• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.1-3
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• 2005

This paper is to evaluate practical advantage in using maximizing efficiency control strategy in induction motor drives for electric vehicles. A maximizing efficiency control strategy consist of a flux estimation with direct field oriented controller is proposed and compared with the general constant flux control strategy. The comparison is carried out by simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.513-514
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• 2007

최근 들어, 디지털 보호 계전기의 계측 및 계전 기능 외에 운용 프로그램 및 사고파형 분석 기능 또한 중요시 하고 있는 실정이다. 이를 위해 저장된 사고파형을 분석하기 위한 프로그램 개발이 요구되어 지고 있으며 본 논문에서는 다양한 기능을 가지는 사고파형 분석 프로그램을 소개한다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.51-52
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• 2022

The electro-mechanical impedance(EMI) behavior of piezoelectric sensor embedded in cement mortar was investigated to assess the setting times. EMI signal was continuously measured for 12 hours by the PZT sensor embedded in cement mortar with different ratio of sand. As a result, the setting times by the penetration resistance test were accelerated as the sand ratio increased. However, the setting times by EMI sensing technique were delayed as the sand ratio increased.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.7-14
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• 2015

The machine tools builders are trying to improve the efficiency and performance of the machine tools. The electro-mechanical driven broaching machine has many advantages such as lower noisy operating, higher energy efficiency, and smaller space of installation. This paper presents the structural and mechanical development of an electro-mechanical driven broaching machine that is replaced for traditional hydraulic one. The servo motor, ball screw and roller linear guide are used instead of hydraulic cylinder and translation frictional sliding guides. The simulation method based on FEM was applied to analyze the stress, deformation of the machine for static analysis. The dynamic analysis was carried out for verifying and assessing the mechanical behavior of the developed broaching machine. This work helps broaching machine developer make a better product at the early design stage with lower cost and development time.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1473_1474
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• 2009

To develop electrically reliable high voltage apparatuses, the experimental study on the electrical breakdown field strength is needed, as well as theoretical approach. In this paper, lightning impulse breakdown characteristics considering utilization factors are investigated for the establishment of insulation design criteria of an high voltage apparatus. The utilization factors are represented as the ratio of mean electric field to maximum electric field. Dielectric experiments are performed by using five kinds of sphere-plane electrode systems made of stainless steel. As a result, it is found that dielectric characteristics are affected by not only gap length but also utilization factor of electrode systems. The results are expected to be applicable to the design of high voltage apparatuses.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.77-89
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• 2020

This paper proposes a simple and intuitive model-free torque-tracking control for rotary electro-hydraulic actuators. The undesirable natural-velocity-feedback effect is discussed by introducing mechanical impedance into the electro-hydraulic actuation system. The proposed model-free torque control comprises inner- and outer-loop control to achieve two control objectives. Inner-loop control reduces the mechanical impedance passively and optimally. To improve the tracking accuracy, a certain form of proportional-integral-derivative control is applied to the outer loop. The robustness of the proposed closed-loop system against external disturbances is demonstrated by transforming the two-loop control structure into a disturbance observer form. The proposed method is validated on a single joint electro-hydraulic actuator.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.101-104
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• 2004

대체에너지 시스템에서 필수적인 계통연계형 인버터는 LC필터를 거친 정현전압 출력에 계통과 연계용 인덕터를 연결하여 사용하여 왔으나, 최근 들어 인버터와 계통을 LC필터 없이 인덕터로만 계통과 연결하여 직접 전류를 제어하는 형태가 적용되고 있다. 또한 출력에 절연 변압기를 사용하던 기존방식과 달리 변압기가 없는 비절연형 인버터는 전류제어를 통해 계통과 직접연결하고, 부피감소와 원가절감을 이룰 수 있다. 본 논문에서는 저주파 절연변압기가 없는 3kW급의 태양광 발전시스템 시제품을 소개하고 단상계통과 연계한 전류제어 알고리즘의 실험결과를 통해 순시전류제어의 타당성을 확인한다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.629-631
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• 2001

중저압 분야에서 가장 많이 사용되는 차단기는 진공차단기이다. 진공차단기는 $SF_6$에 비하여 간단하며, 아크소호 능력 또한 뛰어나다. 이런 진공차단기에서 차단성능에 가장 중요한 부분이 진공차단부이다. 본 논문에서는 constricted arc와 diffuse arc에 관하여 서술하였으며, contrate type 진공차단부의 다양한 형상변경에 따른 직교자계와 축자계에 대한 3차원 전자계 해석을 수행하였다. 3차원 전자계해석으로 얻어진 결과는 새로운 진공차단부 개발에 커다란 도움이 될 것으로 사료된다.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2855-2857
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• 2005

디지털 선박(Digital Ship)이란 항해의 안전과 효율적 운행을 위해 항해, 조정, 상태감시 등 선박운행에 대한 전반적인 내용들을 컴퓨터를 통해서 구현하고 위성통신을 통해서 육상에서도 제어할 수 있는 완전 자동화 및 네트워크화 된 시스템을 의미하며 궁극적으로 무인화된 선박을 지향한다. 또한 통한항해시스템이란 선박의 경제적이고 안전한 운항을 위해 전자해도와 레이더를 이용하여 선박의 항로를 계획하고 감시하며 최적 항로 분석, 충돌/좌초방지 및 자동항법시스템과 연계한 자동항해 기능을 수행한다. 본 논문은 디지털 선박을 위하여 항해정보시스템과 항해 장비 통합장치 및 통신서버를 기반으로 한 전자해도와 레이더, 자동항법장치(autopilot) 및 각종 항해센서의 다기능 표시장치의 기능과 인터페이스 방안을 제시하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.489-491
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• 2005

This paper presents the application study of substation automation protocol, IEC 61850 to digital relay (HiMAP). Especially, it implements the data modeling, ACSI definition, GOOSE, MSVCB and data service required in the existing digital relay. To verify the system performance, we develop the process emulator and HiMAP emulator, and describe the results.