• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.845-851
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• 2006

Folded lines are applied to design a compact microstrip ring hybrid. Using the proposed structure we achieve both significant size reduction and good harmonic suppression with the same results of conventional ring hybrid at 2.41 GHz. Including the third harmonic frequency, up to 11 GHz band harmonics are suppressed to -20 dB. The size of the proposed ring-hybrid is reduced to one forth of the conventional ring hybrid. The measured frequency responses agree well with simulated ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1137-1140
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• 2011

In this paper, the optimal condition for efficient active frequency multipliers is analyzed. This analysis is based on the effects from transistor nonlinear coefficients, harmonic impedances, and output parasitic components. From the analysis, normalized harmonic power is estimated with the clipping condition of a commercial transistor, and the condition for high conversion efficiency is suggested. From the analysis, a class-F frequency tripler was implemented for the output at 2.475 GHz, showing the maximum efficiency of 22.9 % and the maximum conversion gain of 9.5 dB.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.488-497
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• 2010

8100 series Electric locomotive was imported from SIEMENS of Germany on 2001. 8100 series model is modified from BR152 model to be complied with national environment. After 8100 series Electric locomotive carried out main line test for long time, 8200 series Electric locomotive produced in 10 locomotives with improvement and supplement on some parts. the one of supplement is to install the HEP equipment. In paper, about total harmonic distortion of HEP equipment power, it compares the result of combination with the result of actual measurement. It checks whether the measurement meets the specification of design or not. And it describes international standard about total harmonic distortion of supply system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.159-164
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• 2004

In this paper, we have proposed the folded feed structure for the spurious harmonic suppression and we have designed the SIR CPW bandpass filter using this feed structure. The characteristic of the proposed feed structure was similar to that of the lowpass filter has wide stopband region and this can be used usefully to the spurious harmonic suppression of the bandpass filter. From the simulation and the measurement result, SIR CPW bandpass filter with folded feed structure has good harmonic suppression characteristics up to 5.8 f$\sub$0/ with -20 dB suppression level.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.4
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• pp.13-18
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• 2009

This paper suggests that efficiency improvement of power amplifier to enhance harmonic suppression using a DGS line structure. A efficiency related harmonic component is an important factor to design of power amplifier. Therefor harmonic component suppress consisting coupled line using DGS after power amplifier. A DGS line with periodic slits and stubs is first designed and joined after power ampifier. Experimental measurements for efficiency of power amplifier in the WCDMA are shown to improve 6% of PAE.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.235-237
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• 2008

전기철도차량에서 사용하는 전력변환장치에 의해서 부하전류에 다양한 고조파가 포함되고 이러한 고조파는 전력품질에 영향을 미치게 된다. 틸팅열차는 현재 6량 1편성의 시제차량이 개발되어 호남선에서 시험을 실시하고 있다. 본 논문에서는 틸팅열차가 운행되는 동안 차량의 전력시스템을 평가하기 위해서 차량의 전압, 부하전류, 전력, 고조파를 측정한 결과에 대해서 서술하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2040-2041
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• 2008

본 논문은 최근 고도의 산업화 및 자동화, 전력전자 기술의 발전과 더불어 Power Electronics를 이용한 기술이 다양화됨에 따라 고조파 발생으로 인한 피해 방지 및 전력품질의 중요성이 대두되고 있는 가운데, 보다 효율적인 펌프운전을 위해 정밀성과 제어성능이 우수한 가변속 전력변환장치인 인버터가 적용된 최근 신설된 무인 수도사업장을 대상으로 저압 펌프모터의 기동특성과 고조파를 측정, 분석하여 국제기준에서 제시하는 고조파 관리기준에 적합성 여부를 분석한 사례를 중심으로 연구되었다.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.60-66
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• 2004

In order to analyze voltage, current electrical power, harmonic and so on of electrical load equipments, electrical power analysis by real measurement rather than mathematical modeling is necessary, and plan of countermeasure for efficient management, energy frugality and accident prevention of electrical equipments using it is possible Especially, electrical power analysis by real measurement is indispensable in order to consider countermove of harmonic occurred by nonlinear load So, in this paper, we developed DSP(Digital Signal Processor) based low price date aquisition system, and verified it's ability by performing measurement and analysis of electrical power and harmonic in the real power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.29-37
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• 2006

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonics produced by these devices are large, but also have noticeable time varying characteristics. Since the large loads are supplied from the power system grid, it must be recognized that not only will the system of utility be impacted, but neighboring customer system could be impacted as well. In this paper time-varying harmonics for high speed electric train loads are measured and evaluated by international harmonic standards IEEE Std. 519 and IEC 61000-3-6 using a cumulative probablistic approach.