• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.113-115
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• 2003

Recently, many linear motion generators and are rapidly finding applications that ranges from short stroke linear motion vibrators, such as dynamic cone type loud speakers tostirling engine driven linear reciprocatings, alternators, compressors, textile machines etc. In this paper the dynamic performance with load is computed by a general purpose method, which the equation of electromagnetic field, the equation of electric circuit and the equation of motion are coupled together. We fumed out the driving system and the dynamic characteristics of current, voltage and displacement is confirmed experiment.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.563-566
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• 1992

Recently, a lot of efforts have been made to satisfy noise and vibration performance requirements of rotating electric precision machines by the use of various numerical techniques. This paper looks into the enfluence of the magnetization pattern and the shape of air gap which play the role of primary variables of the electro-magnetic circuits, and finally, an experimental verification has been performed to illustrate the efficiency and the advantages or the optimal air gap shape minimizing the cogging torque.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2329-2334
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• 2018

This paper discusses the thermal effect of the number of permanent-magnet (PM) layers in an outer rotor machine. Depending on the number of axial-layer of PM, the operating temperature is compared analytically and experimentally. The electromagnetic analysis is performed using 3-dimensional time varying finite element method to get the heat sources depending on axial-layered PM models. Then thermal analysis is conducted using the lumped-parameter-thermal-network method for each case. Two outer rotor machines, which have the different number of axial-layer of PM, are manufactured and tested to validate the analysis results.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.161-171
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• 2002

This paper presents a linear motor, which generates large thrust with a low operating rate. In industrial fields there is a need for actuators that work with a low duty cycle but generate large thrusts. An example of such a case is provided by the actuators for ejector mechanisms in electric injection molding machines. The ordinary LSM (linear synchronous motor) is unsuitable for this large-thrust and low-operating-rate usage, because of its large size and high cost. This paper contains experimental results on linear motors that can generate large thrusts for a short time, and which can be cheaply produced. The described linear motor could be contained space of $250mm \times250mm\times 250mm$ and generate a maximum thrust of about 20000 N at a current of 250 A.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.555-566
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• 2012

This paper presents a thermal analysis of an interior PM synchronous machine with concentrated winding for electric vehicle. The conventional thermal equivalent network model has been used for a long time for calculation of the temperature rises in electrical machines. In spite of being popular, this method can not be applied correctly for elements with complicated cooling structure like liquid cooled housing. To overcome this drawbacks, in this paper, a hybrid thermal model using the result of CFD analysis partly. Using this method, to improve a thermal performance of PMSM with concentrated winding, the effects of two design parameters are analysed. Finally, the accuracy of this model has been verified by experiments for the developed 21kW motor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1434-1446
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• 2018

This paper presents new speed control strategy for periodic load torque injected in AC motor. If motor drive system has a periodic load torque, it causes a periodic motor speed ripple bringing about vibrations and noises. This paper proposed new control method consisting of PIR(proportional-integral-resonant) controller and repetitive controller. PIR controller controls DC, low frequency and fundamental components and repetitive controller controls other harmonics. The performance has been verified through computer simulations using MATLAB Simulink and experiments.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.33-38
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• 2010

Railway is one of popular transportation systems. Due to the safety and in time, the transportation by train is preferred to the others for a long time. However, accidents under railway construction get more serious problems than in case of the other system, because it is the largest mass transportation system. Especially, the railway construction is composed of different kinds of construction works such as civil, architect, electric and mechanic. It is closely/complicatedly connected with various workers, large machines and facilities, regulations etc. In this study the data on safety accidents are corrected during 6 years(2004~2009) and analyzed by time(year, month, week, day, a.m or p.m), place, field, type etc. Results shows that there exists remakable trends on accidents, so efficient treatments should be prepared considering this trend.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.28-36
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• 2008

This paper presents a novel prototype of zero current switching pulse frequency modulation (ZCS-PFM )high frequency series resonant inverter using IGBT power module for electromagnetic induction eddy current heated roller in copy and printing machines. The operating principle and unique features of this voltage-fed half bridge inverter with two additional soft commutation inductor snubber are presented including the transformer modeling of induction heated rolling drum. This soft switching inverter can achieve stable zero current soft commutation under a discontinuous and continuous resonant load current for a widely specified power regulation processing. The experimental results and computer-aided analysis of this inverter are discussed from a practical point of view.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.206-211
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• 2008

Noise sources in electric machines are broadly categorized as magnetic, mechanical, electronic and aerodynamic. Especially, there are several kinds of noise sources due to the change of reluctance by rotor position in IPM motor. To separate acoustic noise by mechanical structure and electromagnetic sources, resonance frequency and the effect of vibration and acoustic noise by electromagnetic sources are analyzed. And then, the structural and electromagnetic designs to reduce acoustic noise are performed. The relevance about the study on noise reduction of IPM motor is verified by noise experiment, noise and vibration analysis.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.4
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• pp.203-208
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• 2006

This paper presents characteristics of SynRM(Synchronous Reluctance Motor) that is compared with a high speed induction motor. SynRM is much suitable for high speed electric machines because of structural robustness. There are many kinds of SynRM according to the shape of rotors. Particularly, axially laminated anisotropic (ALA) rotor is suitable for high speed instruments. Characteristics of SynRM with ALA rotor is obtained from a governing voltage and torque equation mainly composed of d-axis and q-axis inductance that will be identified with finite element method.