• 한국산업융합학회 논문집
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• 제14권1호
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• pp.29-36
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• 2011

This study analyzed the convenience and productivity before and after adopting self-propelled power transportation devices to the harvest and transportation of fruit and vegetable products in the Gyeongbuk region, by applying the REBA and RULA techniques. In the REBA analysis, the work risk was low with 4~6 points before adoption which became 2~3 points after adoption. As for the RULA analysis, work loading appeared to have decreased with 6~7 points before adoption which became 3~4 points after adoption. The annual work time reduction was about 48~179 hours while labor costs were reduced to 364~1,345 thousand won annually. This indicated a labor cost reduction effect of about 10~15%. Therefore, the adopted self-propelled power transportation devices appeared to prevent musculo skeletal diseases of the human body and also improve productivity even after using it for long hours according to the REBA, RULA measures level.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.33-34
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• 2014

In this paper, the inverter switch losses of BLDC motor for three types of PWM method and power devices was analyzed. When BLDC motor is driven at low currents, inverter switch losses for MOSFET is low because MOSFET operates like resistance. But, inverter switch losses for IGBT is higher than MOSFET due to its large turn-off losses. For low power inverter with MOSFET, the power losses of unified PWM is lower than that of unipolar and bipolar PWM.

• 전기학회논문지P
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• 제64권4호
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• pp.286-290
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• 2015

Power system is composed of a number of power devices and equipment. This factor affects the power quality is also displayed very complicated and varied. The accurate measurement and analysis of the causes of power quality problems is difficult. In preparing for these issues, there are many difficulties. In this study, Power quality of A public establishment of Chungbuk province were measured and analyzed. Measurement results of the fifth harmonic current was very large. Accordingly, the harmonic reduction will be needed. This research will be utilized as fundamental data to improve power quality for power utility and customer.

• 한국컴퓨터정보학회논문지
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• 제29권1호
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• pp.195-209
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• 2024

1990년대 개발되어 현재의 모습을 갖춘 교통신호제어기는 최근 도로 이용자의 교통안전 향상 및 자율협력주행 등을 목적으로 설치되는 다양한 장치들에 대한 전원공급 문제와 다양한 통신방식, 계층화된 블랙박스 구조 등으로 인해 유연성과 확장성에 한계를 가지고 있다. 이에 본 논문에서는 이더넷전원장치(PoE : Power over Ethernet) 기술을 통해 직류(DC) 전원 사용과 전원공급 문제를 해결하고, 메시지 브로커(Message Broker) 기술을 통해 중앙화된 데이터 기반 제어를 함으로써 빠르게 변화하는 미래 교통환경에 대응이 가능한 교통안전시설 통합관제시스템을 설계하였다. 또한 시계열 데이터를 기반으로 동작하는 교통안전시설 장치를 위한 데이터 기반 실시간 제어 방안을 구현하고 검증하였다.

• 전력전자학회논문지
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• 제21권2호
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• pp.117-125
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• 2016

In this paper, the inverter switch losses of BLDC motor for three types of PWM methods and power devices were analyzed. When the BLDC motor is driven at low currents, the inverter switch losses for MOSFET are low because MOSFET operates like resistance. However, the inverter switch losses for IGBT are higher than MOSFET due to its large turn-off losses. Moreover, synchronous rectification switching method is adaptable because MOSFET has 2-channel. So, MOSFET can be driven with more low impedance and losses. For low power inverter with MOSFET, the power losses of unified PWM are lower than that of unipolar and bipolar PWM. Proposed method and losses analysis results are verified by examination and simulation using Matlab/Simulink.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2023년도 제68차 하계학술대회논문집 31권2호
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• pp.673-674
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• 2023

도로교통의 안전 확보와 사고 예방을 목적으로 운전자나 보행자에게 필요한 정보를 제공하기 위해 경찰청에서 규격 또는 지침으로 제정하여 노변에 설치되는 교통안전시설 장치는 교통신호정보를 받기 위한 통신선과 함께 장치 구동을 위한 전원선을 개별로 시공해야 하기에 시공 비용의 절감과 함께 다종·다형의 장치에 대하여 통합적인 관제, 확장성, 유연성에 대응할 필요성이 제기되고 있다. 이에 본 논문에서는 이더넷 통신을 기반으로 전원 공급이 하나의 케이블로 가능한 이더넷 전원장치(PoE) 기술과 IoT 프로토콜인 MQTT를 이용하여 다종·다형의 교통안전시설 장치를 통합관제하고, 확장성과 유연성을 가지는 교통안전시설 장치 통합 시스템을 제안한다.

• 전기학회논문지
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• 제63권1호
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• pp.184-190
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• 2014

Fuel cell power system, unlike conventional energy sources, converts chemical energy into electrical energy through electrochemical reaction of hydrogen and oxygen. In recent years, railway field as well as mobile fuel cell power system is being studying actively with development of hydrogen storage technologies. This paper presents the feasibility study on small-scale prototype electric railway vehicle application using fuel cell generation system. it is confirmed that proposed fuelcell-battery hybrid system shows good response characteristic about speed and torque based on design of parameter on system. Also as results of response for proposed system modeling, it show that powering mode and braking mode of system is controlled by switching devices of converters.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.95-98
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• 1998

Applying the magnetically levitated transportation system, which is noncontact bearing system, to solve the problems such as transformation of original form or flaw of iron plate caused by transportation of thin iron plate which required high quality as body of motor vehicle, materials of electronic devices etc.. Magnetic saturation phenomena caused by thickness of iron plate and gap size between magnets. In case of iron plate, the vibration mode will be considered since vibration occurs during transportation. In order to solve the problems caused by vibration, choose the levitation system method using numbers of magnet, magnetic saturation for thickness and length of iron plate with parameters in location and gap of magnet. In this paper, we will suggest the whole design technique of magnetically levitated transportation system, namely method of magnetic attraction and transportation system

• 전력전자학회논문지
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• 제26권3호
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• pp.205-213
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• 2021

Due to the advantage of reducing the voltage applied to the switch semiconductor, the input series and output parallel combination is widely used in systems with high input voltage and large output current. On the other hand, the LLC converter is widely used as a high-efficiency power converter, and when connected by ISOP combination, there is a possibility that input voltage imbalance may occur due to a mismatch of passive devices. To avoid damaging the switching device, this study analyzed the DC-link voltage imbalance of a high-capacity supply using an ISOP LLC converter. In addition, the case where DC-link unbalance control was applied and the case not applied was analyzed respectively. Based on this analysis, an initial start-up algorithm was proposed to prevent input power semiconductor device damage due to DC-link over-voltage. The effectiveness of the proposed algorithm has been verified through simulations and experiments.

• 문화기술의 융합
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• 제9권2호
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• pp.143-150
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• 2023

우리나라의 1인당 국민소득이 증가하면서 장애인의 삶의 질 향상을 위한 다양한 여가 활동에 참여가 장려되고있다. 그러나 여가활동 참여를 위해서는 여가가 행해지는 장소까지의 이동이 선행되어야 하므로, 장애인의 여가활동을 위한 이동수단에 대한 관심이 커지고 있다. 수동 및 전동 휠체어는 여가활동을 위한 이동수단으로서 각각의 단점을 가지고 있어서 수동 휠체어에 전동 휠체어의 기능을 접합하는 휠체어 동력보조 장치에 대한 관심이 높아지고있다. 본 연구에서는 휠체어 동력보조 장치 제품들의 FDA 승인 과정을 조사하고, 세계 각국에서 생산하는 측면부착형, 전방부착형, 하방부착형, 후방부착형 휠체어 동력보조 장치들의 특성을 파악하였다. 이러한 정보들은 국내 장애인 및 보조인들이 환자의 상태에 따라 최적의 제품을 선택하는데 큰 도움이 될 것이다. 장애인들이 자신에게 적합한 동력 보조 장치를 선택할 수 있도록 많은 사용적합성 시험과 임상사례 연구가 필요하다.