• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.36-46
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• 2008

This paper is to study on the Construction of Test circuit and Unification of Experiment Method for high voltage gas-insulated load switch using high power testing system The high power testing system is a equipment to verify electrical and mechanical performance on electrical product. The system consist of short-circuit generator, back-up breaker, making switch, impedance, high voltage transformer, low voltage transformer, measuring and protection system, etc. Using this system, we can test related to high power, for example, short-time current test, active load Current test, magnetizing Current test, capacitive current test, closed loop current test, etc. Standards of high voltage gas-insulated load switch that is in use domestic distribution line are ES 5925-0002, IEC 60265-1, IEC 62271-1 and IEEE C 37.74, etc. In this paper, we standardized on the test procedure, organization of test circuit and analysis of measured data prescribed many difference standards, and applied this test method to 600[MVA] high power testing system. So that we can test the load switch satisfied standards.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.27-36
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• 2021

A capacitive water sensor was developed to measure the capacitance over a wide part of a substrate using an insulated electrode plate (30 cm × 10 cm) with copper and Teflon attached on either side of the substrate. This study aimed to convert the capacitance output obtained from the condenser-type capacitance sensor into the substrate water content. The quantification experiment was performed by measuring the changes in substrate water weight and capacitance while providing a nutrient solution and by subsequently comparing these values. The substrate water weight and capacitance were measured every 20 to 30 seconds using the sensor and load cell with a software developed specifically for this study. Using a curve-fitting program, the substrate water content was estimated from the output of the capacitance using the water weight and capacitance of the substrate as variables. When the amount of water supplied was increased, the capacitance tended to increase. Coefficient of variation (CV) in capacitance according to the water weight in substrate was greater with the 1.0 kg of water weight, compared with other weights. Thus, the fitting was performed with higher than 1.0 kg, from 1.7 to 6.0 kg of water weight. The correlation coefficient between the capacitance and water weight in substrate was 0.9696. The calibration equation estimated water content from the capacitance, and it was compared with the substrate water weight measured by the load cell.

• Journal of Sensor Science and Technology
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• v.19 no.1
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• pp.25-30
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• 2010

This paper presents a low noise CMOS regulator for a low power capacitive sensor interface in a $0.5{\mu}m$ CMOS standard technology. Proposed LDO regulator circuit consist of a voltage reference block, an error amplifier and a new buffer between error amplifier and pass transistor for a good output stability. Conventional source follower buffer structure is simple, but has a narrow output swing and a low S/N ratio. In this paper, we use a 2-stage wide band OTA instead of source follower structure for a buffer. From SPICE simulation results, we got 0.8 % line regulation and 0.18 % load regulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1426-1431
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• 2015

Piezoelectric pump can be considered as R-C load and it needs something special driver because the output voltage does not become 0 even though the applied voltage is 0 with common converter. This operating system consists of fly-back converter to increase the input voltage and energy recovery inverter to apply square voltage to the piezoelectric pump. The energy recovery inverter can charge and discharge the energy of capacitive load. In this paper, to enhance performance of the driver, a few elements or circuits are added and modified. To drive the inverter safely, current limit resister is added and adjusted the value to valance the charging and discharging current. In addition, a current limit inductor is added to the input side to limit the input current and enhance the efficiency. Inductor only may make oscillation and another resister is added parallel to the inductor to solve this problem. The converter and inveter are assembled to one board for compactness. The appropriateness is proved with simulation and experiments.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.3
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• pp.117-121
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• 2005

Power system restoration following a massive blackout starts with re-energizing primary transmission lines at first. Some factors such as Ferranti effect, and line charging reactive power should be considered in this stage. Severe overvoltage may be induced by the Ferranti effect at the lines since it would be usually no load condition. And lack of capacitive reactive power will cause the self-excitation. This paper presents a new precise algorithm to analyze the primary restorative transmission system focused on the two major static overvoltage problems during the early restoration process.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.564-567
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• 2004

New address electrode having separated dual electrode is suggested to reduce addressing time in ac PDP. Addressing characteristics of suggested electrode has been investigated in the test panel with high Xe partial pressure. It has been found that both the formative and jitter width of the suggested electrode is improved by 10 -20 % over the wide range of address voltage level compared with the conventional one. The dynamic margin of the panel also greatly improved. The key feature behind this type of structure is that it can extend the controllability of the wall charge distribution during the reset and address discharge without significant increase in capacitive load of address electrode.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.777-781
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• 2004

This paper presents a force/displacement sensing system to measure penetration depths and machining forces during pattering operation. This sensing system consists of a leaf spring mechanism and a capacitive sensor, which is mounted on a PZT driven in-feed motion stage with 1nm resolution. The sample is moved by a xy scanning motion stage with 5nm resolution. The constructed system was applied to nano indentation experiments, and the load-displacement curves of silicon(111) and aluminum were obtained. Then, the indentation samples were measured by AFM. Experimental results demonstrated that the developed system has the ability of preforming force/depth sensing indentations

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.443-445
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• 2008

용량성 부하를 사용하는 응용사례가 늘어남에 따라 에너지 회수 회로의 중요성 또한 더욱 부각되고 있다. 특히, 고전압 구동의 경우 에너지 회수를 하지 않을 경우 손실이 크게 발생하며 충방전시 돌입 전류로 인한 노이즈 문제 또한 발생하게 된다. 본 논문에서는 단권변압기를 사용한 새로운 형태의 에너지 회수 회로를 제안한다. 제안한 회로는 모든 스위치가 동일한 전압, 전류 스트레스를 받으며 항상 스위치를 통해 흐르는 전류가 대칭적으로 분배되기 때문에 도통 손실을 줄일 수 있으며 단권변압기를 통하여 용량성 부하가 연결되기 때문에 영전압 실패시 발생 할 수 있는 돌입 전류로 인한 전자파 발생 및 도통, 스위칭 손실을 막을 수 있다는 장점을 갖는다. 이에 대한 이론적 해석과 시뮬레이션과 용량성 부하를 이용한 실험을 통해 타당성을 검증하였다.

• ETRI Journal
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• v.29 no.6
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• pp.785-793
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• 2007

In this paper, we present an integrated rail-to-rail fully differential operational transconductance amplifier (OTA) working at low-supply voltages (1.5 V) with reduced power consumption and showing high DC gain. An embedded adaptive biasing circuit makes it possible to obtain low stand-by power dissipation (lower than 0.17 mW in the rail-to-rail version), while the high DC gain (over 78 dB) is ensured by positive feedback. The circuit, fabricated in a standard CMOS integrated technology (AMS 0.35 ${\mu}m$), presents a 37 V/${\mu}s$ slew-rate for a capacitive load of 15 pF. Experimental results and high values of two quality factors, or figures of merit, show the validity of the proposed OTA, when compared with other OTA configurations.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1000-1001
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• 2015

본 논문은 용량성 부하를 구동하기 위한 고압 인버터의 노이즈 저감에 관하여 연구하였다. 이를 위하여 고전압 인버터의 전원이 되는 고 승압 컨버터와 용량성 부하를 구동할 수 있는 고압 인버터를 설계하고 실험했다. 고 승압 컨버터와 고압 인버터를 설계 후 컴퓨터 시뮬레이션으로 확인하였다. 설계된 고 승압 컨버터와 고압 인버터는 하나의 PCB로 제작이 되었다. PCB의 제작 시 노이즈 저감을 위하여 소자의 배치와 회로의 패턴을 설계 했다. PCB 제작을 통하여 노이즈 저감에 대한 강인성을 증대 시켰다.