• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.164-168
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• 2005

In this paper a statcom is developed to improve the power quality in a dc traction system. The proposed statcom can be used as both inverter and active filter. As an active filter, it can compensate harmonic distortion and reactive power and as an inverter, it can recycle regenerative energy caused by decelerating trains. The simulation results are carried out by using PSCAD/EMTDC software.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.63
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• pp.89-99
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• 2001

This paper proposes assessment of quality management activities based on cost of quality. Cost of quality is considered prevention cost, appraisal cost, internal failure cost, external failure cost in this paper. This paper shows quality cost magement system in thermal power site devision according to activity analysis. Cost of quality in power industries provides a valuable method of both proving the need for improvement and giving a starting point for projects.

• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.10-21
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• 2012

As one of the key IT applications, the project management information system (PMIS) played a significant role in construction management processes in Korea. On increasing use of PMIS, regular quality assessment to identify user's requirements of PMIS is necessary. However, there have been rare research efforts for quality assessment for the construction PMIS. This paper aims to propose a priority index of quality improvement for construction PMIS using the importance and satisfaction measures and to verify the discrimination power of the priority index by comparing it with other quality improvement priority index. In addition, this paper discusses some possible ways of PMIS quality improvement. The analysis of quality improvement priority was based on a questionnaire responded by 253 PMIS users (construction managers and constructors). The methods of PMIS improvement were based on the interviews with eight experts. These findings would be the foundation of further researches on PMIS quality improvement. However, more efforts are required to enhance the priority index, in terms of reflecting weighted values of quality assessment factors.

• Journal of Power Electronics
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• v.8 no.2
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• pp.109-120
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• 2008

In this paper, a novel delta/double-fork transformer based 18-pulse full-wave AC-DC converter is designed, modeled, simulated and developed to feed isolated DC varying loads. The proposed AC-DC converter is used for low voltage and large current DC loads in applications such as electrowinning, where isolation is required mainly for stepping down the supply voltage. The proposed converter improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.513-516
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• 2004

In this paper, a PWM Cuk AC-AC converter for power quality improvement of custom power is presented. The PWM Cuk AC-AC converter that is used in VVCF applications such as AC line conditioner, phase shifter is modelled by using complex circuit DQ transformation whereby the static characteristics equations such as voltage gain and power factor is analytically obtained. Finally, the PSIM simulation show the validity of the modelling and analysis.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.153-160
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• 2006

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for dc voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

• Journal of Power Electronics
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• v.15 no.4
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• pp.1054-1065
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• 2015

Multi-functional voltage source inverters (VSIs) have attracted increasing attention in recent years for their advantageous auxiliary services for power quality enhancement in autonomous microgrids. These types of VSIs can not only achieve a proper control scheme in autonomous mode but also cope with the prescribed power quality and stability requirements. These functionalities are integrated within the same device, thereby significantly improving the cost-effectiveness of microgrids while decreasing the investment and bulk compared with those of multiple devices with independent functionalities. Control strategies for power quality enhancement in autonomous microgrids using multi-functional VSIs are comprehensively reviewed in this paper. In addition, such VSIs are discussed in detail, and comparisons of which are also provided. Lastly, a number of future research directions for multi-functional VSIs are recommended.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.30
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• pp.193-198
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• 1994

The quality culture, part of the corporate culture, is an operating philosophy of quality management of the corporation. Ultimately it assures and maintains the customer satisfaction and promotes the customer-oriented corporate management In this paper, to help meet the consumers' diversified demand and prepare the turning point of development of competitive power according to the recent rapid industrial change, proposes the efficient methods of qualify improvement activity based on creation and fixation of quality culture.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.2
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• pp.53-58
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• 2006

This paper proposes a small low-cost power quality compensator to be installed at the electricity supply inlet of residential customer. The compensator is composed of a single-phase active power filter with a simple controller using analog electronics, which can correct the power factor and damp out the harmonics. The operation and performance of proposed compensator was verified through simulations with PSCAD/EMTDC and experimental works with hardware prototype. The proposed compensator can offer reduction of power loss and improvement of power quality to the residential customer.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.77-79
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• 2007

The phase angle of the utility voltage is used in current control of grid-tied fuel cell power converter. Therefore if the detection of phase angle is a problem, Current control is affected by the distorted phase angle. This paper presents a problem of synchronous reference frame PLL algorithm for single-phase systems and proposes compensated synchronous reference frame PLL algorithm. The proposed method helps power quality improvement of grid-tied fuel cell power converter under distorted utility conditions. Simulation and experimental results are presented to demonstrate the validity of the proposed method.