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Hao Lu,Changyi Wang,Haibao Guo,Hao Lv,Yimin Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3
A bogie frame is a key component of high-speed rail; higher requirements of the safety and stability of the bogie frame are put forward with the continuous improvement of the train speed. In this study, we first performed a strength analysis of a bogie frame according to the JIS E 4207 standard by using finite element method. Then, we did a reliability analysis of the bogie frame. The reliability problems are defined as strength reliability and resonant frequency reliability, which indicate the structural safety and stability of the bogie frame. The reliability estimation is realized by experimental design, artificial neural network and stochastic perturbation theory. Additionally, reliability-based sensitivity indices were derived to measure the parameter importance of random input variables. An illustrative example of the bogie frame with incomplete probabilistic information was used to demonstrate the applications of the proposed method for reliability and reliability-based sensitivity estimation in terms of strength and resonant frequency reliability. The results indicate that vertical loads and the material density have more of an impact on reliability than other variables of the bogie frame.
Cheng Zhiping,Wang Kaifang,Li Zhongwen,Wu Haotian,Zhi Changyi,Zhang Jinbin 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
In this paper, distributed secondary control of AC microgrid (MG) is studied and the infuence of communication delay on its control performance is analyzed and verifed. Firstly, a secondary control strategy for the MG is designed to achieve frequency recovery and proportional active power dispatch. Secondly, the stability of the MG system is analyzed in the frequency domain and a rigorous formula is derived to calculate the delay margin for the stability of the distributed secondary control with communication delays. The theoretical calculation results of the stability margin are approximately consistent with the simulation results, with an error of only 1.27%. The efects of the algorithm gains, communication topology, and connection weights on the delay margin are discussed based on the derived formula. The results demonstrate that the algorithm gain is inversely proportional to the delay margin. Changes in the communication topology and connection weights lead to changes in the maximum eigenvalue of the adjacency matrix L, which in turn afects the delay margin. Moreover, the infuence of time-varying delays is considered. The system can tolerate greater time-varying delays than fxed delays. Simulation and experimental results validate the efectiveness and feasibility of the proposed method.