• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.836-842
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• 2005

This paper presents a power supply of railway signal system using a Z-source inverter. The Z-source inverter overcomes the conceptual and theoretical barriers and limitations of the tradition voltage-source inverter and current-source inverter and provides novel power conversion concept. The Z-source inverter is a Buck-Boost inverter that has a wide range of obtainable voltage.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.291-297
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• 2003

This paper presents a current-source-inverter based on a buck-boost configuration and its application for residential photovoltaic system. The proposed circuit has five switches. Among them, only one switch acts as chopping, and the other determine the polarity of output; therefore, it can reduce the switching loss. Because the input inductor current is operated on the discontinuous conduction mode, high power factor can be achieved without additional input current controller. So the overall system shows a simple structure. The operational modes are analysed in depth, and then it was verified through the experimental results using a 150 [W] prototype equipped with digital signal processor TMS320F241.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.57-61
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• 2002

This paper presents a current-source-inverter based on a buck-boost configuration and its application for residential photovoltaic system. The proposed circuit has five switches. Among them, only one switch acts as chopping, and the other determine the polarity of output; therefore, it can reduce the switching loss. Because the input inductor current is operated on the discontinuous conduction mode, high power factor can be achieved without additional input current controller. So the overall system shows a simple structure. The operational modes are analysed in depth, and then it was verified through the experimental results using a 150 W prototype.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.67-75
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• 2011

The development of electric vehicle power electronics system control, composed of DC-AC inverters and DC-DC converters, attract much research interest in the modern industry. A DC-AC inverter supplies the high-power motor torques of the propulsion system and utility loads of electric vehicles, whereas a DC-DC converter supplies the conventional low-power and low-voltage loads. However, the need for high-power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. The nonlinear control of power converters is an active research area in the field of power electronics. This paper focuses on the use of the fuzzy sliding mode strategy as a control strategy for buck-boost DC-DC converter power supplies in electric vehicles. The proposed fuzzy controller specifies changes in control signals based on the surface and knowledge on surface changes to satisfy the sliding mode stability and attraction conditions. The performance of the proposed fuzzy sliding controller is compared to that of the classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law, which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variations in load resistance and input voltage in the studied converter.

• 전력전자학회논문지
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• 제18권4호
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• pp.305-311
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• 2013

This paper proposes a performance improvement of existing single-phase current-fed qZ-Source inverter. Voltage gain of the traditional voltage-fed full-bridge inverter and single-phase current-fed qZ-source inverter is only equal to or smaller than input voltage. The proposed inverter can obtain twice higher voltage gain than the single-phase current-fed qZ-Source inverter by adding an extra switch and a capacitor in the circuit. In addition, the proposed inverter shares the common ground between dc input and ac output voltage. Therefore, the proposed inverter can eliminate the possible ground leakage current problem when it is used for grid-tied photovoltaic inverter system. A 120 W prototype inverter is built and tested to verify performances of the proposed inverter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.387-389
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• 2006

The LCD TV has many variable functions for consumer. Low temperature driving below minus 20 degree is also one of key functions. Since LCD is not self-luminance device, it is needed backlight system. Recently EEFL(External Electrode Fluorescent Lamp) widely substitutes for CCFL(Cold Cathode Fluorescent Lamp). It is more cheaper, higher efficiency, and easy to drive parallel connection compared to CCFL. In this paper, several conditions for low temperature driving of EEFL are investigated and a new boost-half bridge inverter for low temperature driving is proposed. Mode analysis is described and experimental results is represented to verify validity of the proposed inverter.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1274-1281
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• 2016

• 전력전자학회논문지
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• 제7권5호
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• pp.437-442
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• 2002

본 논문에서는 벅-부스트 형태에 기초한 전류형 PWM 인버터를 제안하고, 이를 태양광과 계통 연계를 위한 인터페이스 회로로서의 타당성을 검증하였다. 제안하는 회로는 다섯 개의 스위칭 소자를 가지게 되는데, 이 중 단 하나의 스위치만이 쵸핑 동작을 수행하게 되고, 나머지 스위치들은 출력단의 정·부 방향을 결정짓는데 이용된다. 따라서, 스위칭에 의한 손실을 상당히 저감시킬 수 있고, 입력단의 인덕터 전류를 전류 불연속 모드로 동작시켜 별도의 입력 전류의 검출이 없이도 출력단을 단위 역률화 할 수 있는 장점을 가진다. 제안하는 계통 연계형 인버터에 대한 동작을 이론적으로 분석하고 DSP TMS320F241을 이용한 150[W]급 시작품의 실험 결과로부터 제안하는 인버터의 타당성을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권11호
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• pp.635-644
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• 2002

Many generating units can be in parallel connection to one battery and inverter. However, one of the biggest problems we encountered is that wind speed is fluctuated sharply in accordance with the unstable weather conditions. To solve this problem, we need energy storage equipment such as storage lead-acid battery. We design a system and analyze its modeling so that it supplies a stable power to the load through DC-AC inverter part. In this paper, we applied dual step-up/down buck-boost converter and dual high-frequency half-bridge converter to the proposed system. These converters are used to store energy in the battery regardless of the change of the wind speed. The operation process of two proposed types of converters for high-power battery charging is discussed along with simulation and experimental result. We design a charging circuit which is applicable in the actual wind power generation system for 30kw and confirm the circuit's validity.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.453-454
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• 2011

본 논문에서는 벅-부스트와 포워드 컨버터의 기능을 갖는 컨버터를 제안한다. 제안하는 컨버터는 Cascaded H-bridge 멀티레벨인버터와 같이 다수의 독립된 전원을 요구하는 회로 구조를 단일 입력 전원단으로 구성할 수 있는 특징을 가진다. 벅-부스트 컨버터의 입력 인덕터는 변압기로 대체되며 컨버터 스위치의 ON 동작시 포워드 동작에 의해 변압기 2차측으로 전력전달이 이루어지며, 스위치 OFF시 변압기 1차측 자화인덕턴스에 저장된 에너지가 비절연된 벅-부스트 컨버터의 출력 커패시터로 전달된다. 제안된 컨버터의 동작 모드에 따른 이론적 분석을 시행하고 시뮬레이션을 통해 타당성을 검증한다.