• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.3
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• pp.1-11
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• 1997

This study aims to estimate the relative importance of quality management items through the defect analysis in the landscape construction process. The RIQMI are decided by the defect coefficient and it's cause weight. The defect items in the landscape construction process were classified by 56 items based on the classification form of '96 landscape architectural construction standard and the cause pattern were categorized 4 types as design, material, construction, and environment factors. To analyze the defect coefficient and the aucse weight by defect, the researcher surveyed the questionnaires on the 103 engineers and the 31 experts on the landscape architectural construction. The result of this study are as follows. The relative importance by facilities pattern turn out to be much higher construction, material fator than design. environment factor in wood facilities, paving facilities, and steel facilities, the RIQMI is very high in timber crack, timber vending, faulty of timber against decay, welding faulty of steel facilities in material factor, and timber crack, faulty of timber against decay, finish faulty of steel facilities, welding faulty of steel facilities in construction factor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.18-28
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• 2009

To analyze influences under faults caused by a stator winding short and to evaluate an effectiveness of a diagnostic algorithm a faulty model for an inverter-driven permanent magnet synchronous motor is presented. Even though the conventional dq motor model obtained through the transformation of phase voltage model is widely used to analyze and control the motor, it can not be used in the analysis of a faulty motor since the 3-phase balanced condition is no longer hold under the fault caused by a stator winding short, and thus, it is very difficult to obtain motor input voltages from the pole voltage of an inverter. To overcome this problem, a faulty model for an inverter-driven permanent magnet synchronous motor is proposed by considering the line voltage of 3-phase variables. The effectiveness of the proposed faulty model is verified through comparative simulations and experiments using DSP TMS320F28335 and motor built to allow a partial short of inter-turn.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.6
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• pp.570-576
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• 2006

This paper describes a method for the detection of shorted-turn in the cylindrical synchronous generator rotor windings based on the discrete wavelet transform. Multi-resolution analysis(MRA) based on discrete wavelet transform provides a set of decomposed signals in independent frequency bands, which contain independent dynamic information due to the orthogonality of wavelet function. In the proposed method, shorted-turn detection in rotor windings is based on the decomposition of the rotor currents, where wavelet coefficients of these signals have been extracted. Comparing these extracted coefficients is used for diagnosing the healthy machine from faulty machine. Experimental results are presented for healthy, and machines with 25%, 42%, 67%, 83%, 99% inter-turn short circuits in a rotor slot. Deviation of wavelet coefficients in healthy mode from faulty modes depicts the inverse proportion of shorted-turns. Experimental results show the effectiveness of the proposed method for shorted-turn detection in the cylindrical synchronous generator rotor windings.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.23-30
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• 2013

This paper proposes a parametric model for inter-turn fault detection in a fault-tolerant permanent-magnet (FTPM) machine, which can predict the effect of the short-circuit fault to various physical quantity of the machine. For different faulty operations, a new effective stator inter-turn fault detection method is proposed. Finally, simulations of vector-controlled FTPM machine drives are given to verify the feasibility of the proposed method, showing that even single-coil short-circuit fault could be exactly detected.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.476-478
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• 2005

This paper describes a method for the detection of shorted-turn in the cylindrical synchronous generator rotor windings based on the discrete wavelet transform. Multi-resolution analysis(MRA) based on discrete wavelet transform provides a set of decomposed signals in independent frequency bands. In the proposed method, shorted-turn detection in rotor windings is based on the decomposition of the rotor currents, where wavelet coefficients of these signals have been extracted. Comparing these extracted coefficients is used for diagnosing the healthy machine from faulty machine. Experimental results show the effectiveness of the proposed method for shorted-turn detection in the cylindrical synchronous generator rotor windings.

• Journal of the Korean Solar Energy Society
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• v.33 no.4
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• pp.89-93
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• 2013

In recent years, many investigations about photovoltaic power systems have been significantly carried out in the fields of renewable power energy. Such research area generally includes developments of highly efficient solar cells, advanced power conversion systems, and smart monitoring systems. A generic objective of fault detection and diagnosis techniques is to timely recognize unexpected faulty of dynamic systems so that economic demage occurred by such faulty is decreased by means of engineering techniques. This paper presents a novel fault detection approach for photovoltaic power arrays which are electrically connected in series and parallels. In the proposed fault detection scheme, we first measure all of photovoltaic modules located in each array by using electronic sense systems and then compare each measurement in turn to detect location of fault module through statistic computation algorithm. We accomplish real-time experiments to demonstrate our proposed fault detection methodology by using a test-bed system including two 20 watt photovoltaic modules.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.88-96
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• 2016

In this paper, the GaN FET based phase-shift full-bridge dc-dc converter design is implemented. Switch characteristics of GaN FET were analyzed in detail by comparing state-of-the-art Si MOSFET. Owing to the low conduction resistance and parasitic capacitance, it is expected to GaN FET based power conversion system has improved performance. However, GaN FET is vulnerable to electric interference due to the relatively low threshold voltage and fast switching transient. Therefore, it is necessary to consider PCB layout to design GaN FET based power system because PCB layout is the main reason of stray inductance. To reduce the electric noise, gate voltage of GaN FET is analyzed according to operation mode of phase-shift full-bridge dc-dc converter. Two 600W phase-shifted full-bridge dc-dc converter are designed based on the result to evaluate effects of stray inductance.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.219-224
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• 2020

The purpose of this study is to develop a device to replace the pre-boring method, which is generally constructed, to prevent pile damage caused by tension cracks that reason from tension waves generated during PHC pile construction on soft ground. Tension cracks are caused by tension waves from the hammer striking during the PHC pile hitting on the soft ground, which in turn leads to faulty construction. In order to prevent the occurrence of tension waves generated during driving, apply separate driving force increasing device to prevent the generation of tension waves, and pile damage as well. Also, it is an eco-friendly construction method that reduces smoke and noise by improving construction speed, reducing construction costs, and able to small equipment when developing equipment. This development equipment is a piece of effective equipment that can pioneer the Saemangeum reclamation area, the South-east Asian construction market, where the Deep soft ground is distributed.