• Journal of Power Electronics
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• 제19권2호
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• pp.403-412
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• 2019

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

• 한국정보전자통신기술학회논문지
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• 제16권2호
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• pp.104-108
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• 2023

최근 전기 차 시장의 확대로 인해 성능 및 안정성 문제를 보완할 친환경적인 전기 차 시장이 매우 커지고 있다. 전기 차의 화재 등 여러 안전 문제를 일으키는 전장 부품의 연동으로 인한 EMI 문제는 매번 대두되어 지고 있다. 다양한 기술들을 결합하여 최적의 충전효율을 달성하고 무선 충전 컨트롤 모듈에서 발생하는 EMI 잡음을 줄이기 위해 노력하고 있다. 본 논문은 전기자동차의 중요한 부품 중 하나인 무선충전컨트롤 모듈의 EMI 잡음 중 방사성 잡음 저감 기술을 설계하여 실험을 하였다. 무선 충전 컨트롤 모듈에서 발생하는 EMI 문제를 분석하기 위해 Ansys 시뮬레이션 툴 내 Python 기반 스크립트 기능을 활용하여 치명적인 요인에 대한 축적된 시험 데이터를 학습시켜 강화 학습을 통한 최적화 설계 기술을 적용하여 최적화된 무선충전컨트롤 모듈은 일반적인 무선충전 컨트롤 모듈 대비 25dBu V/m의 EMI 잡음 개선 효과를 보였다. 이러한 결과는 전기 자동차에서 더 안정적이고 신뢰성 높은 무선 충전 기능의 개발에 기여할 뿐만 아니라, 이를 통해 전기자동차의 사용성과 효율성을 높이며 환경친환적인 대안으로 자리 잡을 수 있게 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.53-56
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• 2000

An Electrical equipment is the noise source which makes a noise. So the optimally designed filter should be inserted in the equipment in order to reduce the noise. The noise source impedance is varied according to the frequency It effects on the CE noise. Knowing the magnitude of its impedance and inserting an EMI filter in the equipment we can estimate the insertion loss of the filter. SO it helpful in designing the EMI filter. The measurement method of a noise source impedance is proposed and verified by experiment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.811-814
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• 2004

Radiated noise from high frequency transformers (HTFs) of switching mode power supply is mainly caused by the leakage inductance and the parasitic capacitance of HTFs. Generally, the radiated noise can be reduced by adding snubbers to switching power circuits or shielding HTFs. Radiated noise, however, is mainly affected by the shielding method. In this paper, the various shielding methods to reduce the radiated noise of EMI are analyzed, compared in the experimental studies. And it is proved that the radiated noise can be reduced according to the shielding methods of HFTs and the electrical connection between shields and power circuit.

• 대한전기학회논문지:전력기술부문A
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• 제51권1호
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• pp.23-28
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• 2002

In order to survey the radiation characteristics of pure line noise of unwanted noise from overhead high voltage AC transmission lines, a disk type gap noise generator was manufactured. Disk size which decides capacitance between the noise generator and earth was selected through preliminary indoor experiments and analysis by using surface charge method. The capacitance is one of principal parameters related to the injection of a proper noise current into lines. On the basis of the capacitance obtained from calculation, 5mm of space was given to the gap of the noise generator to be installed o test line and an aluminum disk of 60cm radius was made. The field experiments were performed with the noise generator hung on the Kochang 765 kV full scale test line. As the results, the useful data which can be used to analysis the radiation characteristics of noise from transmission lines were obtained. Those are the directivity of antenna toward the line, lateral profiles, frequency spectra, height pattern and so on.

• 전력전자학회논문지
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• 제9권3호
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• pp.260-266
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• 2004

EMI필터는 주로 시행착오 법에 의해서 설계하기 때문에, 전력변환기기의 전도 EMI를 감쇠시키기 위해서는 많은 시간을 요하게 된다. 따라서 본 논문에서는 이러한 문제를 극복하기 위해서 EMI 필터에 대한 새로운 분석적인 설계절차를 제안한다. 각 부품에 대한 고주파 모델을 구성하고, 이러한 모델링 회로를 이용하여 각 모드에 적용할 수 있는 필터를 설계한다. 실제 사용되는 부품에 대한 축적된 데이터 베이스와 표준필터를 적용한 EUT(Equipment Under Test)의 측정 데이터를 기초로 해서 필터를 설계하는 알고리즘을 제안한다. 끝으로, 측정결과를 통해서 제안된 모델과 설계방법의 타당성을 확인한다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.211-214
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• 2007

Development of IT and electronics industries has make our life more convenient, yet at the cost of radio communication noise, malfunctioning of electronic appliance and risks against human health all resulting from EMI. Many states are tightening their EMI (Electro Magnetic Interference) regulations around the world and the EMI regulatory measures are likely to increase in terms of targets and types. Against this backdrop, this paper aims to introduce fundamental and adequate EMI countermeasures encompassing product production cycle from design to production stage.

• 한국전자파학회논문지
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• 제26권9호
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• pp.798-805
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• 2015

본 논문에서는 랜덤 수 생성 회로를 통해 Relaxation Oscillator의 주파수를 불규칙하게 변환하여 EMI Noise를 최소화하는 방법을 제시한다. 또한, DC-DC Converter에 이 기법이 적용되었을 때의 효과와 이 결과가 RF Receiver system에 미치는 효과를 Noise 측면에서 연구하였다. 제안하는 Relaxation Oscillator 출력 중심주파수는 7.9 MHz이고, 온도보상기법을 적용하여 온도변화에 따라 주파수가 보상되도록 설계하였다. 이 칩은 $0.18{\mu}m$ 공정으로 설계하였고, 칩의 면적은 $220{\mu}m{\times}280{\mu}m$이다. 전류 소모는 공급전압인 1.8 V에서 $500{\mu}A$이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1881-1884
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• 2003

In some requirements of dc motor drive circuit applications are high quality output with generation of low internal conducted EMI. However the conventional dc motor drive circuits have been usually using unbalanced circuit which generates the high conducted EMI to the frame ground. This paper presents a balanced dc motor drive circuit which is effective way to reduce the common-mode noise. The circuit balancing is to make the noise pick up or occurring in both conductor lines, signal path and return path is equal in amplitude and opposite phase so that it will cancel out in the frame ground. The common-mode conducted noise reduction of this proposed dc motor drive is confirmed by experimental results.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.69-74
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• 2004

In general the surge pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the surge pressure, high frequency PWM control of 20KHz was attempted. To estimate the braking noise caused by surge, a vehicle equipped with on-board ABS hydraulic modulator has been experimented with respect to the various breaking condition. Thorough this experiments, it was found that breaking noise has been reduced using high frequency PWM control method compare with low frequency method. To evaluate high frequency control m practice, including verification of general functionality, EMI tests was experimented. Its was found that it is necessary to have the solution to electromagnetic interference(EMI) generated by switching elements.