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Your search keyword '"Wei, Yuzhou"' showing total 17 results
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17 results on '"Wei, Yuzhou"'

1. Distributed Data-driven Unknown-input Observers

Author

Wei, Yuzhou, Disarò, Giorgia, Liu, Wenjie, Sun, Jian, Valcher, Maria Elena, and Wang, Gang

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

Unknown inputs related to, e.g., sensor aging, modeling errors, or device bias, represent a major concern in wireless sensor networks, as they degrade the state estimation performance. To improve the performance, unknown-input observers (UIOs) have been proposed. Most of the results available to design UIOs are based on explicit system models, which can be difficult or impossible to obtain in real-world applications. Data-driven techniques, on the other hand, have become a viable alternative for the design and analysis of unknown systems using only data. In this context, a novel data-driven distributed unknown-input observer (D-DUIO) for an unknown linear system is developed, which leverages solely some data collected offline, without any prior knowledge of the system matrices. In the paper, first, the design of a DUIO is investigated by resorting to a traditional model-based approach. By resorting to a Lyapunov equation, it is proved that under some conditions, the state estimates at all nodes of the DUIO achieve consensus and collectively converge to the state of the system. Moving to a data-driven approach, it is shown that the input/output/state trajectories of the system are compatible with the equations of a D-DUIO, and this allows, under suitable assumptions, to express the matrices of a possible DUIO in terms of the matrices of pre-collected data. Then, necessary and sufficient conditions for the existence of the proposed D-DUIO are given. Finally, the efficacy of the D-DUIO is illustrated by means of numerical examples.

Published
2024

3. TOPOLOGY OPTIMIZATION DESIGN OF HIGH SPEED EMU GEARBOX

Author

GAO Yang, QUE HongBo, BIAN Xiang, and WEI YuZhou

Subjects
High-speed EMU gearbox, FEM, Topology optimization, Natural frequency, Modal test, Mechanical engineering and machinery, TJ1-1570, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

As the core component of high-speed EMU bogie, gearbox should meet the requirements of lightweight and high reliability in order to ensure the safety and comfort of vehicle operation. Taking the gearbox of a domestic high-speed EMU as the research object, the existing problems of the gearbox are analyzed by finite element method, then using the topology optimization technology to improve the design of the box structure. The results of finite element analysis show that the stiffness and strength of the gearbox meet the requirements under various working conditions. But it’s natural frequency is close to the main vibration frequency of wheel shaft system, which may cause resonance that leading to noise and box cracks. According to this characteristic, a topology optimization scheme is proposed to increase the natural frequency of the box. Verified by calculation and modal test, the natural frequency of the gearbox after topology optimization is raised to an interval that avoiding the main vibration frequency of wheel shaft system and reducing the possibility of resonance. The research in this paper provides theoretical and data support for the design of high-speed EMU gearbox with good static and dynamic characteristics.

Published
2022
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5. Data-Driven Distributed Information-Weighted Consensus Filtering in Discrete-Time Sensor Networks With Switching Topologies

Author

Ji, Honghai, Wei, Yuzhou, Fan, Lingling, Liu, Shida, Hou, Zhongsheng, and Wang, Li

Abstract

This article proposes a data-driven distributed filtering method based on the consensus protocol and information-weighted strategy for discrete-time sensor networks with switching topologies. By introducing a data-driven method, a linear-like state equation is designed by utilizing only the input and output (I/O) data without a controlled object model. In the identification step, data-driven adaptive optimization recursive identification (DD-AORI) is exploited to identify the recurrence of time-varying parameters. It is proved that for discrete-time switching networks, estimation errors of all nodes are ultimately bounded when data-driven distributed information-weighted consensus filtering (DD-DICF) is executed. The algorithm combines with the received neighbors and direct or indirect observations for the target node to produce modified gains, resulting in a novel state estimator containing an information interaction mechanism. Subsequently, convergence analysis is performed on the basis of the Lyapunov equation to guarantee the boundedness of DD-DICF estimate error. Simulations verify the performance of the DD-DICF against the theoretical results as well as in comparison with some existing filtering algorithms.

Published
2023
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7. Experimental Study on the Gas Bubble Temperature Around an Arc Under Insulation Oil

Author

Xu Che, Liu Hao, Yan Chenguang, Xu Ya, Zhu Shuyou, Zhou Xian, Baohui Zhang, Yifei Wu, and Wei Yuzhou

Subjects
Materials science, 020209 energy, Bubble, Energy Engineering and Power Technology, 02 engineering and technology, Mechanics, Polytropic process, Fault (power engineering), Temperature measurement, Isothermal process, Physics::Fluid Dynamics, Arc (geometry), Electric arc, Infrared thermometer, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering
Abstract

The internal temperature of a gas bubble caused by a fault arc is a key basic parameter for investigating the bubble behavior and the pressure rise inside oil-filled power equipment. Due to the constraints imposed by the measurement methods and experimental conditions, this temperature has always been estimated as a constant value of 2000 K in past decades. In this letter, we present direct experimental evidence of the gas bubble temperature around an arc. A large oil-filled transformer was reformed and used to conduct arcing fault tests. A sapphire fiber optic infrared thermometer was established and used to detect the internal gas bubble temperature. The experimental results confirm that this internal temperature is not constant but rather varies over a wide range from 2100 K to 1500 K, plummeting with rapid bubble growth and then exhibiting small variations until arc extinction. Furthermore, the bubble growth process throughout the arc duration can be approximately regarded as first polytropic and then isothermal.

Published
2021

13. Simulation and Analysis of Power Transformer Winding Vibration and Deformation under External Short-circuit Faults

Author

Xu Ya, Yan Chenguang, Liu Hao, Xu Che, Zhou Xian, Wei Yuzhou, and Baohui Zhang

Subjects
010302 applied physics, Electromagnetic field, Engineering, Short circuit fault, business.industry, Hardware_PERFORMANCEANDRELIABILITY, Structural engineering, 01 natural sciences, Finite element method, law.invention, Vibration, law, 0103 physical sciences, Structure design, Fe model, 010306 general physics, Transformer, business, Short circuit
Abstract

The transformer winding deformation and the insulation damage will occur under the impact of huge electromagnetic forces caused by the short circuit faults. In this paper, the electromagnetic-mechanical (E-M) field coupling 3D FE model was used for analyzing the transient characteristics of power transformer under short circuit faults. Considering the process of the transformer winding suffering short circuit current is a complicated multi-field coupling problem, this paper explores the inter-relationship between the short circuit fault topology, electromagnetic field and the mechanical field. Both the mathematical model of each field involved and the E-M field coupling model have been built. By the use of 3D FEM, the transient characteristics such as the electromagnetic forces, stress distribution and displacement of the transformer model have been calculated and simulated. Additionally, by analyzing the results from the simulation example, the radial and axial forces characteristics and the structure design suggestion for the winding have been obtained and proposed.

Published
2019

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