• 한국ITS학회 논문지
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• 제8권6호
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• pp.64-72
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• 2009

본 논문에서는 마이크로스트립 패치 안테나와 2차 및 3차 고조파가 억압된 이중모드 대역통과 여파기를 이용하여 고효율의 2.45 GHz 렉테나를 설계 및 제작하였다. 입사전력밀도가 0.3 mW/cm2 일 때 1.66 mW 의 전력을 수신하였고, 41.6%의 RF-to-DC 변환효율의 실험 결과를 얻었다. 이는 입사 전력이 작기 때문에 다른 논문의 결과와 비교하여 고효율이라고 볼 수 있다. 또한 무선전력 전송을 통하여 다양한 응용기술 개발에 활용이 가능할 것으로 예측되며, USN(Ubiquitous Sensor Network)용 저전력 소자의 대기전원 공급 및 MEMS용 Sensor 등의 구동전압공급을 위한 무선 전력전송이 가능하게 될 것으로 기대된다.

• 조명전기설비학회논문지
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• 제21권5호
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• pp.99-105
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• 2007

본 논문에서는 초 중 고등학교 전기시설물을 대상으로 전기안전에 대한 현장조사를 하였다. 현장조사는 수전설비, 교실, 과학실 및 음악실 등을 대상으로 연구원, 경력 15년 이상의 전기기술자 및 기타 관련 전문가에 의해 전국적으로 수행하였다. 41개 학교를 대상으로 현장조사를 실시한 결과, 수전설비의 접지방식은 공통접지방식이 지배적이었다. 위험요소로는 선풍기 조절기함의 부재, 실험대 전원의 인체보호용 누전차단기의 미설치, 비접지 콘센트의 사용 등으로 나타났다.

• 한국정밀공학회지
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• 제20권1호
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• pp.99-106
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• 2003

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system. In order to realize these tasks autonomously, the there dimensional position of target object such as electric line and the stand of insulator must be recognized accurately and rapidly. The insertion task of an electric line into a sleeve is selected as the typical task of the maintenance of active electric power distribution lines in this paper. A modified hough transform is applied to the recognition of the center of electric line and optimal target position calculation method is newly derived in order to recognize the center 3 dimensional position of the electric line. By the proposed method, it is proved that the center position of the electric line can be recognized without respect to the noise of image and the shape of electric lines and the insertion task of an electric tine is realized.

• Journal of Power Electronics
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• 제9권5호
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• pp.679-690
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• 2009

The paper presents a new photovoltaic inverter for stand-alone induction motor application. The proposed system is composed of two stages. First stage is for the photovoltaic dc power feeding and second stage is dedicated to the motor-inverter subsystem and control technique. A direct torque control (DTC) with a novel switching strategy for motor torque ripple minimization is introduced. The novel DTC strategy is based on selecting a suitable voltage vector group for motor torque ripple minimization. A three-level voltage source inverter (VSI) is used instead of a two level inverter because the first has more available vectors and lower ripples in the output current and flux than the second, thus it has lower torque ripples. The photovoltaic array and battery bank are sized and the configuration is indicated based on sun-hour methodology. Simulation results show a comparison between three systems; two level VSI with conventional DTC strategy, three level VSI with conventional DTC, and the proposed system that has a novel DTC switching strategy applied to three level VSI. The results show that the proposed system has lower ripples in the current, flux and torque of the motor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.429-430
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• 2011

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology with coupled inductors. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charging mode, constant-current mode, and constant-voltage mode. The pre-charging mode employs the staircase shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is able to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 67A. The optimal discharging algorithm for Vehicle to the Grid (V2G) operation has been adopted to maintain the discharging current of 1C. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.679-680
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• 2008

Most of the small wind turbines are set as the stand alone type in the area where the access to the grid is difficult and compulsorily uses the battery. Depending on the volume of the battery, securing of the space necessary, and has the shortcoming of replacing the battery periodically due to it's limited working life span. Recently, setting up in the vicinity of the city area is increasing and the trend of using the Grid inverter instead of battery is also increasing. This thesis is aiming mainly analyzing the characteristics of the output power of the Prototype Permanent Magnet Generator(PMG) and the Grid-Inverter and to verify through the theoretical study and tests. Tested the characteristics of the output power of the PMG through the stage 1-2 and at the stage 3 connected the output of the PMG to the Inverter and tested the characteristics of the Inverter. And at the stage 4, the maximum output power is confirmed by the continuous running test of the PMG.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.323-324
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• 2013

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charge mode, constant-current mode, and constant-voltage mode. The pre-charge mode employs the stair-case shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is specified to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 78A. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.

• 한국정보통신학회논문지
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• 제10권11호
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• pp.2014-2019
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• 2006

PDP구동회로는 160V 이상의 고전압을 유지하기 위한 스위칭 소자와 커패시터를 필요로 한다. 이러한 고전압용 소자의 사용은 PDP 구동회로의 가격을 상승시키고 전력 소모를 증가시키는 원인이 된다. 기존의 PDP 구동회로는 3개의 공급 전압원과 16개의 스위칭 소자로 구성 되어 있다. 그러나 본 논문에서는 2개의 공급 전압원과 12개의 스위칭 노자를 사용하고, 공급 전압도 기존의 공급 전압보다 낮은 공급 전압을 사용하는 구동회로를 제안한다. 컴퓨터시뮬레이션을 통하여 입력 주파수가 70kHz에서 100kHz일 때 45V 이상의 공급전압을 사용한다면 PDP 셀 구동을 위한 충분한 크기의 신호를 얻을 수 있음을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.201-202
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• 2012

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charging mode, constant-current mode, and constant-voltage mode. Each mode is operated according to battery states: voltage, current and State of Charging (SOC). The proposed system is able to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 67A. The optimal discharging algorithm for Vehicle to the Grid (V2G) operation has been adopted to maintain the discharging current of 1C. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system. Experiment waveforms confirm the proposed functionality of the charging system.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.162-163
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• 2022

Maritime transportation is going to transfer to alternative fuels as a result of the worldwide demands toward decarbonization and tougher maritime emissions regulations. Methanol is considered as a potential marine fuel, which has the ability to reduce SOx and CO₂ emissions, reduce climate change effects, and achieve the objective of green shipping. This work proposes and combines the innovative combination system of direct methanol solid oxide fuel cells (SOFC), proton exchange membrane fuel cells (PEMFC), gas turbines (GT), and organic Rankine cycles (ORC) for maritime vessels. The system's primary power source is the SOFC, while the GT and PEMFC use the waste heat from the SOFC to generate useful power and improve the system's ability to use waste heat. Each component's thermodynamics model and the combined system's model are established and examined. The multigeneration system's energy and exergy efficiency are 76.2% and 30.3%, respectively. When compared to a SOFC stand-alone system, the energy efficiency of the GT and PEMFC system is increased by 19.2%. The use of PEMFC linked SOFC has significant efficiency when a ship is being started or maneuvered and a quick response from the power and propulsion plant is required.