• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.406-408
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• 2005

In this literature, when the utility line is normal, the Off-Line UPS operates as an active power filter to compensate the reactive power from a load, and when the utility line is in outage, the On-Line UPS opuates as in single phase inverter to supply an active and reactive power to the load. An additional static switch in UPS was used to decrease an transient state during these mode changes. And the result shows that the transient state disappeared.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.60-68
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• 2010

Recently, Power Conditioning System (PCS) tends to require more compact, higher efficiency and power density with better performance. A novel topology consisted of LLC resonant inverter and Low Frequency (LF) cyclo-converter for connecting to utility line is able to meet these requirements. The technical operating analysis is described and 1kW prototype is tested and verified the performances through connecting the 110Vac 60Hz utility line. Efficient results are described.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1251-1264
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• 2018

The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.116-119
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• 2004

The existing monitoring and control systems of utility-pipe conduit (power tunnel, cable tunnel etc) have established communication lines using optical fiber, leaky coaxial cable (LCX), and several kinds of control cable. Due to the properties of the used media, the cost of equipment is considerably high and the maintenance of the system is difficult. Also, the term of carrying out is long so that the extension of the system is in difficulty. Now it is desirable to adopt Power Line Communication (hereinafter, PLC) technology in the monitoring and control systems and use the existing low-voltage power-line for lamplight as communication line. This will lead the reduction of the construction cost and the easy maintenance of the system. In this paper, we research the characteristics of PLC in conduit, design and manufacture the field test system, and analyze the performance of the system by field test. Then, we introduce the reliable monitoring and control system of utility-pipe conduit using PLC.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.5
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• pp.278-285
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• 1999

This paper proposes new 12 and 24-pulse rectifier systems using an open-delta auto-connected transformer. This approach employs two static converters to operate it at higher than utility line frequencies and to provide multi-pulse operation. By operating magnetic components at a higher frequency, higher power density can be achieved. A unique feature of the proposed approach is that the magnetic components for the dc-side are also exposed to a higher frequency and these components too are reduced in size. The switching frequency and its harmonic components are absent in the utility input line current. The VA ratings of the transformer and static converter are 0.236/0.292 [pu] and 0.11/0.18 [pu] in 12 and 24-pulse rectifier system, respectively. A finer grade of steel or alternatives can be deployed to increase performance and reduce size further. Analysis, simulations, simulations, design example, and experimental results for a 480[V], 10{kVA] prototype system are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.536-543
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• 2000

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three-phase inverter is used for the connection between the photovoltaic array and the utility. This paper present a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL Control system and the Phase detector of Interactive Voltage by using dq transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.103-106
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• 2002

This paper has studied a remote AMR(Automatic Meter Reading) system using the power line and the telephone line as a communication media and the digital power meter. In the developed system, because we have used the power line and telephone, the facility is very easy and then its cost is not expensive. The system includes following elements: a digital power meter, an indoor communication system using a power line modem and a telephone line interface system for sending data to the utility company.

• Transactions of Materials Processing
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• v.9 no.5
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• pp.512-525
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• 2000

Designers are frequently faced with multiple quality issues in injection molded parts. These issues are usually In conflict with each other, and thus tradeoff needs to be made to reach a final compromised solutions. The objective of this study is to develop an automated injection molding design methodology, whereby part defects such as warpage and weld line are optimized. The features of the proposed methodology are as follows: first, Utility Function approach is applied to transform the original multiple objective problem into single objective problem. Second is an implementation of a direct search-based Injection molding optimization procedure with automated consideration of process variation. The Space Reduction Method based on Taguchi's DOE(Design Of Experiment) is used as a general optimization tool in this study. The computational experimental verification of the methodology was partially carried out for a can model of Cavallero Plastics Incorporation, U. S. A. Applied to production, this study will be of immense value to companies in reducing the product development time and enhancing the product quality.

• Journal of Distribution Science
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• v.16 no.12
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• pp.57-68
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• 2018

Purpose - The development of technologies lead the volume of sale on online market increase but an off-line shopping center is still a core component in the omni-channel strategy. It is generally thought that high-level retailtainment on brick and mortar store affects purchase intentions positively, but some previous studies dispute that and have reported that retailtainment does not affect purchase intentions. So we have studied the additional factors' effect - the nature of purchase and utility - with retailtainment. Research design, data, and methodology - There are 8 treatment groups which were assigned by the method of retailtainment (high vs. low), nature of purchase (essential vs. non-essential), and utility (acquisition vs. transaction). A total of 240 subjects (office workers = 163, 68%; undergraduates = 77, 32%; average age = 30s; female = 39%) were divided into groups and exposed to one of the eight scenarios. Participant's purchase intention was the dependent, and ANOVA and L-matrix were used to analyze for main and interactive effects between factors. Results - First, the main effect and interactive effect between retailtainment and the nature of purchase are significant. We also found that the contrast between essential and non-essential at low-level retailtainment is higher than that of high-level retailtainment. Second, in the case of retailtainment and utility, transaction utility under high-level retailtainment affects purchase intentions positively. Third, between the nature of the purchase and utility, the main effect of the nature of purchase and the interactive effect is significant, but the main effect of utility is not significant. In the case of non-essential goods, the purchase intention was high when transaction utility was provided but in the case of essential goods, acquisition utility increased purchase intentions. Finally, when transaction utility is given, purchase intentions of essential goods increase under low retailtainment, and the purchase intentions of non-essential goods increase under high retailtainment. Conclusions - When customers buy essential goods, discounts decrease purchase intentions. During the season for bargain sales, purchase intentions increase when retailtainment of essential goods is low, and retailtainment of non-essential goods is high.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.60-62
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• 1996