• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
• /
• pp.301-304
• /
• 2002

This paper has been studied an A/D conversion system for precision weighing signal process In weighing system. A/D conversion has some problem.; offset drift voltage with environment situation and nonzero value of initial output voltage. The Offset voltage in analog circuit produces a drift of an output voltage before A/D conversion stage. This paper suggested the method of reducing the offset voltage by switching analog chopping circuit and making the initial output close to zero to enhance the swing range by D/A converter. Also, we have designed active filter and digital filter with Auto Zero Tracking algorithm for better signal process of the weighing system.

• 한국공작기계학회논문집
• /
• 제17권3호
• /
• pp.65-70
• /
• 2008

Capacitive position sensing with modulation technique is widely used in electrostatic actuator applications. To maximize the electrostatic force and the position-sensing gain, capacitors for driving and capacitors for sensing are shared, i.e, after applying the driving voltage with high-frequency modulating signals using op amps, the position is demodulated from the modulated signal. In high-voltage applications, however, low bandwidth of a high-voltage op amp hinders adding the high-frequency modulating signal to the driving voltage. In this paper, new and very simple driving and sensing method is proposed, in which the pulse-width modulated driving voltage eliminates the need of the high-frequency modulating signal for position sensing. This new algorithm is proved by the simulation results using Matlab/SIMULINK.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.323-326
• /
• 2001

This paper describes the algorithm which can not only take account of voltage suability but also consider small signal stability. As for voltage stability both CPF and PoC methods are utilized to pinpoint the exact voltage collapse point. Then, using the converged load flow results full system matrix is configured and its eigenvalues are computed. The suggested algorithm is applied to the Two-area system, and verified its usefulness. In addition this paper also deals with the results of analyzing the two-area system in terms of voltage stability and small signal stability.

• 조명전기설비학회논문지
• /
• 제27권5호
• /
• pp.81-88
• /
• 2013

A low voltage circuit breaker protects electrical equipments from over current and short faults of system by cutting the power supply. The breaker use a thermal magnetic type trip device from the past. In recent years, electronic type relays are applied due to useful functions and services. The purpose of this development is full digitalizing of relay functions of a low voltage breaker. It includes separation of current sensor from current transformer, digital signal processing, high speed relaying, and voltage measuring for power meter. The suggestions are tested and implemented by making prototype and testing its all relay functions.

• 대한전자공학회논문지SD
• /
• 제41권3호
• /
• pp.109-114
• /
• 2004

본 논문에서는 반도체 방식의 직접 터치식 용량 형 지문인식센서의 신호처리를 위한 회로를 제안하였다. 센서로부터의 용량의 변화를 전압의 신호로 전환하기 위해서 전하분할 방식의 회로를 적용하였다. 지문센서 감도저하의 가장 큰 원인인 센서 플레이트에 존재하는 기생용량을 제거하고 융선과 계곡 사이의 전압차를 향상시키기 위하여 기존과는 다른 아날로그 버퍼회로를 설계 적용하였다. 센서 하부회로와의 isolation 대책을 통하여 ESD 및 노이즈방지를 위한 설계를 실시하였다. 제안된 신호 처리회로는 0.35마이크론 표준 CMOS 공정에 의해 레이아웃 되었다.

• Journal of Electrical Engineering and Technology
• /
• 제9권4호
• /
• pp.1210-1216
• /
• 2014

This paper deals with an application of Teager Energy Operator (TEO) and Energy Separation Algorithm(ESA) to detect and determine various voltage waveform distortions like harmonics, inter-harmonics and frequency variation. Because the TEO and DESA algorithm was initially proposed for speech or communication analysis, its applications are limited to some types of waveform in the power quality analysis area. For example, an undistorted voltage signal is similar with a pure sinusoid. A voltage fluctuation is very similar with an amplitude-modulated signal, from the viewpoint of signal theory. And a continuous frequency variation is similar with a frequency-modulated signal, which is also known as a chirp signal. This paper is written to show that the TEO and DESA algorithm can be used for detecting occurrences of the representative waveform distortions and determining their instantaneous information of amplitude and frequency.

• 센서학회지
• /
• 제5권6호
• /
• pp.25-34
• /
• 1996

본 논문에서는 압저항형 압력센서를 위한 신호처리회로를 설계하였다. 신호처리회로는 압저항형 압력센서를 구동하기 위한 기준전압 회로와 미소한 센서 신호의 증폭을 위한 인스트루먼트 증폭기로 구성이 되어있다. 신호처리회로는 단일 폴리 이중 메탈(single poly double metal) $1.5\;{\mu}m$ BiCMOS 공정 파라미터를 이용하여 HSPICE로 시뮬레이션 하였다. 시뮬레이션 결과, 밴드갭 기준전압회로의 온도 계수는 $0\;{\sim}\;70^{\circ}C$의 범위에서 $21\;ppm/^{\circ}C$였고 PSRR은 80 dB였다. BiCMOS 증폭기의 이득, 옵셋, CMRR, CMR, PSRR, 특성은 CMOS나 바이폴라보다 우수하였고 전력소비 및 잡음전압 특성은 CMOS가 우수하였다. 설계한 신호처리 회로는 옵셋이 적고 입력 임피던스가 높으며 CMRR 특성이 우수하기 때문에 센서 및 계측용 신호처리회로로서 사용하기에 적합하다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 춘계학술대회 논문집
• /
• pp.130-134
• /
• 1996

The characteristics of AE(Acoustic Emission) signal is related to cutting conditio, tool material, and tool geometry in metal cutting. The relation between AE signal and tool life was investigated experimentally. Experiment is carried out by gear shaping and SCM 420 workpiece. AE RMS voltage were increased according totool wear. It is suggested that maximum value of AE RMS voltage is an effective parameter to monitor tool life.

• 대한전자공학회논문지SD
• /
• 제48권11호
• /
• pp.41-47
• /
• 2011

산업용 표준 센서 신호처리를 위해 다양한 입력신호를 5V 전압 출력으로 변환하는 새로운 디지털 계측 증폭기(DIA)를 설계하였다. 이 계측 증폭기는 상용의 계측증폭기, 7개의 아날로그 스위치, 2개의 1.0V와 -10.0V의 기준전압, 그리고 4개의 저항기로 구성된다. 신호 변환원리는 입력신호에 따라 저항기와 기준전압을 디지털적으로 선택하여 5V의 출력전압을 얻도록 회로 구성을 바꾸는 것이다. 시뮬레이션 결과 DIA는 0V~5V, 1V~5V, -10V~+10V, 그리고 4mA~20mA의 입력신호에 대하여 우수한 0~5V 출력전압 특성을 얻을 수 있다는 것을 확인하였다. 4가지 입력 신호에 대하여 비선형오차는 0.1%이하이다.

• 전력전자학회논문지
• /
• 제19권5호
• /
• pp.407-414
• /
• 2014

This study proposes a control design for the grid output current and for reducing the neutral-point voltage oscillation through the small-signal modeling of the three-phase grid connected with a three-level neutral-point-clamped (NPC) inverter with LCL filter. The three-level NPC inverter presents an inherent problem: the neutral-point voltage fluctuation caused by the neutral-point current flowing in or out from the neutral point. The small signal modeling consists of averaging, dq0 transformation, perturbing, and linearizing steps performed on a three-phase grid connected to a three-level NPC inverter with LCL filter. The proposed method controls both the grid output and neutral-point currents at every switching period and reduces the neutral-point voltage oscillation. The validity of the proposed method is verified through simulation and experiment.