• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.136-136
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• 2009

It is investigated the cut-off frequency of Z-cut quartz microstrip low pass filter by the variation of applied electric field. Designed microstrip filter was simulated using the Ensemble v7.0(Ansoft). As a result of the experiment, the cut-off frequency showed 50 MHz shift when the applied electric field was 3 kV/cm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.955-960
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• 1998

Electrified railroads inject large amount of harmonics, negative sequence and reactive currents to electric supply systems. This paper introduces application of active filter as a 3/1 phase converter for electrified railroad. In this system active filter compensate harmonics, negative sequence and reactive currents and electric railroad and active filter together act as a balance three-phase load with power factor 1

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.153-160
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• 2006

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for dc voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

• 한국철도학회논문집
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• 제13권6호
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• pp.559-564
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• 2010

본 논문은 동력 집중식 철도차량에서 전력변환장치로서 객차용 전원공급장치의 전력품질을 향상시키기 위해 보완된 필터설계를 제안한다. 먼저, 필터설계를 위해 객차용 전원공급장치와 연결된 변압기의 출력전력 파형을 측정하였다. 실험 및 시뮬레이션 결과를 통해 스위칭 기법은 개선된 특정고조파 소거 펄스폭 변조이고 스위칭 주파수는 300Hz임을 추정하였다. 따라서 추정된 파라미터를 바탕으로 전력품질을 향상시키기 위해 필터를 설계하였다. 시뮬레이션 결과 전체적으로 고조파의 크기가 감소함을 확인하였다.

• Journal of Power Electronics
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• 제19권6호
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• pp.1380-1392
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• 2019

Input filters are very important to matrix converters (MCs). They are used to improve grid side current waveform quality and to reduce the input voltage distortion supplied to the grid side. Due to the effects of the input filter and the output power, the grid side power factor (PF) is not at unity when the input power factor angle is zero. In this paper, the displacement angle between the grid side phase current and the phase voltage affected by the input filter parameters and output power is analyzed. Based on this, a new grid side PF unity compensation method implemented in the indirect space vector pulse width modulation (ISVPWM) method is presented, which has a larger compensation angle than the traditional compensation method, showing a higher grid side PF at unity in a wide output power range. Simulation and experimental results verify that the analysis of the displacement angle between the grid side phase current and the phase voltage affected by the input filter and output power is right and that the proposed compensation method has a better grid side PF at unity.

• 전력전자학회논문지
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• 제22권5호
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• pp.382-389
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• 2017

The development of electronic technology has been rapidly achieved in the automotive industry. A trend that attaches electric equipment, including ECUs at vehicles, is observed. However, decrepit vehicles have several electrical noises and errors. The effect of electric noise on vehicles that are focused on smoke was investigated. Many researchers have argued that one of the reasons of the occurrence of smoke in vehicles is the inexact time of the occurrence of ignition. Moreover, various physical, chemical, and thermodynamic solutions were attempted to approach and many improvements were accomplished. However, in this study, the reduction of electrical and electronic noise is confirmed to improve the accuracy of the injection time on decrepit vehicles with electrical and electric technologies. Previous studies suggest that the distance between the pilot and main ignitions affect the occurrence of smoke and control the variance value of the distance between pilot and main ignitions with electric filter. Thus, the effect of reducing smoke occurred.

• 한국공작기계학회논문집
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• 제10권1호
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• pp.10-15
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• 2001

Urgent increasing of the vehicles influence air pollution and the damage of the plants and animals. Particularly, exhaust-ing particulate of diesel vehicles give serious effect to human life. Therefore, this study aim to reduce amount of particulate and to contribute developing after-treatment in diesel engine. Through the experimental and theoretical study about charac-teristics of the electric heat regeneration, various results are obtained.

• 전기학회논문지
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• 제66권1호
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• pp.211-215
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• 2017

The APF (All Pass Filter) method that utilizes the computational power of the controller is most commonly used. However, since the calculation of the filter coefficient is complicated, the calculation is carried out in advance. It is difficult to apply it to the frequency fluctuation environment because the coefficient value is fixed. In this paper, a new control method of single phase PLL that can be usefully used in PWM converter device for electric railway was explained. Comparison and examination of similarities and differences between the conventional APF method PLL controller method and the newly proposed modified MA filter method PLL technique were performed. The possibility of implementation of the modified MA filter method through computer simulation was analyzed. In conclusion, the method proposed as the conclusion was applied to the APU(Auxiliary Power System) of 8200 Series Electric Locomotive and its usefulness was confirmed.

• 제어로봇시스템학회논문지
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• 제7권8호
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• pp.703-710
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• 2001

The nonlinear observers are proposed for a nonlinear system. To improve the characteristics such as stability, convergence, and $H^{\infty}$ filter performance criterion, we utilize an $H^{\infty}$ filter Riccati equation or a modified $H^{\infty}$ filter Riccati equation with a freedom parameter. Using the Lyapunov function method, the characteristics of the observers are analyzed. Then the in-flight alignment for a strapdown inertial navigation system(SDINS) is designed using the proposed observer. And the additive quaternion error model is especially used to reduce the uncertainty of the SDINS error model. Simulation results show that the observer with the modified $H^{\infty}$ filter Riccati equation effectively improves the performance of the in-flight alignment.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권6호
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• pp.300-305
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• 2004

In this paper, new design equations based on the pole-zero analysis for multi-layered interdigital stripline linear group delay bandpass filter with tap input ports are presented. As a design example, a four-pole group delay filter with center frequency of 2.14GHz, bandwidth of 160MHz, and group delay variation of $\pm$0.1nS for LTCC technology or multilayered PCB technology is designed. In the design process, it is not necessary to simulate the entire structure, as the simulation of half structures is sufficient. Good results can be attained after the optimizing process was performed three times using the proposed equations and a commercial EM simulator.