• 전력전자학회논문지
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• 제18권2호
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• pp.131-137
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• 2013

In this paper, the phase-shift full-bridge DC/DC converter with fixed-phase operation inverter is proposed. The proposed circuit consists of two full-bridge inverters which are connected in parallel. While one full-bridge inverter operates as the fixed-phase, it regulates the output voltage by adjusting the phase of the other inverter. During the normal operation period, the proposed circuit makes the less amount of conduction loss of the primary switches and secondary synchronous rectifiers, as well as the less amount of the current ripple of the output inductor, than the conventional phase-shift full-bridge DC/DC converter does. Also, it achieves high efficiency by reducing the snubber loss of the secondary synchronous rectifier. To sum up, the present inquiry analyzes the theoretical characteristics of the proposed circuit, and shows the experimental results from a prototype for 450W power supply.

• 전기학회논문지P
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• 제63권4호
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• pp.361-367
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• 2014

This paper is related to a new solar power conditioner for a built-in step-up chopper function. In the first step-up chopper proposed solar PV power conditioner for mutually connected in series with the input voltage of the bypass diodes are respectively connected to the positive terminal should install the mutual boosting chopper diode connected in series with the boost chopper switching element between the two power supply and at the same time the first and the second was connected to a second diode and a resonance inductor and a snubber capacitor in series with each other. And the common connection point between the bypass diode and the step-up chopper and the step-up chopper diode common connection point of the switching elements of the input voltage was set to the boost inductor for storing energy. In addition, between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point of the first auxiliary diode and the second common connection point of the auxiliary diode was provided, the resonance capacitor. Between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point and the common connection point of the resonance inductor snubber capacitor and connecting the third secondary diode, between two power supply lines is characterized by configuring the DC link capacitor bus lines in parallel. Therefore, it is possible to suppress the switching loss through, DC link bus lines, as well as there could seek miniaturization and weight reduction of the power conditioner itself by using a common capacitor of the non-polar non-polar electrolytic capacitor having a capacitor, the service life of the circuit can be extended and it is possible to greatly reduce the loss can be greatly improve the reliability of the product and the operation of the product itself.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.299-301
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• 2006

계통연계형 태양광 시스템을 구성하고 있는 전력변환장치인 PCS(power conditioning system)는 일반적으로 그 내부에 입력전력 평활용 Capacitor, DC-DC Converter, DC link Capacitor, DC-AC Inverter 및 L-C Filter 등으로 구성된다. 이러한 태양광 시스템의 구성은 주로 태양광 어레이와 PCS의 DC-DC Converter 및 DC-AC Inverter의 수와 연결 방법에 따라 여러 가지로 구성할 수가 있다. 본 논문에서 제안할 시스템의 구성은 하나의 태양광 어레이를 다수의 계통연계형 태양광 PCS가 공유하는 형태인데, 이러한 시스템의 주요 장점은 첫째, 일사량에 따라 각각의 PCS가 모두 정격에서 운전하도록 하여 변환효율을 개선할 수 있다는 점과 둘째, 태양광 어레이의 용량 확장에 따른 PCS 장치의 용이한 확장성 그리고 셋째, 연결되어 있는 다수의 PCS 중 하나의 태양광 PCS가 고장으로 인하여 유지 및 보수가 필요할 때에도 그 외의 다른 정상적인 태양광 PCS는 지속적인 발전이 가능한 장점 등을 갖는다. 본 논문에서는 태양광 어레이의 출력을 공유하는 병렬운전용 태양광 PCS의 구성에 대하여 연구하고, 그 병렬운전기법을 제시하여 이에 대한 타당성을 시뮬레이션으로 검증하고자 한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권1호
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• pp.27-33
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• 1999

Compact fluorescent lamps are very sensitive to the variation of ambient temperature. This paper investigates the temperature characteristics of a 15[W] compact fluorescent lamp, and compensates the variation of light output by frequency control of its electronic ballast. Circuit parameters for the inverter of the electronic ballast are obtained by analyzing the R-L-C equivalent circuit for the inverter and the lamp. The optimum ratio of the two capacitance($C_1$/$C_2$), which are connected with the lamp in series and in parallel, respectively, is determined which consideration of the temperature variation within a range of 10~35[$^{\circ}C$]. As a result a value of 10 for the ratio is obtained at an operating frequency of 57[kHz], and with this value the frequency control works well for temperature compensation. Its validity is verified by investigating light output stabilization characteristics resulting from frequency control of the lamp at various temperatures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.230-231
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• 2007

계통연계형 태양광 시스템을 구성하고 있는 전력변환장치인 PCS(power conditioning system)는 일반적으로 그 내부에 입력전력 평활용 Capacitor, DC-DC Converter, DC link Capacitor, DC-AC Inverter 및 L-C Filter 등으로 구성된다. 이러한 태양광 시스템의 구성은 주로 태양광 어레이와 PCS의 DC-DC Converter 및 DC-AC Inverter의 수와 연결 방법에 따라 여러 가지로 구성할 수가 있다. 본 논문에서 제안할 시스템의 구성은 하나의 태양광 어레이를 다수의 계통 연계형 태양광 PCS가 공유하는 형태인데, 이러한 시스템의 주요 장점은 첫째, 일사량에 따라 각각의 PCS가 모두 정격에서 운전하도록 하여 변환효율을 개선할 수 있다는 점과 둘째, 태양광 어레이의 용량 확장에 따른 PCS 장치의 용이한 확장성 그리고 셋째, 연결되어 있는 다수의 PCS 중 하나의 태양광 PCS가 고장으로 인하여 유지 및 보수가 필요할 때에도 그 외의 다른 정상적인 태양광 PCS는 지속적인 발전이 가능한 장점 등을 갖는다. 본 논문에서는 태양광 어레이의 출력을 공유하는 병렬운전용 태양광 PCS의 구성에 대하여 연구하고, 그 병렬운전기법을 제시하여 이에 대한 타당성을 시뮬레이션으로 검증하고자 한다.

• 전력전자학회논문지
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• 제20권3호
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• pp.223-231
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• 2015

LEDs have been widely used in lighting displays, automobiles, and airplanes owing to their excellent light output characteristics and long lifespan. Though LEDs are manufactured under the same process, variations in impurity concentrations cause electrical deviation among LEDs. The resulting electrical deviation can not only reduce the life time of the LED but also cause non-uniform luminance of LEDs connected in parallel. LED driving circuit is required to solve these problems. In this paper, we propose a LED driving system using Y-type current balancing transformer to maximize the efficiency of the system by removing output stage Schottky diodes. Experimental results are presented to verify the performance of proposed LED driving system that is applied to 80 W LED modules.

• 전력전자학회논문지
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• 제5권6호
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• pp.544-551
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• 2000

In this paper, 3-phase hybrid series active power filter for compensate current harmonics, voltage drop and unbalanced voltage in the network presented. The proposed system is implemented with a space vector modulation voltage source inverter and a high pass filter connected in parallel to the power system. Here the load is six-pulses thyristor rectifier. The phase angle detected in order to generation reference voltage at load terminal is synchronized with the positive sequence component of the unbalanced source by using symmetrical component transformation. The proposed system has an function harmonic isolation between source and load, voltage regulation, and unbalance compensation. Therefore, what the power system is improved quality, the source current is maintained as a nearly sinusoidal waveform and the load voltage is regulated with a rated voltage regardless of the source variation condition. To verify the validity of the proposed compensating system, the computer simulation and experiment are carried out.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2033-2035
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• 1998

This paper describes a DC-DC converter connected two unites inverters, a half-bridge type of high frequency resonance inverter, at the input with parallel. The proposed paper certified that theorem waveforms are equal to experiment waveforms, in addition, it estimated characteristics such as characteristic of average power, characteristic of average output voltage, characterisic of output voltage ripple etc., for designing the device with normalized parameter value.

• 전력전자학회논문지
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• 제21권6호
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• pp.525-529
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• 2016

In the case of a motor system that converts electrical energy into mechanical energy, the region of the motor and that of the generator coexists. In the case of an escalator, the ascending escalator is operated by the motor, whereas the descending escalator is operated by the generator according to the load. To evaluate the proposed method, this study reduces the power of the ascending escalator up to approximately 35% by sharing the regeneration power of the descending escalator. The loss of transfer power nearly exists in the case of the proposed method. Furthermore, the lifetime of the DC link condenser can be extended because it is connected in parallel, thus leading to a twofold increase in capacity.

• 한국전자통신학회논문지
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• 제7권1호
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• pp.81-89
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• 2012

범용적으로 사용되고 있는 수평형 풍력 터빈(HAWT)은 블레이드가 장착된 터빈이 회전부인 너셀에 고정되어 타워의 최상단에 지지되는 구조이다. 터빈에서 생산되는 전력은 너셀 내부에서 증속기를 통하여 발전기로 들어가게 된다. 발전기에서 생산되는 전력은 타워를 통해서 지상과 송전선으로 연결되므로 너셀의 요잉이 발생하는 경우 송전선의 꼬임이 발생하게 된다. 따라서 이를 방지하기 위한 슬립링이나 추가적인 요잉 제어 알고리즘이 필요한 단점이 있다. 제안하는 새로운 구조의 HAWT는 베벨기어와 중공축을 이용하여 송전선 문제를 해결하였다. 또한, 병렬로 접속된 두개의 발전기를 이용하여 요잉이 용이할 뿐 아니라 생산 전력을 분산시킴으로써 인버터의 용량을 줄일 수 있다. MPPT 알고리즘과 요잉 제어를 수행하는 시뮬레이션을 통해서 제안하는 구조가 풍력 발전에 효과적임을 보였다.