• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.304-315
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• 2013

In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.3
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• pp.139-146
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• 2019

As the number of electric vehicles (EVs) in Jejudo Island increases, the secondary use of EV batteries is becoming increasingly mandatory not only in reducing greenhouse gas emissions but also in promoting resource conservation. For the secondary use of EV batteries, their capacity and performance at the end of automotive service should be evaluated properly. In this study, the battery state information from the on-board diagnostics or OBD2 port was acquired in real time while driving three distinct routes in Jejudo Island, and then the battery operating characteristics were assessed with the driving routes. The route with higher altitude led to higher current output, i.e., higher C-rate, which would reportedly deteriorate state of health (SOH) faster. In addition, the SOH obtained from the battery management system (BMS) of a 2017 Kia Soul EV with a mileage of 55,000 km was 100.2%, which was unexpectedly high. This finding was confirmed by the SOH estimation based on the ratio of the current integral to the change in state of charge. The SOH larger than 100% can be attributed to the rated capacity that was lower than the nominal capacity in EV application. Therefore, considering the driving environment and understanding the SOH estimation process will be beneficial and necessary in evaluating the capacity and performance of retired batteries for post-vehicle applications.

• Journal of Distribution Science
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• v.13 no.6
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• pp.79-86
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• 2015

Purpose - The cosmetics industry is a traditional high value-added industry in terms of the domestic demand, small batch production systems, exclusive competition, and raw materials highly dependent on overseas countries as well as an oligopolistic market structure. However, new foreign brands and growing consumer awareness of inexpensive products, has triggered a shift. In line with changing lifestyles and the polarization of consumption, the industry faces a new market structure. Among its key characteristics is the cosmetics industry's numerous distribution channels (i.e., department stores, door-to-door sales, online shopping malls, brand shops, and discount stores). Therefore, the study of its distribution channels is essential. Research design, data, and methodology - The study analyzed channel distribution power divided into coercive and non-coercive power. The factors of coercive power included: unilateral request of an increase in commissions, interference in sales by taking advantage of a superior status, unilateral buck-passing at the time of a problem, unilateral request to stop sales activities, and a unilateral business contract; the factors of non-coercive power included favorable payment conditions, offers of various kinds of information, policy on commission reduction, pride in market entrance, and promotion support. In addition, the mediating variable "interdependence" was applied to the execution of department store (or mart) power and their shop conflicts and satisfaction to examine direct and indirect influential power. The methodology was a survey of managers of cosmetics shops in department stores (or marts). The questionnaire, based on a five-point Likert scale, included questions about basic personal information, execution of power, interdependence, conflict, and satisfaction. The study distributed 198 questionnaires and collected 131. Ten questionnaires with missing or hard to analyze data were excluded. Thus, 121 copies were analyzed. Results - According to the analysis, the execution of coercive power by department stores (or marts) did not affect interdependence, but the execution of non-coercive power did. Interdependence did not influence conflict, but did affect satisfaction. Additionally, the analysis revealed direct influential power: the execution of coercive power positively affected conflict and negatively influenced satisfaction; the execution of non-coercive power positively affected satisfaction. Conclusions - To offer suggestions for distribution business relations in the cosmetics industry, this study investigated how the execution of power by department stores (or marts) affected their shops. More specifically, it examined how much the execution of both coercive power and non-coercive power influenced conflict and satisfaction, and analyzed the mediating role of interdependence. In line with previous study results in various areas, coercive power was shown to be the source of conflict, leading to a decrease in satisfaction, whereas non-coercive power significantly positively influenced satisfaction. Moreover, non-coercive power increased interdependence, which led to greater satisfaction. As a result, interdependence had a mediating effect on non-coercive power and satisfaction. Based on the results, department stores (or marts) should look for improvements plans that increase interdependence. Such plans could alleviate conflict with the shops, increasing their satisfaction.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.337-350
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• 1999

Thick diamond film having ~700${\mu}{\textrm}{m}$ thickness was deposited on polycrystalline molybdenum (Mo) substrate using high power (4kW) microwave plasma enhanced chemical vapor deposition (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconductivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.441-445
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• 1999

Thick diamond film having $~700\mu\textrm{m}$ thickness was deposited on polycrystalline molybdenum(Mo) substrate using high power (4 kW) microwave plasma-enhanced chemical vapor depostion (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconcuctivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• Geomechanics and Engineering
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• v.23 no.4
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• pp.381-392
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• 2020

The difficulties, challenges and limitations faced in standard pressuremeter testing in the measurement of low soil deformations led a number of researchers to think about the possible modification of the equipment, and especially the replacement of the volumeter by a Hall Effect sensor. This article is a major contribution in this direction. It makes an attempt to detail the design, manufacture and operation of the new equipment. The calibration of the various components was carried out according to the rules presently in force. This proposal was applied, on an exploratory basis, to the data of a real site located in France. The authors present the preliminary results of some cyclic pressuremeter tests, previously carried out in the laboratory, on a sandy material, and they then provide a basic interpretation of these results. The findings indicated that the proposed apparatus is capable of providing high-quality information about constraints and deformations. Although these tests were performed within the laboratory, it was possible to analyze the power, quality, performance and insufficiencies of the proposed equipment.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.745-749
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• 2003

The iterative sliding mode observer is proposed to control sensorless PMSM(Permanent Magnet Synchronous Motor). Proposed sliding mode observer has the character which is robust to the disturbance and parameter variation. Low pass filter with the variable cutoff frequency is also proposed to compensate rotor angle, it is led to saving memory and minimizing operation time. Experimental results shows that the proposed sliding mode observer leads to the proper performance.

• Journal of Welding and Joining
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• v.31 no.3
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• pp.11-16
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• 2013

Through-silicon-via (TSV) is a major technology in microelectronics for three dimensional high density packaging. The 3-dimensional TSV technology is applied to CMOS sensors, MEMS, HB-LED modules, stacked memories, power and analog, SIP and so on which can be employed to car electronics. The copper electroplating is widely used in the TSV filling process. In this paper, the various Cu filling methods using the control of the plating process were described in detail including recent studies. Via filling behavior by each method was also introduced.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1825-1842
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• 2013

Rapid growth of the IT industry has led to significant energy consumption in the last decade. Data centers swallow an enormous amount of electrical energy and have high operating costs and carbon dioxide excretions. In response to this, the dynamic consolidation of virtual machines (VMs) allows for efficient resource management and reduces power consumption through the live migration of VMs in the hosts. Moreover, each client typically has a service level agreement (SLA), this leads to stipulations in dealing with energy-performance trade-offs, as aggressive consolidation may lead to performance degradation beyond the negotiation. In this paper we propose a heuristic based resource allocation of VM selection and a VM allocation approach that aims to minimize the total energy consumption and operating costs while meeting the client-level SLA. Our experiment results demonstrate significant enhancements in cloud providers' profit and energy savings while improving the SLA at a certain level.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1150-1152
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• 1998

Recently, our electric industry confronts a structural change and high competiveness environment in the course of deregulation. Rapid growth in electricity demand, financial need for new power plant construction, and envionmental problems have led to search for more efficient energy production and energy conservation techmologies. Especially, residential and commercial buildings consumes 40% of electricity demands and building energies are increasing more and more in Korea. The purpose of this paper is to analyze the electricity use of commercial buildings by end-use. Also, we will use it as a basic informations of DSM potential evaluation and evaluation process based on different approach by sector and type of potential.