• Journal of international Conference on Electrical Machines and Systems
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• 제3권3호
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• pp.339-353
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• 2014

A straightforward method for optimal determining of a high frequency inductor's parasitic capacitance is presented. The proposed estimation method is based on measuring the inductor's impedance samples over a limited frequency range bordering on the resonance point considering k-dB deviation from the maximum impedance. An optimized solution to k could be obtained by minimizing the root mean squared error between the measured and the estimated impedance values. The model used to provide the estimations is a parallel RLC circuit valid at resonance frequency which will be transferred to the real model considering the mentioned interval of frequencies. A straightforward algorithm is suggested and programmed using MATLAB which does not require a wide knowledge of design parameters and could be implemented using a spectrum analyzer. The inputs are the measured impedance samples as a function of frequency along with the diameter of the conductors. The suggested algorithm practically provides the estimated parameters of a real inductance model at different frequencies, with or without design information. The suggested work is different from designing a high frequency inductor; it is rather concentration of determining the parameters of an available real inductor that could be easily done by a recipe provided to a technician.

• 대한전자공학회논문지TC
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• 제46권11호
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• pp.50-55
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• 2009

본 논문에서는 분포정수 회로합성을 이용하여 최적의 정전용량 흡수 능력을 갖는 분포증폭기를 설계한다. 증폭기를 구성하는 여파기의 전달함수는 저역통과 Chebyshev 근사로 합성하며, 이의 정전용량 흡수 능력은 최소 삽입손실(MIL)과 리플의 함수로 계산한다. 분포증폭기의 능동 소자는 S-퍼래미터를 이용하여 등가회로로 모델링하며, 이의 정전용량은 전달함수의 MIL과 리플을 적절히 조정함으로써 여파기 구조로 흡수한다. 이의 응용 예로써, 0.1~7.5GHz의 주파수 대역에서 약 12.5dB의 이득을 갖는 분포증폭기를 설계하며, 실험을 통하여 정전용량 흡수 능력을 고려한 분포정수 회로합성이 분포증폭기의 설계에 유용하게 이용될 수 있음을 입증한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권5호
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• pp.352-357
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• 2000

This paper presents about an example of circuit design and characteristics of inverter according to the variable capacitance of the DC voltage source separation capacitor used in ZVS-HB type high frequency resonant inverter. The soft switching technology known as ZVS is used to reduce turn off loss at switching. In the event the capacitance of the DC voltage source separation capacitor is varied, the analysis of inverter circuit has generally described by using normalized parameter and operating characteristics have been evaluated in terms of switching frequency and parameters. According to the calculated characteristics value, a method of the circuit designs and operating characteristic of the inverter is also presented in this paper. In addition, this paper proves the validity of theoretical analysis through the experiment. This proposed inverter shows that it can be practically used in future as power source system for the lighting equipment of discharge lamp, DC-DC converter etc.

• 한국정보통신학회논문지
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• 제20권1호
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• pp.175-184
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• 2016

본 논문에서는 기존의 LCR 미터에 의한 측정방식이 아니라 C/V(capacitance to voltage) 변환 방식을 이용하여 커패시턴스를 측정하는 방법을 제안하였다. 그리고 다중채널용 초음파 프로브 진단장치를 구현하기 위해 192채널들을 6개의 MUX(multiplexer) 채널로 변환하는 아날로그 MUX 회로를 설계하였다. 각각의 MUX 채널 회로별 전압을 다시 커패시턴스로 변환하는 회로특성이 다르기 때문에 각각의 MUX 채널별 디지털전압을 커패시턴스로 변환하는 변환함수를 최소 자승법을 이용하여 유도하였다. 개발된 시제품의 성능시험결과로 1회 측정시간이 4초 이내로 측정되었고, 192개 채널들의 반복적인 측정에서 최대값, 최소값, 평균값에 대한 측정 오차값이 5% 이내의 시험결과가 제시되었다.

• 전기전자학회논문지
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• 제18권1호
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• pp.31-36
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• 2014

본 논문에서는 트랜스포머의 자가공진 특성에 대하여 분석하였으며, 부유용량과 권선량, 권선비에 따른 변화관계를 수식으로 정리하였다. 일반적으로 트랜스포머에서의 부유용량은 제작과 관련하여 불요인자로 간주되나, 모든 트랜스포머에서 내재하는 특성을 갖는다. 특히 고역의 구동 주파수에서는 해당 특성이 확연하게 나타남은 주지의 사실이며, 자기적 요소와 결합하여 특정주파수에서 공진형상을 유발한다. 출력이득 값이 높아야 하는 소형 고전압기기, 특히 의료용 응용전기기의 경우 트랜스포머의 자가공진 특성을 이용하면 트랜스포머 및 회로의 사이즈를 줄임과 동시에 시스템의 경량화가 가능하여 추가적 설계 기법으로 제안한다.

• 한국해양공학회지
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• 제10권3호
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• pp.162-167
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• 1996

This paper deals with an implementation method for the one chip microprocessor(8097)-based capacitance type wave recorder for a measuring real-time wave height. The system was developed to make it possible to real-time remote sensing the wave height by deploying the RS-232/422/485 communication methods. The system test results for the developed system such as linearity, system stability and robustness of the disturbance was also verified through the performance tests of the system. Furthermore, the system was developed after due consideration with connecting the public network such as satellite mobile communication system and LAN, through the deploying VLSI(Very Large Scale Integration) design techniques.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.249-252
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• 2003

본 논문에서는 반도체 방식의 직접 터치식 capacitive type 지문인식센서의 신호처리를 위한 회로를 제안하였다. 센서로부터의 capacitance의 변화를 전압의 신호로 전환하기 위해서 charge-sharing 방식의 회로를 적용하였다. 지문센서 감도저하의 가장 큰 원인인 sensor plate에 존재하는 parasitic capacitance를 제거하여 ridge와 valley 사이의 전압차를 향상시키기 위하여 기존과는 다른 아날로그 버퍼회로를 설계 적용하였다. 센서 하부회로와의 isolation 대책을 통하여 ESD 및 노이즈방지를 위한 설계를 실시하였다. 제안된 신호처리회로는 128$\times$144 pixel 규모의 회로로 구현되었다. 본 설계회로는 향후 생체인식을 이용한 정보보호용 지문인식 시스템에 응용될 수 있으리라 본다.

• 전기학회논문지
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• 제60권10호
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• pp.1972-1977
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• 2011

The mechanical integrity of generator stator windings is one of the critical point because the electric power is generated and conducted to power system through these windings. To cool down the heat emitted from generator winding during its operation, a majority of generators use de-mineralized water characterized by high cooling efficiency. Contrary to such the excellent cooling efficiency, however, the damaged bar insulations attributed to the absorption of cooling water in the generator stator winding lead to highly time- and cost consuming efforts as well as to service deterioration due to unexpected forced outage of generator. It is described that the new design of water absorption sensor using cross capacitance for generator in power plant in order to increase the reliability of water absorption diagnostics for generator stator bar insulation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권1호
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• pp.20-26
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• 2005

Various kinds of practical machines using the single phase induction motor (SPIM) are utilized to control both speed and torque. In particular, the capacitor-run type SPIM has the characteristic that allows the motor torque to be altered by auxiliary capacitance variation. In this study, we manifest an equivalent model having a more simplified configuration, and clarify the relationship between torque and capacitance. Also, we design an experimental controller that is able to perform speed control with ease by the phase angle control of the AC input voltage. Validity of this study is confirmed through the simulation and experimental results obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.550-553
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• 2001

In this study, unity current gain frequency f$\_$T/ of GaAs MESFET is predicted with different temperatures up to 400 $^{\circ}C$. Temperature dependence parameters of the device including intrinsic carrier concentration n$\_$i/ effective mass, depletion width are considered to be temperature dependent. Small signal parameters such as gate-source, gate dran capacitances C$\_$gs/ C$\_$gd/ are correlated with transconductance g$\_$m/ to predict the unity current gain frequency. The extrinsic capacitance which plays an important roles in high frequency region has been taken into consideration in evaluating total capacitance by using elliptic integral through the substrate. From the results, f$\_$T/ decreases as the temperature increases due to the increase of small signal capacitances and the mobility degradation. Finally the extrinsic elements of capacitances have been proved to be critical in deciding f$\_$T/ which are originated from the design rule of the device.