http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
배열회수보일러 케이싱 파손방지를 위한 열응력 저감 Heat Sink 설치 효과
최석민(Seok Min Choi),김선호(Seon Ho Kim),김풍일(Poongil Kim),고석재(Seok Jae Ko),정희봉(Hee Bong Chung),한봉기(Bong Gi Han),조형희(Hyung Hee Cho) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
This study investigate thermal stress on the HRSG casing adopting heat sink by experimental data and numerical simulation. Heat sink is adopted on the HRSG casing to reduce the thermal stress. Thermocouples are installed on the operating HRSG casing to measure the temperature. Measured data shows that temperature gradient is rapid on the middle section of the HRSG casing. On the middle section, the temperature gradient is average 100℃ and it will cause extreme thermal stress. By numerical simulation we found out the local temperature data and measeared the thermal stress on the HRSG casing. Thermal stress on the middle section of HRSG casing is the highest and we can easily assume that the breakages are frequently happens on that position. So, we installed the heat sink on the vulnerable position on the HRSG casing to reduce the thermal stress. By installing the heat sink, we can reduce the peak thermal stress by 10% on the vulnerable position. As a result, heat sink can reduce the thermal stress on the HRSG casing.
Cascaded 멀티레벨 인버터의 고장 허용 제어를 위한 Level-Shifted PWM 기반의 새로운 변조 기법
김석민(Seok-Min Kim),이준석(June-Seok Lee),이교범(Kyo-Beum Lee) 대한전기학회 2015 전기학회논문지 Vol.64 No.5
This paper proposes a novel level-shifted PWM (LS-PWM) strategy for fault tolerant cascaded multilevel inverter. Most proposed fault-tolerant operation methods in many of studies are based on a phase-shifted PWM (PS-PWM) method. To apply these methods to multilevel inverter systems using LS-PWM, two additional steps will be implemented. During the occurrence of a single-inverter-cell fault, the carrier bands scheme is reconfigured and modulation levels of inverter cells are reassigned in this proposed fault-tolerant operation. The proposed strategy performs balanced three-phase line-to-line voltages and line currents when a switching device fault occurs in a cascaded multilevel inverter using LS-PWM. Simulation and experimental results are included in the paper to verify the proposed method.