• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.196-201
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• 2008

This paper is about electromagnetic vibration source in outer rotor type of BLDC motors. Experiments are carried out with three pole-slot combinations which are 6 slots, 12 slots, and 24 slots with 4 poles rotor. According to results, vibration sources separate into electromagnetic and mechanical factors. Using the finite element method (FEM), It is analyed that vibration characteristics of electromagnetic source in each type. This paper shows electromagnetic sensitivity to vibration, and introduces necessary point in lower vibration motors. Also rotor balance is important to prevent uneven distribution of magnetic flux between rotor and stator.

• Journal of electromagnetic engineering and science
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• 제9권2호
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• pp.53-60
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• 2009

Remarkable developments in the electric and electronic industry have given people's daily life much more convenience and abundance. However, in electrical communication, or electric and electronic fields, making electrical and electronic devices more functional, more integrated, and faster have put electromagnetic interference(EMI) into more complex forms, and lots of problems such as interruption, malfunction, or interference by noise between electrical communication systems occurs every day. In this research, the electromagnetic compatibility(EMC) filter in the high powered breaker was designed and fabricated as a counter measure. The filter attenuated noise more than 20${\sim}$50 dB in the range of 10 MHz${\sim}$1.5 GHz. And, when the electric fast transient(EFT) of 4 kV in the level 4 of IEC 61000-4-4 was induced, it was soon suppressed to 600 V.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.569-576
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• 2014

There were overwhelming high-frequency electromagnetic noises in 200kW-class hybrid electric vehicle(HEV) although EMC control strategy had been applied to cope with the electromagnetic noises during the development of HEV. This paper investigates the characteristics of the conducted and radiated emission noises, the source and path of noises, and the effects of EMI on the electronics. Finally the design concept of noise control is proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.936-939
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• 2006

The pneumatic isolator is widely adopted for anti-vibration of precision measuring and manufacturing equipments. But, when the precision demand on anti-vibration is extreme or the load is moving, the performance of anti-vibration can not meet satisfaction. In these cases, as a complementary, active vibration suppression system can be added for advanced performance. In this paper, an active control system is presented, which uses electromagnetic actuators for vibration suppression. The anti-vibration characteristic of pneumatic isolator is analyzed for system modeling and actuator specifying. The modeling and the 3D dynamic simulation is performed for control system design. For the electromagnetic actuator design, the magnetic flex density and the current-force characteristic analysis are achieved.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.812-821
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• 2018

An electromagnetic excitation force is caused by the air-gap flux density, which greatly influences the noise and vibration of the motor. In many real projects, skewed slot technology is widely used to reduce the harmonic components of the air-gap flux density to reduce the noise and vibration of the motor. However, a skewed slot has several side effects such as a transverse current and axial drifting. Thus, a double skewed slot rotor is selected with the aim of eliminating these side effects. This paper presents the exact structure of the double skewed slot rotor and the mechanism whereby the electromagnetic excitation force can be reduced. A multi-slice method is adopted to model the special structure. Finite element simulation is used to verify the theory.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.68-71
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• 2001

This paper has been studied for a comparison of the propagation and noise characteristics between ultrasonic and electromagnetic wave for the high speed communication of the short range telemetry. We analyze the propagation depth of electromagnetic and ultrasonic wave by skin depth effect and by ultrasonic loss ratio. We also studied several effects such as near field effect in electromagnetic wave and Rayleigh scattering noise of ultrasonic wave, etc. We show the experimental results of their propagation loss and modulation experiments in water. The experimental results show that both method is good for the implementation of short range telemetry.

• 전기전자학회논문지
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• 제22권2호
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• pp.510-513
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• 2018

최근 전자파 적합성(EMC: electromagnetic compatibility)의 중요성이 매우 높아짐에 따라 칩 수준에서의 전자파 간섭(EMI: electromagnetic interference) 측정이 자주 요구되고 있다. IEC 61967 및 IEC 62508에서 규정된 근거리 전자장 스캐닝(NFS: near-field scanning) 시스템은 칩 레벨에서의 전자파 간섭을 분석하는 대표적인 방법이다. 칩이 점점 고속화되면서 근거리 전자장 스캐닝 시스템의 측정 주파수는 광대역화되어야 하지만 근거리 전자장 탐침(NFP: near-field probe)의 신호 대 잡음 비(SNR: signal-to-noise ratio)가 저하된다는 문제가 있다. 본 논문에서는 근거리 전자장 스캐닝 시스템에서 광대역 특성을 가지면서도 잡음 대 성능 비를 향상시키는 기술에 대해 살펴본다.

• 한국전자파학회논문지
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• 제9권6호
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• pp.850-859
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• 1998

AC 전원선로에서 발생하는 수 KHz에서 수십 MHz에 이르는 광대역의 주파수특성을 가진 전원노이즈는 전기, 전자, 통신장비의 정상적인 동작에 많은 장해요소가 되고 있으며 이들 전도성 노이즈를 억제하기 위한 기기로 기존에는 써어지 억제기와 필터가 적용되어 왔다. 그러나, 이러한 기존의 노이즈 대책기기는 전력 공급선과 노이즈 피해회로 상호간의 전기적인 절연 분리가 원천적으로 불가능하므로 전도성 노이즈 중에서 가장 큰 피해를 끼치는 공통모드노이즈 억제성능이 지극히 제한적이다 따라서 본 논문에서는 전원회로의 공통 모드 및 정상모드 노이즈억제에 사용 가능한 NCf(Noise Cut Transformer)에 대한 모의 등가회로를 제안하였으며, 계산과 실험을 통해 그 성능을 비교 해석함으로써 모의 해석이 타당함을 입증하였다, 또한 절연 변압기 와 설계 제작된 시작품 빛 노이즈 펼터와의 성능을 비교함으로써 전도성 노이즈 억제성능의 우수성을 검증하였다.

• 한국소음진동공학회논문집
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• 제22권3호
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• pp.208-213
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• 2012

With great advancement of the automobile functions, environmental factors become important performances, especially noise. This paper investigates noise sources of outer rotor type BLDC motor using in the air-conditioner of the automobiles. To this end, this paper is analyzed two viewpoints, structural and electromagnetic causes. Structural analysis is conducted through modal test and analysis. For modal analysis, 3D finite element analysis is carried out using commercial program ansys. Electromagnetic causes are analyzed from local force that is computed by Maxwell stress tensor method. Local force excites structure of motor directly. Finally, correlation analysis is performed to determine effect between noise causes.

• 한국전자파학회논문지
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• 제12권6호
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• pp.865-870
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• 2001

이 논문에서는, PLL주파수 합성기의 VCO로부터의 위상잡음이 64 QAM 시스템 성능에 미치는 영향을 분석하려 한다. 발진기에서 발생하는 위상잡음을 실제와 유사하게 예측하기 위해 발진기의 입력 충격 전류가 소신호일 때를 가정하여 선형 시변(linear time-varying : LTV) 모형을 고려하였으며 64 QAM 시스템에서 위상잡음이 복조부에서 검출과정을 거칠 때 위상잡음이 없는 백색정규잡음 환경에서의 BER과 비교하여 어느 정도 시스템 성능을 떨어뜨리는지를 분석한다.