• 한국산학기술학회논문지
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• 제17권4호
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• pp.26-33
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• 2016

최근 UPS의 효율을 높이기 위하여 무변압기형 UPS의 사용이 증가되고 있다. 하지만 무변압기형 UPS는 입 출력 구조상 문제로 인해 3상4선식의 IGBT PWM 정류기가 필요하며 이는 기존의 3상3선식 PWM 정류기의 PFC 제어기법으로는 중성선 전류 문제로 동작이 되지 않으므로 3상4선식 PWM 정류기의 특성에 맞는 적절한 PWM 제어기법이 요구되고 있다. 3상4선식 IGBT PWM 정류기의 제어를 위한 제어기법으로는 각상 개별제어 기법과 3D SVM 기법이 있지만 두 방식 모두 장단점이 존재한다. 각상 개별제어 기법은 제어가 불안정하고 3D SVM 기법은 입력 측 인덕터의 L값이 상당히 커져야하는 문제점을 가지고 있다. 따라서 본 논문에서는 기존의 각상 개별제어 방식과 d-q 제어 알고리즘을 접목시켜 동기좌표계상에서 직류로 제어하는 3상4선식 IGBT PWM 정류기 제어기법을 제안하였다. 또한 본 논문에서 제안한 3상4선식 IGBT의 PWM 정류기 제어 알고리즘을 바탕으로 시뮬레이션과 실험을 수행 하였다. 시뮬레이션을 수행한 결과, 3상4선식 IGBT PWM 정류기를 안정적으로 제어하고 중성선 전류를 줄일 수 있어, 본 논문에서 제안한 방식의 유효성을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.267-269
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• 2006

In this paper, a new single phase voltage sag/swell compensator using direct power conversion is introduced. A new compensator consists of input/output filter, series transformer and direct ac-ac converter, which is a single-phase back-to-back PWM converter without dc-link capacitors. Advantages of the proposed compensator include: simple power circuit by eliminating dc-link electrolytic capacitors and thereby, improved reliability and increased life time of the entire compensator; simple PWM strategy to compensate voltage sag/swell at the same time and reduced switching losses in the ac-ac converter. Further, the proposed scheme is able to adopt simple switch commutation method without requiring complex four-step commutation method commonly required in the direct power conversion. Simulation results are shown to demonstrate the advantages of the new compensator and PWM strategy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.166-170
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• 1997

A Single phase induction motor is the predominant fractional horsepower power rated, extensively used in domestic and industrial application. For example, these motors provide the motive power to washing machines, fans, refrigerators, etc. In this paper, single phase induction motor input current was detected by a small current transformer and determined TRIAC gate signal by using op-amp analog circuit. The soft-start strategy is based on limited auxiliary current angle during starting period in the closed-loop control. The Simulation and experimental result show the motor's starting characteristics of the proposal starting system and are compared with centrifugal switch starting motor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.352-357
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• 2003

A new single stage power factor correction(PFC) AC/DC converter based on zero voltage switching(ZVS) full bridge topology is proposed. Since the series-connected two transformers act as both output inductor and main transformer by turns, the proposed converter has a wide ZVS range without additional devices for ZVS. Furthermore, since there is no need to use an output inductor, the proposed converter features high power density. The proposed converter gives the good power factor correction and low line current harmonics distortion. A mode analysis and experiment results are presented to verify the validity of the proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.66-68
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• 2003

This paper proposes the single stage boost input type resonant AC-DC converter. Proposed converter uses the resonance between leakage inductance of the transformer and resonance capacitance. And it obtains high power factor more than 98$\%$ through continuous current mode pulse width modulation. To verify the validity of the proposed converter, operation principle In the steady state is analyzed and experimental results are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.415-418
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• 1994

In this paper, a parallel operation of two single-phase GTO PWM converters is presented. The current ripples on the primary side of the transformer can be much reduced by shifting one modulation period from the other one by a half period. Also, a simple power factor control scheme is presented by which the reactive component of converter input current is controlled. Simulations and experimental results for a laboratory system confirm the validity of the purposed algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.670-673
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• 2000

This paper describes a new inverter active inverter between a photovoltaic(PV) array and single-phase utility that avoid the bulky input(60Hz) transformer on the AC side. The interface employs a pwm boost converter on the DC side followed by a pwm boost converter on the DC side followed by a pwm current-forced single-phase rectifier for injecting the power from the PV array into the mains. The current waveform at the AC side remains sinusoidal and exactly in phase at all time. The circuit also has the advantage of requiring fewer switching device than high-frequency link system. This paper describes modeling of PV array and new system topology. Simulation results on the performance of the connection are also presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.145-146
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• 2011

In this paper, a bridgeless flyback power factor correction (PFC) rectifier which uses single magnetic core is proposed. The proposed PFC rectifiers utilize bidirectional switch to handle both positive and negative input voltage without bridge diodes. A transformer with dual output windings enables the rectifier dispense with any additional magnetic component. The operation of the proposed flyback PFC rectifier is analyzed, and its higher efficiency than its conventional counterpart is verified by experiment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.319-322
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• 1999

This paper presents a novel single-stage Power Factor Corrected(PFC) AC/DC forward converter with semi-automatic current shaping in order to achieve the unity power factor and an isolated output. Since the proposed circuit is combined a boost converter used for PFCs with a forward converter used for DC to DC conversion, the over-all size of system could be reduced. And thanks to the zero voltage switching(ZVS) in both switches, the voltage stress can be reduced considerably. A simple auxiliary circuit adopted into the secondary of transformer is composed of lossless components for reducing surge voltage. A prototype which has tow IGBT(Insulated Gate Bypolar Transistor) modules as switching device is manufactured to evaluate the proposed topology. The characteristics of the proposed circuit are tested, and the validity is verified by experimental results.