this paper, the overhang structure was applied to the axial flux permanent magnet (AFPM) motor. This paper describes the overhang effect in the AFPM motor. Moreover, the overhang effect was analyzed according to the different overhang length and an optimal overhang structure was proposed. Finally, the proposed structure was applied to design, analysis and experiment of prototype motors. Through the comparison between 3D finite element analysis results and experimental ones, the validity of proposed structure is clarified.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.3
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• pp.143-151
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• 2004

High-speed permanent magnet machines are likely to be a key technology for electric drives and motion control systems for many applications, since they are conductive to high efficiency, high power density, small size and low weight. In high-speed machines, the permanent magnets are often contained within a retaining sleeve. However, the sleeve and the magnets are exposed to high order flux harmonics, which cause parasitic eddy current losses. Rotor losses of high-speed machines are of great importance especially in high-speed applications, because losses heat the rotor, which is often very compact construction and thereby difficult to cool. This causes a danger of demagnetization of the NdFeB permanent magnets. Therefore, special attention should be paid to the prediction of the rotor losses. This paper is concerned with the rotor losses in permanent magnet high-speed machines that are caused by permeance variation due to stator slotting. First, the flux harmonics are determined by double Fourier analysis of the normal flux density data over the rotor surface. And then, the rectilinear model was used to calculate rotor losses in permanent magnet machines. Finally, Poynting vector have been used to investigate the rotor eddy current losses of high-speed Permanent magnet machine.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.24-27
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• 1999

This paper proposed a method to reduce torque ripple of double-layer axial flux permanent magnet motor. Torque is generated by interacting between current of stator winding and airgap flux. In the case of slotless axial flux permanent magnet motor, only commutation torque component is significant. Hence, cogging and reluctance torque will not be considered. For this propose, we were supplied differential phase current in each winding and shifted rotor magnet. According to shifted rotor magnet and flux and phase of current were shifted, phase of developed torque in each side is difference. As a result, we could reduce the total torque ripple in motor and obtain minimum torque ripple in the case of 7.5 degree shifting angle between two rotors.