Korea Marine Equipment Research Institute

Busan, South Korea

Korea Marine Equipment Research Institute

Busan, South Korea
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Kim K.-T.,University of Ulsan | Hur J.,University of Ulsan | Kang G.-H.,Korea Marine Equipment Research Institute
8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia | Year: 2011

We performed circulating modeling before the studying inter turn fault. It used a finite element method (FEM)-based model to consider the magnetic non-linearity. By integrating the developed model with a current-controlled voltage source inverter (CCVSI) model, the distributed characteristics of an inter-turn fault operated by six-switched inverter are investigated considering the speed control. Also, this paper presents flux density distribution and torque characteristic to analyze the inter turn fault of interior permanent magnet (IPM) type BLDC motor having inter-turn fault. Also, we proposed new fault impedance modeling for magnetic characteristics analysis. The fault impedance is required to calculate the circulating current that causes magnetic distortion. Thus, this paper proposes a method for estimation of the circulating current taking into account the voltage at the shorted turn and the rotating speed. The analysis data were verified experimentally. © 2011 IEEE.


Lee S.-K.,Korea Marine Equipment Research Institute | Kang G.-H.,Korea Marine Equipment Research Institute | Hur J.,University of Ulsan
8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia | Year: 2011

The purpose of this paper is to provide the radial force and vibration mode comparison between two large interior permanent magnet machines (IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonics according to eccentricity condition such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide a clue what eccentricity condition occurs in the machine. © 2011 IEEE.


Park H.K.,Chonnam National University | Kim H.,Korea Marine Equipment Research Institute
Construction and Building Materials | Year: 2015

Windows are used not only for lighting and thermal insulation, but also for sound attenuation. Most window frames installed in apartments are composed of either aluminum or polyvinylchloride. In general, windows in Korea consist of an outer frame forming the opening and a window frame attached to the glass, with enough clearance at the top and bottom to join them together. This space at the top and the bottom for the sliding type is the main factor affecting thermal and acoustic performance. In addition, the precision of the fit between the frames and deterioration of the mohair attached to the window frame affect environmental performance. There is however somewhat gap because the inner frame should be installed within the outer frame in the field. The goal of this study is to improve environmental conditions in residences by increasing the airtightness of windows to counteract deterioration of performance due to aging window frames and mohair. The results indicate that these attachments can attenuate sound effectively and can be regarded to reduce energy and natural resource use by attaching them to deteriorated windows or in apartments needed to be reinforced. © 2015 Elsevier Ltd. All rights reserved.


Son Y.-D.,Dongseo University | Kang G.-H.,Korea Marine Equipment Research Institute
Journal of Electrical Engineering and Technology | Year: 2010

This paper presents the implementation and characteristic analysis of a drive system for a three-phase permanent magnet motor with independent excitation winding that is applicable for electric bicycles. The design features improves the phase current waveform, output power, and torque by using advance angle control. This adjusts the phase angle of each phase current in relation to back EMF. In addition, a DC-side PI current control is performed through PWM generation circuit using a low-cost one-chip microcontroller and a CPLD chip, resulting in reduced system costs. Finally, the validity of this control scheme for driving electric bicycles and output/torque improvement characteristics are verified through analysis and experimental results.


Kim H.-K.,University of Ulsan | Jin-Hur,University of Ulsan | Kim B.-W.,University of Ulsan | Kan G.-H.,Korea Marine Equipment Research Institute
2010 IEEE Energy Conversion Congress and Exposition, ECCE 2010 - Proceedings | Year: 2010

A stator turn fault in a symmetrical three-phase machine cause a large circulating current to flow and subsequently generated excessive heat in shorted turns, generate irregular control current of the three phase leads to demagnetization. The demagnetization of PM occurred distortion of air-gap magnetic flux distribution caused deterioration of their torque, mechanical vibration etc. In this paper, for minimization of mechanical vibration, the optimal PM shape is designed and the effect of the circulating current in shorted turns on the demagnetization of PM and motor performance is analyzed. For this analysis, this paper developed a FE-based simulation model with a stator turn fault modeling. The demagnetization phenomenon in IPM type BLDC is analyzed under continuously controlled 3-phase input current considering the circulating current in shorted turn using the developed transient analysis method. © 2010 IEEE.


Lee S.-K.,Korea Marine Equipment Research Institute | Lee S.-K.,University of Ulsan | Kang G.-H.,Korea Marine Equipment Research Institute | Hur J.,University of Ulsan | Kim B.-W.,University of Ulsan
IEEE Transactions on Magnetics | Year: 2014

This paper deals with the reduction of torque pulsation including torque ripple and cogging torque in surface PM brushless ac motors. The fractional combination and air-gap shape design by shaping the PM and stator core are studied to reduce torque pulsation. Torque ripple reduction is achieved by adjusting the magnetic flux density in air-gap contour by cutting magnet outer shape. Quasi-zero torque pulsation in this paper means the ripple ratio to average torque < 0.5\%. The magnetic field and torque characteristics are analyzed by 2-D finite element analysis and prototype to validate is manufactured and measured. © 2014 IEEE.


Hur J.,University of Ulsan | Reu J.-W.,LG Corp | Kim B.-W.,University of Ulsan | Kang G.-H.,Korea Marine Equipment Research Institute
IEEE Transactions on Industry Applications | Year: 2011

This paper proposes a harmonic elimination method for vibration and noise minimization of an interior-type permanent-magnet motor, achieved by alternating the distribution of the radial flux density. The minimization of vibration and noise is realized by forming optimal notches corresponding to the shape of the magnetic field on the rotor pole face. The variations in vibration are computed by a nonlinear finite element method, and the validity of the analysis and rotor shape design is confirmed by performing vibration and performance experiments. © 2011 IEEE.


Lee S.-K.,Korea Marine Equipment Research Institute | Lee S.-K.,University of Ulsan | Kang G.-H.,Korea Marine Equipment Research Institute | Hur J.,University of Ulsan | Kim B.-W.,University of Ulsan
IEEE Transactions on Magnetics | Year: 2012

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results. © 1965-2012 IEEE.


Cho Y.-U.,Korea Marine Equipment Research Institute | Kang G.-H.,Korea Marine Equipment Research Institute
2016 IEEE Transportation Electrification Conference and Expo, Asia-Pacific, ITEC Asia-Pacific 2016 | Year: 2016

This paper presents one of the methods for estimation of the electromagnetic excitation force of the motor. In order to identify the excitation force of the motor, vibration data was obtained using phase reference spectrum to overcome a number of channels of the DAQ instrument. FE model of the 200kW motor was made to calculate the transfer function from FEM analysis. Impact test was carried out and compared impact test results with FEM analysis results to verify the FE model of 200kW motor. The singular value decomposition was used to reduce calculation errors of the force identification, and pseudo inverse used to solve the matrix inverse problem. This equivalent excitation force is useful to design 200kW motor. © 2016 IEEE.


Lee C.Y.,Chung - Ang University | Bae J.-H.,Chung - Ang University | Kim T.-Y.,Korea Marine Equipment Research Institute | Chang S.-H.,Chung - Ang University | Kim S.Y.,Chung - Ang University
Composites Part A: Applied Science and Manufacturing | Year: 2015

Silane-functionalized graphene oxides (sGOs) were fabricated with four different self-assembled monolayers (SAMs) to reinforce an epoxy adhesive, with the aim of improving the bonding strength of carbon/epoxy composites. The oxygen-containing groups on the surface of graphene oxide (GO) were converted by the SAMs to amine, epoxy, or alkyl groups. The successful reaction between the silane molecules of the SAMs and functional groups of GO was evidenced by the results of different characterization methods such as Fourier transform infrared spectroscopy. It was found that the average thickness of the sGO flakes was higher than that of GO flakes. The bonding strength of a carbon fiber/epoxy composite, tested with a single lap joint bonded with an epoxy adhesive, was increased by 53% after the addition of a sGO that contained amine groups. These results show that sGOs, especially those containing amine functional groups, can strengthen the interfacial bonding between the carbon fibers and epoxy adhesive. © 2015 Elsevier Ltd. All rights reserved.

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