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5th IEEE Conference on Energy Internet and Energy system Integration, EI2 2021

作者： Luo, Yongyi Qing, Xianguo Peng, Renyong Huangfu, Yuzhao Cui, Ao Wang, Zhaosu Zhang, Zhiqiang Peng, Ziheng Liao, Chengyu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9781665434256

Modular multilevel converter (MMQ has many advantages, such as low loss, flexible control and so on, which has been widely used in photovoltaic grid connected system. However, the photovoltaic output has some instability, and the damping of the flexible DC system is also low, which puts forward a severe test for the stable operation of the power grid. Firstly, this paper describes the basic structure of the photovoltaic system connected by MMC. Secondly, the photovoltaic grid connected system model based on PSCAD illustrates the fault current characteristics under DC side fault, and simulates and analyzes the influence of different factors in the system on the fault current. © 2021 IEEE

关键词： Power converters

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Comparative study on thermal stress analysis and fatigue curve in stress and fatigue calculation of nuclear equipment 28

Comparative study on thermal stress analysis and fatigue cur...

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2021 28th International Conference on Nuclear Engineering, ICONE 2021

作者： Shao, Xuejiao Xie, Hai Yixiong, Y. Zhang, Liping Fu, Xiaolong Mi, Xue Li, Hui Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9780791885246

In the stress and fatigue evaluation of primary nuclear equipment, thermal stress calculation and fatigue curve have a great impact on the calculation results. There is a problem of stability in the step integral when calculating the thermal stress. The transient heat conduction changes rapidly near the initial temperature time point. It is critical to choose the right sub steps. In the nuclear code, the design fatigue curve in the air environment is given by applying a factor of 2 on stress or a factor of 20 on cycles. The factors are used to consider various influences such as data scatter, structure size, surface roughness and load. The factors of fatigue curves in ASME BPVC 2007 edition + 2009 addendum and French AFCEN's RCC-M 2017 edition RPP 2 have changed. Due to the changes of the original test data and modificative factors, the new fatigue curve and the original fatigue curve are crossed. In code case N-761 of ASME, fatigue curves considering the influence of primary coolant environment are given under different strain rates. In the calculation of thermal transient using commercial ANSYS software, the setting of time step has a great influence on the thermal stress. This paper compares and analyzes the influence of different calculation methods on the thermal stress at different positions of the model. The effect of different fatigue curves on fatigue life is also discussed considering different air design curve and different strain rate fatigue curve in water. The results show that the fatigue results obtained by using the modified ASME or RCC-M air fatigue curve are smaller than those before the change when the usage factor is large to a certain extent. After considering the environmental fatigue curve, the fatigue results increase significantly. The accuracy of thermal stress calculation can be significantly improved by adding time points and refining time steps near the time points after the transient sharply changes, otherwise the influence of thermal

关键词： Thermal stress

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Preliminary research on the thermal-mechanical coupling behavior simulation method of m3 fuel 28

Preliminary research on the thermal-mechanical coupling beha...

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2021 28th International Conference on Nuclear Engineering, ICONE 2021

作者： Changbing, Tang Yongjun, Jiao Yuanming, Li Kun, Zhang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institution of China Chengdu China

ISBN: (纸本)9780791885253

M3 fuel which microencapsulated TRISO particles in zirconium metal matrix is an integrated fuel designed to replace the traditional pellet-cladding fuel rod. The fuel design can effectively solve the problems of LWR fuel, such as water side corrosion, abrasion, pellet-cladding interaction, stress corrosion cracking and internal pressure bracing. Because of the multiple coating structure of TRISO particles and complex contacting behavior and deformation between TRISO particle and metal matrix, M3 fuel exhibits complex in-pile behavior. In order to establish the simulation method for the M3 fuel, the three-dimensional model was established by using ABAQUS software. The complex contacting behavior and deformation of coated layers and matrix for M3 fuel was considered. The results indicated that bonded strength between TRISO particle and Zr matrix has great effect on the stress distribution of SiC layer and matrix. The vulnerable area of Zr matrix located in the nearest position of TRISO particle to TRISO particle. The maximum tensile hoop stress of SiC layer was up to 150 MPa under strong bonding state, while SiC layer suffered compressive stress during all operation time for the weak bonding state. The failure probability of SiC layer was about 7 10-3 under strong bonding state which much higher than the weak ones. Thus, the integrity of SiC layer can be maintained by controlling the bonding strength between TRISO particle and Zr matrix during manufacturing process. © 2021 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Silicon carbide

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Forming Circle Formations of Multi-agent systems Under Actuator Faults 5th

Forming Circle Formations of Multi-agent Systems Under Actu...

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5th Chinese Conference on Swarm Intelligence and Cooperative Control, CCSICC 2021

作者： Liu, Jiajun Ru, Xinfeng Xia, Weiguo Wang, Chen China National Aeronautical Radio Electronic Research Institute and National Key Laboratory of Science and Technology on Avionics System Integration Shanghai China Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education and School of Control Science and Engineering Dalian University of Technology Dalian China National Engineering Research Center of Software Engineering and the State Key Laboratory of Turbulence and Complex Systems Intelligent Biomimetic Design Lab College of Engineering Peking University Beijing China

ISBN: (纸本)9789811939976

A distributed fault-tolerant formation control law is designed in this paper for multi-agent systems under external disturbances and actuator faults including time-varying loss of effectiveness faults. The initial position of each agent is already on a circle and the control purpose is to form a desired formation on this circle. Based on this local information, a distributed adaptive formation control law is designed by employing the congelation of variables method to deal with time-varying actuator faults. Finally, a simulation example is given to verify the effectiveness of the adaptive fault-tolerant control design method. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Multi agent systems

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design of Emulation system for Safety DCS 5th

Design of Emulation System for Safety DCS

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5th International Symposium on Software Reliability, Industrial Safety, Cyber Security and Physical Protection of Nuclear Power Plant, ISNPP 2020

作者： Peng, Hao Zhang, Xu Deng, Zhi-Guang Chen, Qi Zhang, Yu Jiang, Wei Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9789811634550

DCS (Digital Control system) is a very important part in safety protection in NPP (Nuclear Power Plant). Virtual DCS realizes the algorithm configuration of physical DCS running on general computers and gets rid of the limitation of hardware. In this paper, an emulation system (virtual DCS) is designed using virtual DPU technology. The virtual DCS can be used to verify the algorithm logic with the closed-loop system, which is composed by virtual DCS and digital reactor processing model together. The virtual DCS and controlled object are closed to test the control effects and in this way to verify the design of the NPP DCS. For the purpose of scientific research, training and design verification, virtual DCS should have malfunction simulation and other functions. These functions reflect the superiority of emulation technology. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Digital control systems

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Hybrid discontinuous Galerkin method for the hyperbolic linear Boltzmann transport equation for multiscale problems

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Physical Review E 2024年第6期110卷 065301-065301页

作者： Qizheng Sun Xiaojing Liu Xiang Chai Hui He Lianjie Wang Bin Zhang Tengfei Zhang School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China Shanghai Digital Nuclear Reactor Technology Fusion Innovation Center Shanghai Jiao Tong University Shanghai 200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China

We propose an upwind hybrid discontinuous Galerkin (HDG) method for the first-order hyperbolic linear Boltzmann transport equation, featuring a flexible expansion suitable for multiscale scenarios. Within the HDG scheme, primal variables and numerical traces are introduced within and along faces of elements, respectively, interconnected through projection matrices. Given the variables in two stages, the HDG method offers significant flexibility in the selection of spatial orders. The global matrix system in this framework is exclusively constructed from numerical traces, thereby effectively reducing the degrees of freedom (DoFs). Additionally, the matrix system in each discrete direction features a blocked-lower-triangular stencil, enhancing the efficiency of solving hyperbolic equations through an upwind sweep sequence. Based on the proposed method, we perform an asymptotic analysis of the upwind-HDG method in the thick diffusion limit. The result reveals that the correct convergence of the upwind-HDG is closely associated with the properties of the response matrix L. A series of numerical experiments, including comparisons with the even-parity HDG, confirms the accuracy and stability of the upwind-HDG method in managing thick diffusive regimes and multiscale heterogeneous problems.

关键词： Differential equations Finite-element method Mathematical physics methods Methods in transport

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In-situ TEM observation of the evolution of helium bubbles in Mo during He^(+)irradiation and post-irradiation annealing

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Chinese Physics B 2021年第8期30卷 102-112页

作者： Yi-Peng Li Guang Ran Xin-Yi Liu Xi Qiu Qing Han Wen-Jie Li Yi-Jia Guo College of Energy Xiamen UniversityXiamen 361102China Fujian Research Center for Nuclear Engineering Xiamen 361102China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The evolution of helium bubbles in purity Mo was investigated by in-situ transmission electron microscopy(TEM)during 30 keV He^(+)irradiation(at 673 K and 1173 K)and post-irradiation annealing(after 30 keV He^(+)irradiation with the fluence of 5.74×10^(16)He^(+)/cm^(2)at 673 K).Both He^(+)irradiation and subsequently annealing induced the initiation,aggregation,and growth of helium *** had a significant effect on the initiation and evolution of helium *** higher the irradiation temperature was,the larger the bubble size at the same irradiation fluence would *** 1173 K irradiation,helium bubbles nucleated and grew preferentially at grain boundaries and showed super large size,which would induce the formation of *** the same time,the geometry of helium bubbles changed from sphericity to *** polyhedral bubbles preferred to grow in the shape bounded by{100}*** statistical analysis of the characteristic parameters of helium bubbles,the functions between the average size,number density of helium bubbles,swelling rate and irradiation damage were ***,an empirical formula for calculating the size of helium bubbles during the annealing was also provided.

关键词： helium bubbles in-situ TEM observation ion irradiation annealing molybdenum

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Tuning the number of chiral edge channels in a fixed quantum anomalous Hall system

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Physical Review B 2024年第20期109卷 L201402-L201402页

作者： Peng Deng Yulei Han Peng Zhang Su Kong Chong Zhenhua Qiao Kang L. Wang Beijing Academy of Quantum Information Sciences Beijing 100193 China Department of Electrical and Computer Engineering University of California Los Angeles California 90095 USA Department of Physics Fuzhou University Fuzhou Fujian 350108 China International Center for Quantum Design of Functional Materials CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics University of Science and Technology of China Anhui 230026 China Hefei National Laboratory University of Science and Technology of China Hefei 230088 China

Quantum anomalous Hall (QAH) insulators exhibit chiral edge channels characterized by vanishing longitudinal conductance and quantized Hall conductance of Ce2/h, wherein the Chern number C is an integer equal to the number of the parallel chiral edge channels. These chiral edge channels conduct dissipationless transport in QAH insulators, making them pivotal for applications in low-consumption electronics and topological quantum computing. While the QAH effect with multiple chiral edge channels (i.e., C > 1) has been demonstrated in multilayers consisting of magnetic topological insulators and normal insulators, the channel number remains fixed for a given sample. Here, we unveil the tunability of the number of chiral edge channels within a single QAH insulator device. By tuning the magnetization of individual layers within the multilayer system, Chern insulating states with different Chern numbers are unveiled. The tunable Chern number was corroborated by our theoretical calculations. Furthermore, we conducted layer-dependent calculations to elucidate the contribution of the Chern number from different layers in the multilayer. Our findings demonstrate an extra degree of freedom in manipulating the chiral edge channels in QAH insulators. This tunability offers an extra dimension for the implementation of the QAH-based multichannel dissipationless transport.

关键词： Quantum anomalous Hall effect Quantum transport Topological insulators Molecular beam epitaxy

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Research on Distributed Measurement and Control system Based on FlexRay Bus 3

Research on Distributed Measurement and Control System Based...

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2022 3rd International Conference on Electrical technology and Automatic Control, ICETAC 2022

作者： Zhao, Xiaodong Yang, Fan Li, Wantong Li, Haiyuan National Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing China Unmanned System Research Institute Northwestern Polytechnical University Xi'an China

With the purpose of the design problem of electromagnetic launch distributed measurement and control system, this paper proposes a design method of scalable large-scale distributed interconnected measurement and control system based on FlexRay bus. The task execution time deviation of each node in the distributed system, including phase deviation and frequency deviation, is reduced by using the macro tick generation process and clock synchronization process to achieve task synchronization in the distributed system. The synchronization of timing generation is realized based on the universal clock technology. When the timing interval is zero, the pulse power units are guaranteed to be close to the ideal full synchronization, thus ensuring that the released energy during transmission is close to the design value. In the state of adjustable timing, when the pulse power supply module conducts pulse discharge, the trigger discharge times of the modules are set according to the load needs. The flat top, sawtooth, and other characteristic current waveforms are adjusted accurately. At the same time, a combined multi-level protection structure based on hardware and software is realized. The verification results show that the distributed electromagnetic launch measurement and control system implemented in this paper can meet the high efficiency, fast and continuous launch target. © Published under licence by IOP Publishing Ltd.

关键词： Synchronization

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Research on data assimilation strategy of turbulent separated flow over airfoil

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Applied Mathematics and Mechanics(English Edition) 2022年第4期43卷 571-586页

作者： Ying ZHANG Lin DU Weiwei ZHANG Zichen DENG National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Complex System Dynamics and Control Academic Exchange Center School of Mathematics and StatisticsNorthwestern Polytechnical UniversityXi'an 710119China Rotor Aerodynamics Key Laboratory China Aerodynamics Research and Development CenterMianyang 621000Sichuan ProvinceChina

In order to increase the accuracy of turbulence field reconstruction,this paper combines experimental observation and numerical simulation to develop and establish a data assimilation framework,and apply it to the study of S809 low-speed and high-angle airfoil *** method is based on the ensemble transform Kalman filter(ETKF)algorithm,which improves the disturbance strategy of the ensemble members and enhances the richness of the initial members by screening high flow field sensitivity constants,increasing the constant disturbance dimensions and designing a fine disturbance *** results show that the pressure distribution on the airfoil surface after assimilation is closer to the experimental value than that of the standard Spalart-Allmaras(S-A)*** separated vortex estimated by filtering is fuller,and the eddy viscosity field information is more abundant,which is physically consistent with the observation ***,the data assimilation method based on the improved ensemble strategy can more accurately and effectively describe complex turbulence phenomena.

关键词： turbulence data assimilation ensemble disturbance strategy large angle of attack separation ensemble transform Kalman filter(ETKF)

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