• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.373-374
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• 2017

최근 개발 및 출시되고 있는 전기자동차(EV) 충전시스템은 3상 AC전원을 입력받아 입력역률개선과 고효율 AC/DC변환을 위한 Interleaved PFC컨버터, Bridgeless PFC컨버터, 3-Level 비엔나정류기(VIENNEA Rectifier) 등의 Topology가 사용되고 있으며, 변환된 DC전압을 입력받아 배터리를 충전하기 위한 절연된 고주파 DC/DC컨버터로 LLC 공진컨버터, 3레벨 컨버터 등이 사용되어 사이즈저감 및 경량화를 꾀하고 있다. 본 논문은 기존 입력역률 개선을 위한 PFC 컨버터와 배터리 충전을 위한 절연형 DC/DC 컨버터 2단으로 구성되어진 충전시스템 대신에 사이즈저감 및 효율개선 그리고 넓은 범위의 출력전압제어(200Vdc~430Vdc)에 대응 할 수 있도록 '단일전력단 3레벨 하이브리드 AC/DC 컨버터'를 제안하였고, 2kW 시제품을 제작하여 실험을 통해 적용 가능성을 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.137-139
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• 1993

This paper details methods used to verify the adquacy of a dc traction power supply for design in Seoul matropolitain subway Line-6 system. Examples of the approach are given for a major subway presently under construction. The performance of trains operating at maximum system design capacity is modelled using a train simulation program. Using a dc network analyser program, the maximum train operating timetable, and a model of the ac and dc electrical suppy system, the electrical performance of the entire system can be modelled over a 24-hour period. The results of this analysis are used to determime: train voltage at a level sufficient to ensure train schedules: adequacy of traction transformers, rectifier, and switchgear ratings; sizes of the overhead contact systern conductors, and ac and de feeder cables: and power and energy demands at the utility company's supply points for inital and final timetable operations.

• Journal of Power Electronics
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• 제17권1호
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• pp.212-221
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• 2017

Permanent-Magnet Synchronous Generators (PMSGs) are used widely in Wind Power Generation Systems (WPGSs), and the Vienna rectifier was recently proposed to be used as the generator-side converter to rectify the AC output voltage in PMSG-based WPGS. Compared to conventional six-switch two-level PWM (2L-PWM) converters, the Vienna rectifier has several advantages, such as higher efficiency, improved total harmonic distortion, etc. The motivation behind this paper is to verify the performance of direct-driven PMSG wind turbine system based-Vienna rectifier by using a simulated direct-driven PMSG WPGS. In addition, for the purpose of reducing the reactive power loss of PMSGs, this paper proposes an induced voltage sensing scheme which can make the stator current maintain accurate synchronization with the induced voltage. Meanwhile, considering the Neutral-Point Voltage (NPV) variation in the DC-side of the Vienna rectifier, a NPV balancing control strategy is added to the control system. In addition, both the effectiveness of the proposed method and the performance of the direct-driven PMSG based-Vienna rectifier are verified by simulation and experimental results.

• 조명전기설비학회논문지
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• 제19권6호
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• pp.16-21
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• 2005

본 논문에서는 고주파 트랜스의 여자 전류를 이용하지 않고, 인덕턴스를 이용한 새로운 부분공진 영전압 스위칭 PWM제어 고주파 절연형 풀-브리지 DC/DC 컨버터의 회로를 제안하여 그 동작 원리를 기존 방식과 특성을 비교하였다. 또한 고주파 절연 트랜스 2차측에 동기 정류용 전력용 MOSFET에 새로운 기능을 부가한 온-오프 제어방식을 이용하여 넓은 부하 범위에 걸쳐 안정된 영전압 스위칭(ZVS)동작을 실현하였다. 또한 제안한 DC-DC 컨버터의 실험장치에 의해서 실측 효율을 97[%]이상 달성하였고 직류 무정전전원의 PWM 정류기의 출력단에 이용되는 새로운 방식이 스위칭 전원으로서 유효성을 증명하였다.

• Journal of Power Electronics
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• 제16권2호
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• pp.464-472
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• 2016

This study applies the selective harmonic elimination (SHE) technique to design and operate a regulated AC/DC/AC power supply suitable for maritime military applications and underground trains. The input is a single 50/60 Hz AC voltage, and the output is a 400 Hz regulated voltage. The switching angles for a multi-level inverter and transformer turns ratio are determined to operate with special connected transformers with equal power ratings and produce an almost sinusoidal current. As a result of its capability of directly controlling harmonics, the SHE technique is applicable to apparatus with congenital immunity to specific harmonics, such as series-connected transformers, which are specially designed to equally share the total load power. In the present work, a single-phase 50/60 Hz input source is rectified via a semi-controlled bridge rectifier to control DC voltage levels and thereby regulate the output load voltage at a constant level. The DC-rectified voltage then supplies six single-phase quazi-square H-bridge inverters, each of which supplies the primary of a single-phase transformer. The secondaries of the six transformers are connected in series. Through off-line calculation, the switching angles of the six inverters and the turns ratios of the six transformers are designed to ensure equal power distribution for the transformers. The SHE technique is also employed to eliminate the higher-order harmonics of the output voltage. A digital implementation is carried out to determine the switching angles. Theoretical results are demonstrated, and a scaled-down experimental 600 VA prototype is built to verify the validity of the proposed system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.984-985
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• 2008

In this paper, MPPT(maximum power point tracking) control method of the seaflow generation system using DC-DC converters is proposed. This system consists of a variable speed seaflow generation system with permanent magnet synchronous generator, diode rectifier and DC-DC converter. In this proposed seaflow generation system, diode rectifier and DC-DC converter use for converting AC to DC and maximum power generation control, respectively. Advantages of MPPT control method presented in this paper don’t need to use the characteristic of the seaflow turbine at various seaflow speed and measure the seaflow speed and the rotating speed of seaflow turbine. Therefore, the proposed system has the characteristics of lower cost, lower complexity and higher efficiency. The effectiveness of algorithm is simulated and confirmed through Matlab Simulink.

• 조명전기설비학회논문지
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• 제23권8호
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• pp.48-56
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• 2009

본 논문은 연료전지스택을 입력전원으로 하는 TIG-용접기용 전력변환장치를 제안하였다. 일반적으로 TIG-용접기의 전원공급장치는 상용전원을 이용한 다이오드 브리지 정류회로를 사용한다. 이런 회로의 경우 다이오드 정류기와 용량이 큰 캐패시터를 사용하게 되므로 부피가 커지고, 입력전류는 맥동성분과 고조파를 포함하게 된다. 또한, TIG-용접기는 상용전원의 사용이 여의치 않은 도서산간지역이나 특수한 환경에서는 소형 경량의 이동성이 수월한 전원장치 및 전력원을 필요로 하게 된다. 따라서 본 논문의 TIG-용접기용 전력변환장치는 고체고분자형연료전지(PEMFC)를 입력전원으로 사용하고, 부스트 컨버터의 기능과 인버터 용접전원의 기능을 하나의 풀-브리지 컨버터로 구성하였다. 제안한 연료전지를 이용한 TIG-용접기용 전력변환장치는 컴퓨터 시뮬레이션과 실험을 통하여 성능을 검증하였다.

• 대한전기학회논문지
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• 제45권3호
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• pp.358-364
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• 1996

Recently, much power demand from domestic power consumer is weakening the allowable power reserve margin in summer, especially at midday for one day due to a steep increase of air cooling loads such as air conditioner. Therefore solar airconditioning system can'be considered as one of the best remedies to meet the increase of peak power. Generally in solar air conditioning system, the diode rectifier is used to build up DC link voltage from AC source. The diode rectifier is simple and cheap but it brings out the problems of low power factor and plentiful harmonics at the AC source. Also It can derate the utilization rate of solar energy because the reverse of power flow cannot be made. Hence, in this paper to overcome the peak power problem in summer and to endure good AC input characteristics, solar air conditioning system using the PWM converter is proposed. As results, obtained are the characteristics of the PWM converter such as low distorted current waveform, high power factor and bidirectional power control. And also the stability of proposed system is verified by examining the dynamics of step load change and power reversal testing. (author). refs., figs., tabs.

• 조명전기설비학회논문지
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• 제12권4호
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• pp.100-105
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• 1998

본 논문은 고조파와 무효전력을 보상하는 전력용 능동펼터의 성능을 가지는 무정전 전원장치의 제어기볍올 제안 한다. 제안된 시스템은 단지 하나의 전력변환회로만올 가지고 AC/DC 정류기 및 배터리 충전기 그리고 인버터로서 동작할 수 있다. 더욱이 상용전원이 정상일 경우 제안된 시스템은 비선형 부하에 의해 발생된 고조파 및 무효 전 력올 보상하기 위해 전력용 능동필터 모드로 동작한다. 그리고 상용전원이 비정상일 경우는 인버터로 동작하여 배터리에 충전된 전력을 부하로 공급하는 배터리 방전전력 모드로 동작올 한다. 전력용 능동필터 모드에서 보상전류 를 정확히 계산하기 위한 새로운 폐-루프 방식을 제안한다. 마지막으로 제안된 5[kVA]급 시스템의 성능이 시뮬레이션과 실험결과들에 의해 입증된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.505-511
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• 2008

when electric traction system used DC 1500V runs on decline of rail road track and slows down, dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The purpose of this study was the development of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister. That is Developed regenerative inverter system returns the regenerative energy from the DC line voltage to the utility. In addition, the inverter can be compensate the harmonics caused by the power conversion devices used in the DC traction system.