• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1999-2001
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• 1997

The main two drawbacks of the Sin91e Stage PFC (SS-PFC) converters employing a DCM Boost PFC cell are relatively high voltage stress on the bulk capacitor and the input current harmonic distortion. The high voltage stress on bulk capacitor makes the SS-PFC converter impractical in a universal input application and the input current harmonic distortion lowers power factor. In this paper a selective variable frequency control that reduces the voltage stress on the bulk capacitor and the input current harmonic distortion is proposed. Computer simulation results of the proposed control method are presented.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.151-154
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• 2010

본 논문에서는 분산전원 연계선로의 분산전원 과도특성과 전력품질을 분석하기 위해 AC전원 모의 장치를 이용하여 저압 배전계통 측에서 순간전압강하(Voltage Sag), 순간전압상승(Voltage swell), 고조파(THD) 주입 등의 배전계통에 일어날 수 있는 비정상 상태를 발생시켜, 분산전원의 과도특성을 분석하여, 그 결과가 분산전원 계통연계 기술기준[9]-[11]에서 정한 규정치에 적합한가에 대한 기술적인 검토사항을 분석하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.121-127
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• 2004

Electric ballast is widely used to turn on the fluorescent. Electric ballast measure occurrence of harmonic through the actual measurement and it is simulated by modeling equivalent circuit for harmonic analysis. The purpose of this paper is to give an equivalent circuit modeling methodology for the harmonic currents generated by single-phase personal computer loads to evaluate a commercially available series resonant filter for the harmonic currents compensation based on the IEC std 61000-3-2 and IEEE 519 standards for limiting harmonic distortion.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2077-2078
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• 2011

Now a days, the induction motor is widely used in industry automation. Without monitoring the motor fault, maintenance cost is increased undesirably high. The slip frequency is included in the feature frequency, so rotating rotor speed is needed. In this paper, a sensorless motor speed estimation method, rotor slot harmonic(RSH) method is suggested and a solution of rotor bar diagnosis is proposed for motor running with light-load. When the rotor is rotating, it shows the harmonic signal of back-emf voltage related with number of rotor slot. So from the power spectrum of current signal, we can find the rotor speed.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.681-683
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• 2011

최근 태양광 및 풍력과 같은 신재생에너지원을 기반으로 한 국가정책에 따라 대규모의 분산전원이 도입 운용되고 있다. 그러나 대용량 분산전원의 계통연계에 대한 기술기준 및 체계적인 선로운영 기술기준이 미흡한 상태이며 정상상태 운용에서 태양광이 배전계통에 연계시 수용가 말단에 전력품질과 고조파 문제가 발생하여 분산전원의 배전계통 전압변동 특성 해석이 필요하다. 이에 본 논문에서는 태양광 전원이 배전계통에 연계 운전시 발생되는 문제를 분석하기 위해 배전계통의 대표적인 상용소프트웨어인 PSCAD/EMTDC를 이용하여 모델링을 수행하였다. 그리고 Simulation결과와 이론적인 수식과 비교, 분석을 통해 PV의 계통연계 전압특성을 제시하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.2
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• pp.41-48
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• 1997

Nowadays, EMI emission characteristics, which causes harmful effect on power distribution system and other equipments, have been studied in field of Power electronics, vigoriously. So, in this paper, the conducted EMI emission is measured and compared for 3-phase diode rectifier and PWM converter according to switching frequency variation and current control method change using LISN(Line Impedance Stabilization Network) and spectrum analyzer.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.787-790
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• 2004

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics and power factor correction in unified active power filter systems combined with shunt passive filters is proposed, where no low/high-pass filter are used in deriving the reference voltage for compensation. Using digital all-pass filters, the phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage. The amplitude of d-axis current in a series filter is controlled as zero for power factor correction. The validity of the proposed control scheme has been verified by experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.199-210
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• 2003

In this paper, the new Islanding detection method is studied for utility interactive photovoltaic system(UIPVS). It describes the brief of UIPV system and the features of islanding phenomenon. The new islanding detection method for improving the detection characteristics, HCIM(Harmonic Current Injection Method), is proposed and analyzed. The impedance curve of AC load is derived from the complex power equation for testing Islanding detection features. The proposed detection method and the derivation of islanding condition we verified by the simulation with ACSL and the laboratorial experiments.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.157-158
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• 2014

단상 계통연계형 인버터에서 전류센서를 통한 상전류 측정시 옵셋 오차는 전류센서와 측정 경로상에 위치한 아날로그 소자의 전압 불균형 및 비선형성으로 인하여 발생하게 된다. 또한 데드타임은 전력용 반도체 스위치를 제어하기 위한 PWM 신호 출력시 필연적으로 발생된다. 본 논문에서는 데드타임으로 인하여 왜곡된 상전류에 포함된 옵셋 오차에 의한 영향을 분석하고 동기좌표계 dq축 전류에 포함된 특정 고조파 성분을 제거하기 위하여 PR 제어기를 사용한 알고리즘이 제안되었다. 데드타임 및 옵셋 오차로 인해 발생된 전류맥동 보상을 위한 기준신호로는 동기좌표계 dq축 전류를 사용하였다. 제안된 알고리즘의 타당성을 시뮬레이션과 실험을 통하여 증명하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.338-341
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• 1999

PWM controlled line-side converters of modern ac traction locomotives inject harmonic currents into the feeding overhead line. This causes problem of electromagnetic interference. Passive and Active filters are usually provided for a reduction of the line harmonics. Active filters are more reasonable than passive filters in terms of weight and space of the filters. Successful control of active filters requires an accurate harmonic current reference. A technique to generate the harmonic current reference is proposed in this paper. The analysis is performed in frequency domain and its effectiveness is verified by simulation.