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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.

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.

Won H.,Korea Marine Equipment Research Institute | Ju H.,Pusan National University | Park S.,Pusan National University | Park G.S.,Pusan National University
IEEE Transactions on Magnetics | Year: 2013

In this paper, a study on the demagnetization of ferromagnetic materials is conducted based on both experiments with magnetic treatment facility (MTF), which is a miniaturized experimental model, and numerical analysis methods in which the static magnetic finite-element method and Preisach model are combined. The magnetic hysteresis phenomenon inside ferromagnetic materials is effectively mimicked by means of Preisach model. However, owing to the use of M-H variables, Preisach model generally bears numerical instability during repetitive computations. A Preisach model with M-B variables is proposed in this paper to resolve the numerical instability. From the proposed Preisach model with M-B variables, analysis results that were tantamount to those from the general Preisach model with M-H variables were obtained. Numerical instability was also resolved by the proposed model. Furthermore, the discrepancy was practically negligible between the experimental result from a practical demagnetization process and the numerical analysis result from the proposed Preisach model with M-B variables, under the same conditions. © 1965-2012 IEEE.

Choi J.-H.,Korea Marine Equipment Research Institute | Choi S.-H.,Kangwon National University
International Journal of Engineering Systems Modelling and Simulation | Year: 2014

The 100-seater totally enclosed lifeboat is an essential safety equipment to escape in offshore structure. Therefore, structured safety assessment for lifeboat must be made essentially to operate normally in case of emergency. In this paper, the structural strength analysis is performed for a variety of conditions when the 100-seater totally enclosed lifeboat is installed on the hook of davits. The 100-seater totally enclosed lifeboat study has been performed using the software ANSYS ver. 13.0, FE analysis programme. By using the software ANSYS programme in the shipbuilding industry, it will contribute to technology development and productivity of the 100-seater totally enclosed lifeboat. Also through the simulation and analysis code, it will contribute greatly to the development of IT. Copyright © 2014 Inderscience Enterprises Ltd.

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.

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