• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.175-177
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• 2003

Because the overhead transmission lines arc exposed to the outdoor weather, the faults of the transmission lines are due to natural conditions, and among these faults, the outage rate by lightning is about 50%. The lightning causes the damage of power system equipments, the shut down of electricity and the electro-magnetic interference. Therefore, the pertinent insulation design is important, not only to decrease the damage of the facility itself but also to increase the reliability of electric power system. For these reasons, we have to obtain and accumulate the lightning current parameters for the basic lightning research. This paper describes the development of real time analysis system about lightning information.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.509-511
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• 2003

Because the overhead transmission lines are exposed to the outdoor weather, the faults of the transmission lines are due to natural conditions, and among these faults, the outage rate by lightning is about 50%. The lightning causes the damage of power system equipments, the shut down of electricity and the electro-magnetic interference. Therefore, the pertinent insulation design is important, not only to decrease the damage of the facility itself but also to increase the reliability of electric power system. For these reasons, we have to obtain and accumulate the lightning current parameters for the basic lightning research. This paper describes the statistical distribution of lightning current parameters and the IKL map.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.126-133
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• 2016

This paper proposes a new PWM method to reduce the common mode voltage change in three-level Vienna rectifier. This new proposed PWM method uses medium voltage vector for the three-level Vienna rectifier to determine the sum of three-phase voltage zero, and the common mode voltage variation is decreased. Using the carrier comparison method, the switching function generator for three-level Vienna rectifier has been proposed. The effects of the proposed PWM method have been verified through simulation using the PSIM.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1546-1547
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• 2006

오늘날 전자기파의 영향은, 제어장비의 내부에 있는 기판의 전자 부품에 전자기적인 충격을 주어 장비의 오동작이나 고장을 일으키는 등 심각한 문제들이 제기 되고 있다. 이러한 임펄스 전자기파는 제어 장치에 연결된 제어전선으로 타고 들어와서 전자장비 내부의 부품들과 반사,공진등을 일으켜서 결국에는 PCB(printed circuit board)에 손상을 입혀서 그 장치들을 사용 못하게 할 수가 있다. 주파수가 광대역인 50MHz 에서 800MHz 까지의 EMI(electro magnetic interference)환경을 만들 수 있는 장치를 제작 하였다. 이러한 UWB(ultra wide band)장치는 고전압펄스를 압축 성형하여, 동작시간이 아주 빠른 ultra fast 스위치를 통해서, 펄스의 기림 시간이 수백ps의 파형을 만들어, 안테나로 전송하여 공간으로 방사시키는 장치에 대해 설계 제작하여 실험한 결과에 대해 논하고자 한다.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.147-151
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• 2002

액정표시장치(LCD; Liquid Crystal Display)는 표현된 정보를 가시화하기 위해 램프의 백라이트가 필수적인데 대부분 부피가 작고 효율과 휘도특성이 좋은 냉음극 방전램프가 사용된다. 램프는 고압으로 구동되며 높은 전압을 얻기 위해 일반적으로 권선 변압기를 사용한다 그러나 권선 변압기의 경우 자체의 철심이나 권선의 손실로 인하여 출력 효율의 한계가 있으며, 고압을 위해 감긴 코일은 부피를 크게 하며 무겁게 만든다. 이를 해결하기 위해 본 논문에서는 변압기 자체 손실을 줄이고 소형화가 가능하며 높은 승압비을 가진 PAN-PZT계의 적층형 압전 변압기를 제작하였으며, 회로의 손실을 줄이기 위한 영전압 스위칭(ZVS; Zero Voltage Switching)과 그리고 LCD패널과 인버터의 불필요한 간섭현상(EMI; Electro-Magnetic Interference)을 줄일 수 있으며 소형화가 가능한 풀 브리지형 압전 인버터를 설계하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.579-588
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• 1999

This paper presents a technique for predicting the conductLu EMI(Electro Magnetic Interference) produced b by PWM inverter-induction motor drive system. To obtain the simulation models for prediction of conduct떠 n noise, high frequency model of an inverter leg with parasitic elements and multi-coil model of stator winding M are designed. Finally, the results are confirmLu from simulation and experiments.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.277-278
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• 2012

본 논문은 고조파(Harmonics) 규제 만족을 위해 사용되는 리액터와 EMI(Electro-Magnetic Interference) 필터 회로에 관한 것으로서, 기존의 고조파 규제와 150kHz ~ 30MHz 대역의 EMI CE(Conducted Emission) 규제를 만족하기 위하여 각각 사용했던 리액터와 EMI 필터의 CM Choke 코일을 CM Choke의 누설 인덕턴스를 이용하여 CM Choke 코일 하나로 대체한다. 결과적으로 기존의 리액터 소자를 제거함으로써 사용 소자 개수 저감에 따른 부피 및 가격 저감을 실현할 수 있다는 장점을 가진다. 또한 실제 제품에 적용해 고조파, EMI 측정결과 문제가 없음을 검증하였으며, 온도 특성도 문제가 없음을 확인했다.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.544-548
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• 2008

Typically electronic resistance type sensors have been used for measurement system of high-speed trains. But due to a large number of measurement quantities, we had difficulties in installing and maintaining the cables that connect sensors and measuring devices. Furthermore, signals obtained from the electronic resistance type sensors are often distorted because the sensors and cables are vulnerable to electro-magnetic interference (EMI). In this paper the characteristic of FBG sensors are compared with those of electronic resistance type sensors in application for the measurement system of high-speed trains. FBG sensors have advantages because of their multiplexing characteristic and robustness to EMI environment.

• Korean Journal of Acupuncture
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• v.21 no.2
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• pp.1-28
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• 2004

Objectives : Human physiological changes in the state of qigong has been measured using EEG(Electroencephalography), functional MRI(functional Magnetic Resonance Image), EAV(Electro-Acupuncture according to Voll) and SQUID(Superconducting Quantum Interference Device) measurements. Methods & Results : EEGs were measured to study the differences between Qigong masters and Qi receiver on the changes of EEG. During Qigong, an alpha waves were increased. The power spectra indicate that the peak frequency of alpha waves increased during Qigong. Qi receiver's EEG signals seemed to affected by the state of himself. Brain activation did not observed when qigong master concentrates the Qi at Laogong(P8). But a localization of fMRI signal in the sensory cortex was observed by electric acupuncture stimulation at Laogong(P8). Five phase deviation of EAV were clearly changed in the both cases of Qigong master and Qi receiver. When a Qigong master concentrates the Qi at Yintang, Laogong(P8), Qihai(CV6) meridian points during Qigong state, the change of magnetic field around acupoints Yintang, Laogong points has been measured using 40-Channel DROS-SQUID apparatus. After smoothing process of the continuously measured magnetic signal around acupoints for a few minutes, we could observe that a series of peaks, magnitude of -1.0~2.5pT appeared. But there was no significant difference in changes of magnetic signal around acupoints. Physical signals of magnetocardiogram has been measured by using 2-Channel DROS SQUID(Magnetocardiogram). Physical signals of magnetocardiogram were clealy changed at the ST segments after S-wave when qigong master concentrates the Qi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1172-1182
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• 2014

In these days, many kinds of goods are more light and more integrated. As frequency range of mobile applications have increased to improve performance of antenna furthermore, EMI(ElectroMagnetic Interference) problem has frequently caused by disturbance of antenna in device which aggravates other circuit. This paper proposes a technique for the prediction of noise power to the transmission line from antenna located near the line. Although noise power transferred to transmission line is varied by source impedance of antenna and load impedance of transmission line basically, the power magnitude can be presented in a square form of S-parameter between antenna and transmission line due to small variation of transferred power. For this reason, we can use the index expressed the transferred power varied along geometrical shapes of transmission line. As a result, big difference is occurred along location of antenna especially the bended line. And this such experiment is correspond with simulation, these results have meaning physically considering electromagnetic field distribution in near and far field. HFSS of Ansys and CPW with ground is used in this paper.