• Title/Summary/Keyword: Electric noise

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Noise Reduction of Electric Vehicle using Passive Damping Material (수동형 패치를 이용한 전기차 소음 저감)

  • Kim, Hyunsu;Kim, Byeongil;Han, Won-ok
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.6
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    • pp.117-122
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    • 2017
  • Cabin noise due to the electric powertrain of electrical vehicle may consists of motor noise caused by electrical mismatch and gear noise coming from reduction gearbox. These sound may be considered rather small noise compared to those of internal combustion engine, but without masking effect, the noise can be more annoying for customer. Thus, this paper demonstrates the characteristics of electrical vehicle powertrain noise, and the effect of passive damping material for the noise reduction. The typical motor noise can be affected by the motor torque. Also, it is demonstrated that the reduction gearbox may be a weak point for the noise path compared to the motor housing. With vehicle test, it is shown that the damping patch is more effective for noise reduction with deceleration condition than with acceleration condition.

A Study of Electromagnetic Interference in Power Line Communication (전력선 통신에서의 전자파 장해에 관한 연구)

  • Lee Jin-Taek;Chun Dong-Wan;Park Young-Jin;Lee Won-Tae;Shin Chul-Chai
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.12
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    • pp.620-625
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    • 2004
  • In this paper, we studied the emissive electric field due to the communication signal and the noise in medium voltage power-line. There are many types of conductive noise in power-line channel, which gives rise to radiation. And if the DMT carrier signal was excited, the current by this term was added to the current by noise and, generate radiation. We calculated input impedance by means of signal input network model of medium voltage power-line channel for calculating these currents. We calculated currents by input impedance and, calculated the emissive electric field by this calculated currents. From the measurement results, we knew that the measured results are very similar to the calculated results and if the input signal power level was higher than -40 dBm, the emissive electric field exceeds FCC radiation limit level 69.5 dB$\mu$V/m.

Analysis on behavior of MLCC considering material properties for BaTiO3 (Barium Titanate 의 재료 특성을 고려한 MLCC 의 거동 분석)

  • Park, No-Cheol;Jeong, Sanggeuk;Ko, Byeong-Han;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.69-71
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    • 2014
  • MLCCs are used broadly in electronic industry like smart phone and TV. Although they are fabricated in small size and have high capacitance, there are acoustic noise problems to reduce comfort of user. Acoustic noise results from linear piezoelectricity and nonlinear electrostriction of $BaTiO_3$ in MLCC and there are some researches on MLCC vibration under AC electric field. When only AC electric field without DC bias is applied to MLCC, fundamental frequency response is affected by piezoelectricity and second-harmonic frequency response shows electrostrictive vibration. In this study we get vibration shape of MLCC under AC electric field for each frequency and analysis on the mechanism of MLCC vibration affected by piezoelectricity and electrostriction.

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KERNEL-BASED NOISE FILTERING OF NEUTRON DETECTOR SIGNALS

  • Park, Moon-Ghu;Shin, Ho-Cheol;Lee, Eun-Ki
    • Nuclear Engineering and Technology
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    • v.39 no.6
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    • pp.725-730
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    • 2007
  • This paper describes recently developed techniques for effective filtering of neutron detector signal noise. In this paper, three kinds of noise filters are proposed and their performance is demonstrated for the estimation of reactivity. The tested filters are based on the unilateral kernel filter, unilateral kernel filter with adaptive bandwidth and bilateral filter to show their effectiveness in edge preservation. Filtering performance is compared with conventional low-pass and wavelet filters. The bilateral filter shows a remarkable improvement compared with unilateral kernel and wavelet filters. The effectiveness and simplicity of the unilateral kernel filter with adaptive bandwidth is also demonstrated by applying it to the reactivity measurement performed during reactor start-up physics tests.

Research of External Noise Influence by Preventive Analysis of Gas Insulated Switchgear and Its Shielding (가스절연개폐장치 예방진단시 외부 노이즈 영향과 차폐에 관한 연구)

  • Do, Yeong-Hoei;Kim, Jin-Hwan;Park, Han-Woo;Bak, Jong-Rae
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.313_314
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    • 2009
  • 현재 가스절연개폐장치 예방진단에 가장 광범위하게 적용되는 것이 UHF 부분방전 진단법이다. 부분방전시 방사되는 전자파 에너지를 Sensor가 수신하여 전압위상도에 신호강도를 표시하고 전자파 도달시간을 이용하여 결함위치를 쉽게 파악할 수 있는 장점이 있는 반면 Noise 간섭에 취약하여 부분방전 진단결과의 신뢰성이 확보되지 못하는 문제점이 있어 본 연구에서는 가스절연개폐장치의 부분방전 진단시 Noise의 영향과 차폐개선을 통한 부분방전 측정의 새로운 해법을 제시하고자 한다.

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APPLICATION OF SOUND INTENSITY METHOD TO NOISE CONTROL ENGINEERING AND BUILDING ACOUSTICS

  • Tachibana, Hideki
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1995.10a
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    • pp.7-15
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    • 1995
  • Sound pressure and particle velocity are the most essential quantities prescribing a sound field; they correspond to voltage and electric current respectively, in electric system. As electric power is the product of voltage and electric current, sound intensity is the product of sound pressure and particle velocity and it means the acoustic power passing through a unit area in a sound field. Although the definition of sound intensity is very simple as mentioned above, the method of measuring this quantity has not been realized for a long time, because it has been very difficult to measure the particle velocity simultaneously with the sound pressure. Owing to the recent development of such technologies as transducer production and digital signal processing, it has finally been realized. According to the sound intensity(SI) method, the sound power flow in an arbitrary sound field can be directly measured as a vector quantify. In this paper, the principle of the SI method is briefly explained at first and some examples of its application made in the author's laboratory are introduced.

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Noise Source Identification of Electric Parking Brake by Using Noise Contribution Analysis and Identifying Resonance of Vehicle System (차량 시스템의 소음 기여도분석 및 공진 규명을 통한 전자식 주차 브레이크 소음원 규명)

  • Park, Goon-Dong;Seo, Bum-June;Yang, In-Hyung;Jeong, Jae-Eun;Oh, Jae-Eung;Lee, Jung-Youn
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.3
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    • pp.119-125
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    • 2012
  • Caliper intergrated Electric Parking Brake (EPB) is an automatic parking brake system, attached to rear caliper. Because EPB uses luxury vehicles recently, the drivers of vehicles are sensitive to the EPB noise. EPB is operated by the motor and gear, so noise is generated by motor and gear. In order to reduce noise, One of EPB manufacturers uses helical gear and changes the shape of EPB housing. But these methods are not optimized for reduction of interior noise. There are many noise transfer paths into vehicle interior and it is difficult to identify the noise sources. Therefore, in this study, we performed contribution analysis and modal testing in the vehicle system. It is possible to distinguish between air-borne noise and structure-borne noise in the vehicle interior noise by comparing interior noise peak with resonance mode map.

Functional Analysis of Subsystem for Electric Plug Door (전기식 플러그 도어 하부시스템 기능 분석)

  • Joung, Eui-Jin;Hong, Jai-Sung;Won, Jong-Un;Lee, Jang-Mu;Lee, Han-Min;Kim, Gil-Dong
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.2198-2199
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    • 2011
  • The sliding door and plug door are the main types of door system in the EMU(Electric Multiple Unit). The sliding door is widely used in Korea but has weak point in the noise problem. In the low operation speed, the noise coming from outer side of the EMU is not an important factor. As the speed is higher than before, noise is increased and make an issue. The main cause of noise is the imperfect air tightness in the EMU. The plug door system has advantages for the noise reduction characteristic in the high speed area. Actually the noise level is an important factor for the passenger comfort. In this paper, we will describe the characteristic of electric plug door and functions of sub component.

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Optimization of the multi-chamber perforated muffler for the air processing unit of the fuel cell electric vehicle (연료전지 자동차용 흡기 소음기의 설계 변수 최적화에 관한 연구)

  • Kim, Eui-Youl;Kim, Min-Soo;Lee, Sang-Kwon;Seo, Sang-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.342-350
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    • 2009
  • Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

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The Design, Manufacture and Applications of a Gap Noise Generator for Testing the Characteristics of EMI from Transmission Lines (송전선로 EMI 특성 실험용 인공잡음발생장치 설계, 제작 및 적용)

  • Ju, Yun-Ro;Yang, Gwang-Ho;Myeong, Seong-Ho;Lee, Dong-Il;Sin, Gu-Yong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.1
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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.