• 전기학회논문지
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• 제62권10호
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• pp.1487-1493
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• 2013

A new simple control method for active power filter, which can realize the complete compensation of harmonics is proposed. In the proposed scheme, a model-based digital current control strategy is presented. The proposed control system is designed and implemented in a form referred to as internal model control structure. This method provides a convenient way for parameterizing the controller in term of the nominal system model, including time-delays. As a result, the resulting controller parameters are directly set based on the power circuit parameters, which make tuning of the controllers straightforward task. In the proposed control algorithm, overshoots and oscillations due to the computation time delay is prevented by explicit incorporating of the delay in the controller transfer function. In addition, a new compensating current reference generator employing resonance model implemented by a DSP(Digital Signal Processor) is introduced. Resonance model has an infinite gain at resonant frequency, and it exhibits a band-pass filter. Consequently, the difference between the instantaneous load current and the output of this model is the current reference signal for the harmonic compensation.

• Journal of Power Electronics
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• 제16권4호
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• pp.1288-1297
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• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

• 한국정보전자통신기술학회논문지
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• 제3권1호
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• pp.24-30
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• 2010

본 논문에서는 전기적 소형 모노폴 형태의 안테나가 제시되었다. 크기가 매우 짧은 (${\iota}{\approx}{\lambda}_g/15$ ) 모노폴은 용량성 소자로 동작하며, 접지면 위에 놓여진 개방형 슬롯구조는 유도성 소자로 동작하므로, 이 들 두 소자를 결합시킨 구조는 LC 공진기를 형성하게 된다. 안테나에 대한 등가회로 모델 은 안테나의 해석 및 설계의 정확성을 파악하기 위하여 사용되었다. 제안된 안테나는 매우 작은 전기적인 크기를 갖고 있으나 양호한 성능을 나타내고 있다. 측정된 안테나의 최대 이득과 효율은 주파수 2.1 GHz에서 각각 3.6 dBi 및 77.8 %를 나타내었다.

• 조명전기설비학회논문지
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• 제22권7호
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• pp.7-15
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• 2008

A single active capacitor snubber-assisted soft-switching sinewave pulse modulation utility-interactive power conditioner with a three-winding flyback high frequency transformer link and a bidirectional active power switch in its secondary side has been proposed. With the aid of the switched-capacitor quasi-resonant snubber cell, the high frequency switching devices in the primary side of the proposed DC-to-AC sinewave power inverter can be turned-off with ZVS commutation. In addition to this, the proposed power conditioner in the DCM can effectively take the advantages of ZCS turn-on commutation. Its output port is connected directly to the utility AC power source grid. At the end, the prototype of the proposed HF-UPC is built and tested in experiment. Its power conversion conditioning and processing circuit with a high frequency flyback transformer link is verified and the output sinewave current is qualified in accordance with the power quality guidelines of the utility AC interactive power systems.

• 전력전자학회논문지
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• 제10권5호
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• pp.518-525
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• 2005

제안된 회로는 하나의 보조스위치를 이용하여 주 스위치와 정류용 다이오드가 턴-온/턴-오프 시 동시에 영전압과 영전류 조건을 만족시킨다. 그리고 이 회로에 사용되는 주 스위치는 다수 캐리어 소자뿐만 아니라 소수 캐리어 반도체 소자까지 사용할 수 있는 장점을 가지고 모든 PWM 컨버터에 적용 가능하다. 그리고 제안된 보조 스위치와 공진회로가 주 전력 경로에 존재하지 않으므로 주 스위치와 다이오드에 더 이상의 전압/전류 스트레스가 없게 된다. 제안된 컨버터의 유효성을 이론적 분석과 실험을 통하여 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1163-1165
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• 1987

A novel temperature difference-to-frequency converter using two resistance temperature detectors (RTDs) has been developed. The resistance difference of two RTDs is converted into its equivalent inductance to form the resonant circuit of the Colpitts oscillator. The conversion sensitivity of $16\;Hz/^{\circ}C$ and the residual nonlinearity less than 2.15% over the temperature difference range from $35^{\circ}C$ to $155^{\circ}C$ are obtained by the prototype converter. The frequency drift of oscillator itself is ${\pm}0.5\;Hz$. Thus, the minimum detectable temperature difference is estimated to be ${\pm}0.013^{\circ}C$. The proposed converter, except for two RTDs, can be fabricated in monolithic IC form.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.93-95
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• 2005

Coupling capacitor voltage transformers (CCVT) are widely used in high voltage power systems to obtain standard low voltage signal for protective relaying and measuring instruments. To obtain high accuracy, capacitances and inductances are tuned to the power system frequency, making a parallel resonant circuit. When no fault occurs, no distortion of the secondary voltage is generated. However, when a fault occurs, harmonics generated break the resonance between capacitances and inductance, which generates the distortion of the secondary voltage. This paper proposes an algorithm for compensating the secondary voltage of the CCVT. With the values of the secondary voltage of the CCVT, the secondary currents, the primary currents and the voltages across the capacitors and inductor are calculated. Test results indicate that the proposed algorithm can compensate the distorted secondary voltage of the CCVT, and is irrespective of the fault distance, the fault inception angle and the burden.

• 대한전자공학회논문지
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• 제25권11호
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• pp.1282-1285
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• 1988

2개의 측온 저항체 온도 센서(RTD)를 이용한 온도차-주파수 변환기를 개발했다. 2개의 측온 저항체 온도 센서(RTD)의 저항차는 콜피츠 발진기의 공진 회로를 형성하는 등가 인덕턴스로 변환된다. 제안한 변환기는 35$^{\circ}C$에서 155$^{\circ}C$의 온도차 범위에서 16Hz/$^{\circ}C$의 변환 감도와 2.15%의 최대 직선 오차를 나타낸다. 발진기 자체의 주파수 드리프트는 $\pm$ 0.5Hz이다. 따라서, 최소 검출 가능 온도차는 $\pm$ 0,013$^{\circ}$C로 평가된다. 측온 저항체 온도 센서(RTD)을 제외한 모든 회로는 모노리딕 IC형태로 제작 할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1703-1705
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• 2001

The pulsed Nd:YAG laser is used widely for materials processing and medical instrument etc. It is important to control the laser energy in those fields using a pulsed Nd:YAG laser. In this paper, constant-frequency current resonant half-bridge inverter and Cockcroft-Walton circuit are used to charge the energy storage capacitor variably. This laser power supply is designed and fabricated which has no high-voltage transformer, less switching losses, compact size and capability in varying the laser output power. Also, the output characteristics of this Nd:YAG laser system are investigated. The tested results are described.

• 전기학회논문지
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• 제59권5호
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• pp.939-944
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• 2010

A high voltage air-cored helical strip/wire type pulse transformer has been fabricated for charging of a high voltage pulse forming line. As a primary coil, copper strip of 25mm width was wound helically around a MC nylon cylinder. For a secondary coil, copper enameled wire of 1mm diameter was wound around conical cylinder in order to provide insulation between two windings. The coupling coefficient of 0.53 was obtained when two coils were combined coaxially in the insulation oil filled chamber. Voltage gain and energy transfer efficiency were investigated by varying the parameters of primary and secondary circuit. Test results shows that the voltage gain increases up to 17 with increasing the primary capacitance up to 200nF. And highest energy transfer efficiency of 44% was obtained when the dual resonant operation condition was nearly satisfied. The pulse transformer developed in this study can be used for charging the middle conductor of a Blumlein pulse forming line.