• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.12
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• pp.28-32
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• 2015

In this work, we reported fabrication of sealing the glass substrate using laser treatment at low temperature for electrochemical luminescence (ECL) cell. The laser treatment at temperature is using laser diode. The glass substrate sealing by laser treatment tested at 3-10W, 2-5 mm/s for build and tested. The sealing laser treatment method will allow associate coordination between the two glass substrate was enclosed. The effect of laser treatment to sealing the glass substrate was found to have cracks and air gap at best thickness of about 550-600 im for condition 3 W, 3 mm/s. The surface of sealing was roughness which was not influent to electrodes It can reduce the cracks, crevices and air gaps as well, improves the performance viscosity in butter bus bar electrodes. Therefore, it is more effective viscosity between two FTO glasses substrate.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.313-319
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• 2000

In order to design the current carrying conductor for GIS, it is important to predict temperature-rise when rated current flows in the bus bar. However, it is not easy to apply the correct heat transfer coefficient on the boundary between different material for the thermal analysis. In this paper, the heat transfer coefficient which depends on parameters such like material constant, model geometry as well as ambient temperature, was calculated by analytic method. The calculated coefficient is used for the temperature rise prediction by F.E.M. The results show good agreement with experimental data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.942-945
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• 2005

This paper tried to analyze the collection and management method of shop-floor information for development of digital framework in u-manufacturing. In detail, the shop-floor information collection method through the direct communication with manufacturing devices using network Including RS-232C/422, field bus and ethernet is analyzed and proposed. In case the direct communication is impossible, the information collection method through additional sensors or data acquisition units is analyzed and proposed. Moreover, the collection method through bar code reader or touch screen of operators is analyzed and proposed to act up to machine to man/mobile/machine.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.25-30
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• 2017

Arago's disk system consists of a speed controller of the DC motor (inner loop controller) and a position controller of the magnetic bar angle (main controller), which are implemented by the design of the PI and PID controller, respectively. First, we analyzed the nonlinear characteristics of the Arago disk system and found the operating point range of three locations as a result. In this paper, a gain scheduler method was applied to guarantee a constant control performance in the range of $0{\sim}130^{\circ}C$, and a structure to change the controller according to the control reference value based on the previously obtained operating points was experimentally implemented. The Distributed Control Systems (DCS) configuration using the Controller Area Network (CAN) was used to verify the proposed method by improving the operational efficiency of the entire experimental system. So, simplicity of the circuit and easy diagnosis were achieved through a single CAN bus communication.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.239-241
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• 2019

기존 이동 트레이 카트의 모터를 구동하기 위해 사용되는 외부 전원 장치는 Bus Bar를 사용함으로써 내구성이 떨어지고 잦은 유지보수가 필요하고 모터 구동을 위해 70v 이상의 전압을 필요로 한다. 또한 기존 카트 시스템은 카트 동시배출, 모터 드라이브 대기전력, 발전량 부족 등 다양한 문제를 갖고 있기 때문에 이를 해결하기 위한 방법으로 본 논문에서는 입력을 배터리로 적용시켜 3배 이상 승압이 가능한 배압회로, 카트 동시 배출을 위한 Super Cap String, 발전량 부족을 해결하기 위한 발전기 병렬 연결을 통해 발전량을 증가 시킬 수 있는 시스템을 제안하고 이를 이론적, 실험적 분석을 통해 그 타당성을 검증한다.

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.467-476
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• 2008

To keep the superconducting (SC) magnet coils of KSTAR at proper operating conditions, not only the coils but also other cold components, such as thermal shields (TS), magnet structures, SC bus-lines (BL), and current leads (CL) must be maintained at their respective cryogenic temperatures. A helium refrigeration system (RRS) with an exergetic equivalent cooling power of 9 kW at 4.5 K without liquid nitrogen ($LN_2$) pre-cooling has been manufactured and installed. The main components of the KST AR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The process helium is compressed from 1 bar to 22 bar passing through the WCS and is supplied to cryogenic devices. The main components of cryogenic devices are consist of cold box (C/B) and distribution box (D/B). The C/B cool-down and make the various cryogenic helium for the KSTAR Tokamak and the various cryogenic helium is distributed by the D/B as per the KSTAR requirement. In this proceeding, we will present the commissioning results of the KSTAR HRS. Circuits which can simulate the thermal loads and pressure drops corresponding to the cooling channels of each cold component of KSTAR have been integrated into the helium distribution system of the HRS. Using those circuits, the performance and the capability of the HRS, to fulfill the mission of establishing the appropriate operating condition for the KSTAR SC magnet coils, have been successfully demonstrated.

• Current Photovoltaic Research
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• v.4 no.2
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• pp.59-63
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• 2016

A key point of a soldering process for photovoltaic (PV) modules is to increase an adhesive strength leading a low resistivity between ribbon and cell. In this study, we intended to optimize a heating condition for the soldering process and characterize the soldered joint via physical and chemical analysis methods. For the purpose, the heating conditions were adjusted by IR lamp power, heating time and hot plate temperature for preheating a cell. Since then the peel test for the ribbon and cell was conducted, consequently the peel strength data shows that there is some optimum soldering condition. In here, we observed that the peel strength was modified by increasing the heating condition. Such a soldering property is affected by a various factors of which the soldered joint, flux and bus bar of the cell are changed on the heating condition. Therefore, we tried to reveal causes determining the soldering property through analyzing the soldered interface.

• Journal of Power Electronics
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• v.18 no.2
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• pp.375-382
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• 2018

A novel active controlled primary current cutting-off zero-voltage and zero-current switching (ZVZCS) PWM three-level dc-dc converter (TLC) is proposed in this paper. The proposed converter has some attractive advantages. The OFF voltage on the primary switches is only Vin/2 due to the series connected structure. The leading-leg switches can obtain zero-voltage switching (ZVS), and the lagging-leg switches can achieve zero-current switching (ZCS) in a wide load range. Two MOSFETs, referred to as cutting-off MOSFETs, with an ultra-low on-state resistance are used as active controlled primary current cutting-off components, and the added conduction loss can be neglected. The added MOSFETs are switched ON and OFF with ZCS that is irrelevant to the load current. Thus, the auxiliary switching loss can be significantly minimized. In addition, these MOSFETs are not series connected in the circuit loop of the dc input bus bar and the primary switches, which results in a low parasitic inductance. The operation principle and some relevant analyses are provided, and a 6-kW laboratory prototype is built to verify the proposed converter.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.155-159
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• 2016

In this work, we have developed a test system to examine whether the charge indicator of the plug-in hybrid electric vehicle (PHEV) works properly or not. In PHEV, the driver should charge the necessary electricity by plugging in manually and be able to know the charging status through the charge indicator conveniently located for the charging individual. Our system used the CAN bus to transmit the same commands from ECU to the indicator to test the proper operation of the indicator lights. It measured the electric current values during operation and analyzed to determine the quality of the indicators. The inspection items included the proper packaging, the electrical shorts, the LED lighting during charging, the LED lighting for charging failure, and the LED lighting when errors occur. We developed the system for the operators in the factory allowing them to approve the test results at the site. We developed the hardware, the control software, and the software to store the test results and the history of the products in the database. Serial numbers were given to the good quality products and the bar code labels were printed to trace the products afterwards. Through this work, we developed a system to inspect the electric parts in real time upon fabrication. We are planning to further improve our system to inspect the brightness of the indicator by adding the vision inspection in future.

• Progress in Superconductivity
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• v.1 no.1
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• pp.68-72
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• 1999

Since the discovery of high Tc superconductors, great efforts have been focused to develop high performance HTS magnets for the ultimate applications to power system devices. Magnet designers, however, have had difficulties in the estimation of the maximum operating current of the designed magnet from the tested short sample data, due to the degradation of the critical current density in the magnet. Similar story applies to the HTS electrical bus bar. It has been found that the critical current of Bi-2223 stacked tapes is much less than the total summation of critical currents of each tape, which is mainly attributed to the self magnetic fields. Furthermore, since the critical current degradation of Bi-2223 tape is greater in the normal magnetic field (to the tape surface) than in the parallel one, detailed magnetic field configurations are required to reduce the self field effects. In this paper, we calculate the self field effects of a stacked conductor, defining self field factors of normal and parallel magnetic fields to the tape surface. Finally, the critical current degradations in the HTS magnet are explained by the introduced self field factors of the stacked conductor.