This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicabi...This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength (fC =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N0=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (Ru) and the energy ratio (ES/EC ), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R u,cal and R u (Test), Maeda's formula shows severe deviation.展开更多
传统的开关器件脉频调制(Pulse Frequency Modulation,PFM)控制方法,存在开关频率高、频率不固定且稳定性能不好的缺点,使得它在APF的应用中增加了滤波器的设计难度。为此提出了以最优占空比为原则的改进脉频调制方法。该方法通过最小...传统的开关器件脉频调制(Pulse Frequency Modulation,PFM)控制方法,存在开关频率高、频率不固定且稳定性能不好的缺点,使得它在APF的应用中增加了滤波器的设计难度。为此提出了以最优占空比为原则的改进脉频调制方法。该方法通过最小二乘法获得最优占空比,并依此合理选择控制参数,且在控制器中,引入电网及补偿电压的实时特性,参与开关器件的导通时间、关断时间及滞环环宽的控制,从而实现定频、降损、提高控制精度及动态性能。通过对PFM的传统与改进控制策略的仿真与实验,验证了所提方法的有效性,且该方法易于控制电路的设计。展开更多
基金supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF) and funded by the Ministry of Education,Science and Technology (2011-0009227)
文摘This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength (fC =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N0=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (Ru) and the energy ratio (ES/EC ), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R u,cal and R u (Test), Maeda's formula shows severe deviation.
文摘传统的开关器件脉频调制(Pulse Frequency Modulation,PFM)控制方法,存在开关频率高、频率不固定且稳定性能不好的缺点,使得它在APF的应用中增加了滤波器的设计难度。为此提出了以最优占空比为原则的改进脉频调制方法。该方法通过最小二乘法获得最优占空比,并依此合理选择控制参数,且在控制器中,引入电网及补偿电压的实时特性,参与开关器件的导通时间、关断时间及滞环环宽的控制,从而实现定频、降损、提高控制精度及动态性能。通过对PFM的传统与改进控制策略的仿真与实验,验证了所提方法的有效性,且该方法易于控制电路的设计。
