• 전력전자학회논문지
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• 제25권3호
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• pp.162-170
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• 2020

In this paper, we report our study of the current measuring technique by implementing a pick-up coil in the PCB pattern instead of the current measuring sensor in a power converter using a WBG device. The proposed PCB pattern coil structure has a higher mutual inductance value than the conventional pattern by constructing the coil using the multi layer board. It has high sensitivity and is configured without additional process outside the PCB. In the current measurement, the integrator is measured by integrating the coil at the back end and the current waveform measured using proposed pick-up coil is confirmed by comparing it with the original current waveform through DPT simulation.

• 한국안전학회지
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• 제25권2호
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• pp.29-34
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• 2010

This paper is aimed to develop monitoring software for detecting the characteristics of current and voltage signals for series arc on electric wire. In order to attain this purpose, the characteristics of series arc were analyzed by the current and voltage signals on electric wire which were installed, and also analyzed by the changes of RMS, instantaneous of waveform value in time domain and THD in frequency domain. Monitoring program which analyze the signal was developed by Labview which can analyze in time domain and frequency domain, and save data. Experimental setup for detecting verification of monitoring program was composed loads of a lamp, an electric heater and an electric fan loads which were usually using. Measurement points for detecting verification of monitoring program were selected at both the panel board and the arc generator at the same time. As results of the experiments by monitoring program, the arc current waveform showed the same characteristic in all measurement points of all load. But the arc voltage waveform was different in each measurement point. When arc occurred, the THD of current value increased above 20%. The results of this study will be effectively used in developing the preventive system of electric fire by series arc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1005-1008
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• 1992

This paper deals with a method to Improve the input current waveform in a single phase Rectifier. This method is based on the sophisiticated utilization of the auxiliary circuit consisting of two SCRs and a interphase reacter and the condenser necessary for reducing the fluctuating voltage in output side. The basic theories of the proposed system is treated, and its validity is verified with simulation.

• 대한전기학회논문지
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• 제32권3호
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• pp.76-83
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• 1983

This paper describes the method of operating the phase controlled rectifier by controlling the firing angle in III, IV quadrant to absorb the lrading reactive power and of improving the waveform of ac current by driving dual converter. The system is intended to compensate the reactive power for any lagging load. Also, by the above method this paper enables us to improve the power factor and waveform referred to the source current and the dc output voltage in the converter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.501-504
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• 1997

We investigated the tracking and erosion resistance of the silicone rubber by Inclined-Plane Method. And. with the variation of experiment time, the chance of the leakage current waveform was evaluated. The typical leakage current waveform was the form of mixture of sinusoidal wave and rectifying wave. It is thought that the sinusoidal wave is due to conductivity of contaminant when wet. and the rectifying wave is due to arc of dry band.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.141-143
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• 2003

This paper proposes a new sensorless drive system for the trapezoidal Brushless Direct Current (BLDC) motor requiring mechanical position or speed sensor. The proposed method is using only one current sensor For this an indirect rotor position sensing method from the periodically variation DC Link current waveform. DC Link current waveform change from high to low when BLDC commutate status. This algorithm was verified by simulations using MATLAB SIMULINK and experiment.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.241-246
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• 2016

This paper presents a method that can improve the performance of permanent magnet synchronous motor current control by minimizing the measured current phase delay caused by the Low Pass Filter(LPF) used to cut off the noises that flowed in when feedback currents are measured. Although existing methods that change the Cutoff Frequency of the LPF can minimize phase delays during high speed rotations, their noise cutoff effects are much lower and this may lead to the decline of control performance. Therefore, in this study, an algorithm that can compensate current phase delays through relatively simple calculations from the synchronous motor d-q axis coordinate transformation matrix and the inverse transformation matrix is proposed and the validity of the proposed method is verified by comparing the waveform of the calculated current with the waveform of actual currents through simulations and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1876-1878
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• 1996

This paper describes the combination surge generator for applying performance tests of surge protective devices. The $8/20{\mu}s$ waveform applies to low impedance circuits and components and is commonly used to determine the characteristics of surge protective devices. And the $1.2/50{\mu}s$ waveform applies to high impedance circuits and components and is used for testing dielectric behavior. Therefore, the combination surge generator, which generates $1.2/50{\mu}s$ voltage waveform under open-circuit conditions and $8/20{\mu}s$ current waveform under short-circuit condition, was proposed. Also this generator can produce $10/1000{\mu}s$ as well as $0.5{\mu}s/100kHz$ ring waveform.

• 조명전기설비학회논문지
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• 제19권8호
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• pp.102-108
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• 2005

본 논문에서는 소프트 스위칭에 의한 새로운 고역률 승압형 AC-DC 컨버터가 제안되고 입력전류의 파형 및 고조파분석에 대해 상세히 해석된다. 시비율 일정의 전류불연속 제어에 의해 동작되는 제안된 컨버터의 입력전류는 교류 입력전압의 크기에 비례한 불연속적인 펄스열의 정현파 형태로 되어 입력역률을 개선시킨다. 또한 제안된 컨버터는 소프트 스위칭을 위한 공진동작에 의해 무손실 스너버 커패시터의 입력측 에너지 유입에 따른 역률증대의 효과를 가지며, 기존의 고역률 승압형 AC-DC 컨버터와 비교되어 입력전류의 수학적 분석과 컴퓨터 시뮬레이션, 실험결과 등에 의해 그 우수성이 입증된다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1131-1136
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• 2014

현재 LNG 운반선, 쇄빙선 등의 특수선박과 해양플랜트에 설치되는 전력변환 장치에는 다이오드를 이용하는 정류기가 많이 사용된다. 하지만 정류에 의한 비선형 부하의 입력전류에 많은 고조파가 포함되어 공급 전압파형의 왜곡을 초래한다. 전압파형의 왜곡은 발전기, 변압기, 부하기기 등의 오동작과 전력품질을 저하시키게 된다. 본 논문에서는 정류기 사용시의 전류왜곡을 감소시키기 위해서 직류 파형 정형화 회로를 사용하여 개선함으로써 부하에 인가되는 교류 파형을 정확한 정현파로 만든다. 그 결과 전력계통의 전류와 전압 파형에 포함되는 고조파를 저감할 수 있으며 이를 시뮬레이션을 통해 입증한다.