ChungYeon Won

In this paper a fuel cell system with Z-source inverter and ultracapacitors for voltage sag compensation is proposed. The structure of Z-source inverter is simple. It has unique features that can boost without a DC/DC converter using only a modified switching pattern. Fuel cells have unique output characteristics. The fuel cell system can experience start-up transient and voltage sag. Simulation results show that the proposed fuel cell system with Z-source inverter and ultracapacitors is capable

Buildings in high-income, industrialized cities are responsible for more than 50% of global energy consumption; consequently, many developed cities have legislated energy benchmarking and disclosure policies to understand their buildings’ energy-use dynamics better. By utilizing these benchmarking data and additional information taken from 3D models, this paper presents a comprehensive analysis of large-scale office buildings located in New York and Chicago, with respect to their energy use inte

Although interest in and the importance of green building certification have increased, it is difficult to determine how much less energy the buildings actually consume after obtaining sustainability related certification, such as LEED in the USA, and G-SEED in Korea. Focusing on building energy evaluation, we compared and analyzed the energy evaluation items of LEED and G-SEED. In addition, from the Korean public data portal site, this study investigated the annual site energy consumption (elec

In this paper, new topology is proposed that can dramatically reduce the converter power rating and increase the efficiency of total PV system. Since the output voltage of PV module has very wide voltage range, in general, the DC/DC converter is used to get constant high DC voltage. According to analysis of PV characteristics, in proposed topology, only 20% power of total PV system power is needed for DC/DC converter. DC/DC converter used in proposed topology has flat efficiency curve at all loa

Purpose: Korea, one of the countries with most built high-rise buildings, and many densified urban mega-blocks continue to refine its planning regulations and approval process with room for improvement. Meanwhile, recent year’s acceleration of high-rise building construction across the globe has brought attention from many academic researchers and policy-makers around the world for developing design guidelines and policies that will ensure responsible high-rise, high-density developments. Purpos

기후변화로 홍수가 심화됨에 따라 규제가 건축 설계에 미치는 영향을 파악하는 것이 중요하다. 본 연구는 미국과 영국의 홍수위험 규제 하에서 수행된 주거·비주거 사례 10건을 분석하여 규제–설계 연계성과 국내 시사점을 도출하였다. 고상화·이격, 저감·저류, 차수·방호의 아홉 요소를 검토한 결과, 규제가 강할수록 설계 대응이 정교하며 일부 사례는 최소 기준을 초과해 규제가 혁신을 유도함을 확인하였다. 본 결과는 국내 홍수취약지역의 설계 지침과 정책 개선에 기초가 될 수 있다.

【In this paper, we study a series active power filter to compensate current harmonics and unbalanced source voltages. Conventional control methods for compensating unbalanced source voltages use source voltages to calculate compensation voltages, and in addition use load voltages to regulate load voltages. But the proposed control method uses load voltage to compensate unbalanced source voltages and regulate load voltages. And we propose a control method to reduce current harmonics which can cal