• 전력전자학회논문지
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• 제12권4호
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• pp.285-290
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• 2007

연료전지 시스템은 가스양 등 연료전지의 입력조건 변동 시, 또는 부하 변동 시와 같은 외부적인 영향에 의해서 과도상태 전압 왜란이 발생할 수 있다. 본 논문에서는 연료전지 출력전압의 왜란 보상을 위해 Z-소스 인버터와 울트라커패시터를 포함한 다양한 연료전지 시스템 회로방식을 제안하였다. Z-소스 인버터의 구조는 매우 간단하며 DC/DC 컨버터의 사용 없이 스위칭 패턴만을 제어하여 전압을 승/강압 할 수 있는 특징을 갖고 있다. 2-소스 인버터와 울트라커패시터를 포함하여 제안된 여러 가지 회로방식을 시뮬레이션을 통하여 특성을 분석하고 실험을 통하여 확인하였으며, 제안된 시스템이 전압 왜란에 대해 안정된 응답을 갖는 것을 확인하였다.

• 전기학회논문지
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• 제61권2호
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• pp.199-208
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• 2012

This paper proposes a quasi Z-source DVR(Dynamic Voltage Restorer) system with a series connection of the output terminals, to compensate the voltage variations in the 6.6[kV]/60[Hz] power distribution system. The conventional DVR using one quasi Z-source AC-AC converter has the advantage which it can compensate the voltage variations without the need for the additional energy storage device such as a battery, but it is impossible to compensate for the 50[%] under voltage sags. To solve this problem, a DVR system using two quasi Z-source AC-AC converters with the series connection of the output terminals is proposed. By controlling the duty ratio D in the buck-boost mode, the proposed system can control the compensation voltage. For case verification of the proposed system, PSIM simulation is achieved. As a result, in case that the voltage sags-swells occur 10[%], 20[%], 60[%] in power distribution system, and, in case that the 50[%] under voltage sags-swells continuously occur, all case could compensate by the proposed system. Especially, the compensated voltage THD was examined under the condition of the 10[%]~50[%] voltage sags and the 20[${\Omega}$]~100[${\Omega}$] load changes. The compensated voltage THD was worse for the higher load resistances and more severe voltage sags. Finally, In case of the voltage swells compensation, the compensation factor has approached nearly 1 regardless of the load resistance changes, while the compensation factor of voltage sags was related to the load variations.