检索结果-内蒙古大学图书馆

The stability postulate of N.G. Cetaev and the augmented model validation

IFAC-PapersOnLine 2017年第1期50卷 7450-7455页

作者： Răsvan V. Department of Automation and Electronics University of Craiova A.I.Cuza 13 Craiova RO-200585 Romania

The stability in the sense of Lyapunov turned to be a most important property for equilibria and global trajectories of the dynamical systems. The so-called Stability Postulate of N.G. Četaev states that only those trajectories and equilibria which are at least stable in the sense of Lyapunov are observable and measurable. On the other hand any mathematical model of some real (physical) process requires validation in order to be self consistent as a mathematical object, also to fit to data obtained from experiments (at least basically). Combining standard validation criteria for self consistency (existence, uniqueness, data dependence) with the Stability Postulate, also with other requirements will lead to the so-called augmented model validation for self consistency i.e. as a mathematical object. Since these new concepts (like the Stability Postulate) define a methodology they have to be checked on applications (as Četaev did). Therefore, there will be considered a case of energy co-generation described by conservation laws. © 2017

关键词： distributed parameters Energy control Model validation Stability Postulate

来源：评论

学校读者我要写书评

暂无评论

A Group of Single-Ended Time-Domain Line Fault Location Methods Using Breaker Operation Information

A Group of Single-Ended Time-Domain Line Fault Location Meth...

引用

IEEE-Power-and-Energy-Society General Meeting (PESGM)

作者： Duan, Mengzhao Liu, Yu Liu, Ze Zou, Xinchen Guan, Zhongtao ShanghaiTech Univ Sch Informat Sci & Technol Shanghai 201210 Peoples R China SJTU Minist Educ Key Lab Control Power Transmiss & Convers Shanghai 200240 Peoples R China

ISBN: (纸本)9781665464413

This paper proposes three single-ended time-domain fault location methods for AC transmission lines. The traditional impedance based single-ended fault location methods usually assume that the system is homogeneous or the remote source parameters are known, which are not always satisfied. In addition, the phasor measurements are required, which need a relatively long measurement time window (typically more than one cycle). The proposed methods utilize the additional information brought by the operation modes of circuit breakers. The proposed methods only require instantaneous voltage and current measurements at the local end, and do not need any remote side information. Specifically, the line models considering lumped or distributed parameters are utilized, formulating three fault location methods. The effectiveness of the proposed methods is verified via numerous case studies in PSCAD/EMTDC, with different fault types, locations and resistances, and the results prove that the method with full consideration of distributed parameters presents the best accuracy. The methods only require a short data window within half a cycle (10 ms) and a relatively low sampling rate of 4kHz.

关键词： Line fault location single-ended measurements time domain Bergeron model distributed parameters

来源：评论

学校读者我要写书评

暂无评论

PDE Observer Design for Counter-Current Heat Flows in a Heat-Exchanger

引用

IFAC-PapersOnLine 2017年第1期50卷 7127-7132页

作者： Zobiri F. Witrant E. Bonne F. Univ. Grenoble Alpes GIPSA-lab Grenoble France UMR-E 9004 CEA/Univ. Grenoble Alpes INAC SBT 17 rue des Martyrs Grenoble 38054 France

In this work, we consider the estimation of temperature profiles along the pipes of a plate heat exchanger. The transport phenomena through the heat exchanger are modeled by hyperbolic partial differential equations (PDE) of first order in time and space. The counter-flow heat exchange implies that the system is comprised of rightward (where the hot fluid circulates) and leftward (cold fluid pipes) hyperbolic PDE. The heat exchanged between the pipes of hot and cold fluid induces a coupling between the rightward and leftward equations, which increases the difficulty of solving the PDE system. The estimation objective is addressed by the design of an observer using a PDE approach, which uses boundary measurements to estimate the distributed profiles. The convergence of the observation error is established using Lyapunov analysis. Simulation results illustrate the efficiency of our method using a simulator with time-varying parameters validated on experimental data. © 2017

关键词： cryogenic temperatures distributed parameters heat exchangers Observers partial differential equations

来源：评论

学校读者我要写书评

暂无评论

Digital Simulation for Computer Control of Radiological Devices: A Preliminary Model Using Partial Differential Equations

引用

International Conference on Advancements of Medicine and Health Care Through Technology

作者： Roman, N. M. Colosi, H. Pusca, M. Tech Univ Cluj Napoca Baritiu 26 Cluj Napoca Romania Iuliu Hatieganu Univ Med & Pharm Cluj Napoca Romania

ISBN: (纸本)9783642042911

The paper presents an original method and its computer simulation results connected to specific details of radiation conduction from medical imaging or radiation therapy devices. The study is based on analogical modeling and digital simulation of processes with distributed parameters, described by equations with partial derivatives. A case study presented in this work simulates the process of radiation propagation from a medical device, offering the premises for future developments regarding computer controlled fine-tuning of radiological equipment.

关键词： Radiation conduction and therapy distributed parameters partial derivatives radiological equipment

来源：评论

学校读者我要写书评

暂无评论

M-Model: A New Precise Medium-Length Transmission Line Model

M-Model: A New Precise Medium-Length Transmission Line Model

引用

IEEE Canadian Conference on Electrical and Computer Engineering (CCECE)

作者： Al-Roomi, Ali R. El-Hawary, Mohamed E. Dalhousie Univ Dept Elect & Comp Engn 1459 Oxford St Halifax NS B3H 4R2 Canada

ISBN: (纸本)9781728154428

Real transmission lines are translated into mathematical models using either the lumped parameter approach or the distributed parameter approach. The first one is used for short- and medium-length transmission lines, while the other is used for long-length transmission lines where the accuracy and precision are required. For medium transmission lines, the lumped parameter approach can be applied using one of four popular circuit representations known as gamma (Gamma), opposite-gamma (Gamma), tee (T), and pi (Pi). This study presents a new circuit representation called em (M). This model is inspired by the sagging phenomenon where, at the sag point, the distributed series impedance of the Pi-model is divided into two equal/unequal parts and the distributed shunt admittance at the center is bigger than that at both ends. For some numerical experiments, the M-model shows a stunning performance in estimating transmission line readings. It wins in most cases and, for the few remaining cases, the M-model shows very competitive results.

关键词： telegrapher's equations distributed parameters lumped parameters transmission lines line modeling

来源：评论

学校读者我要写书评

暂无评论

Discrete-time state-space modeling of distributed parameter transmission line

Discrete-time state-space modeling of distributed parameter ...

引用

International Conference on Computer as a Tool (EUROCON 2007)

作者： Mamis, Mehmet Salih Inonu Univ Dept Elect & Elect Engn Malatya Turkey

ISBN: (纸本)9781424408122

This work presents a new approach for statespace modeling of distributed parameter transmission tine for transient analysis. The lossless line model based on the method of characteristics is used and the state equations are derived. These equations are converted to a set of difference equations using the trapezoidal rule of integration. By solving these equations, the state of system at discrete time points is obtained. An illustrative example is given and the obtained results are compared with those obtained using conventional methods based on s-domain and fast inverse Laplace transform (FILT). The study also investigates the effects caused by lumped parameter approximation of tine losses.

关键词： transmission lines state-space modeling distributed parameters transient analysis

来源：评论

学校读者我要写书评

暂无评论

Voltage distribution in stator windings of the motor driven by PWM inverter

Voltage distribution in stator windings of the motor driven ...

引用

International Conference on Power System Technology

作者： Wan, JR Liu, HC Yu, HJ Tianjin Univ Dept Elect Engn Tianjin 300072 Peoples R China

ISBN: (纸本)0780374592

Based on the distributed parameters circuit model of motor windings, time domain analysis is applied to get the function of the winding voltage that depends on time, voltage input and location of each turn. The software ANSYS for Finite Element Analysis (FEA) is used to analyze the electromagnetic field in stator slots of the motor. A model of a single slot is constructed;from which distributed inductance and distributed capacitance of each turn in the slot can be obtained. The results show the rules of distributed parameters of windings in different location of each turn. Lastly, using MATLAB simulation, this paper probes into the voltage distribution laws in turns and windings when the motor is driven by PWM pulse voltage, which founds the theoretical basis of premature failure of winding insulation.

关键词： PWM distributed parameters voltage distribution windings

来源：评论

学校读者我要写书评

暂无评论

PDE Observer Design for Counter-Current Heat Flows in a Heat-Exchanger

PDE Observer Design for Counter-Current Heat Flows in a Heat...

引用

20th World Congress of the International-Federation-of-Automatic-Control (IFAC)

作者： Zobiri, Fairouz Witrant, Emmanuel Bonne, Francois Univ Grenoble Alpes GIPSA Lab Grenoble France Univ Grenoble Alpes CEA UMR E9004 INACSBT 17 Rue Martyrs F-38054 Grenoble France

In this work, we consider the estimation of temperature profiles along the pipes of a plate heat exchanger. The transport phenomena through the heat exchanger are modeled by hyperbolic partial differential equations (PDE) of first order in time and space. The counter flow heat exchange implies that the system is comprised of rightward (where the hot fluid circulates) and leftward (cold fluid pipes) hyperbolic PDE. The heat exchanged between the pipes of hot and cold fluid induces a coupling between the rightward and leftward equations, which increases the difficulty of solving the PDE system. The estimation objective is addressed by the design of an observer using a PDE approach, which uses boundary measurements to estimate the distributed profiles. The convergence of the observation error is established using Lyapunov analysis. Simulation results illustrate the efficiency of our method using a simulator with time-varying parameters validated on experimental data. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Observers partial differential equations cryogenic temperatures heat exchangers distributed parameters

来源：评论

学校读者我要写书评

暂无评论

Pointwise Damping and Time Delay in the Stabilization of a Mechanical System 18th

Pointwise Damping and Time Delay in the Stabilization of a M...

引用

18th IFAC Workshop on Time Delay Systems (TDS)

作者： Danciu, Daniela Rasvan, Vladimir Univ Craiova Dept Automat & Elect AI Cuza Str 13 RO-200585 Craiova Romania Romanian Acad Engn Sci ASTR Dacia Blvd 26 RO-010413 Bucharest Romania

It is considered a mechanical system composed of a string in cantilever having a pointwise damping. The discontinuous B(oundary) V(alue) P(roblem) is split in two coupled BVPs. Introducing the Riemann invariants and taking into account their invariance along the characteristics, a system of continuous time difference equations with two delays is associated to the coupled BVPs and a one-to-one correspondence between the solutions of the two mathematical objects is proven. Then a theorem on exponential stability for the difference system is obtained. The stability depends on the arithmetic properties of the delay ratio. The aforementioned one-to-one correspondence is then used to establish exponential stability of the classical solutions of the coupled BVPs. Some conclusions and a sketch of open and future research subjects end the paper. Copyright (c) 2024 The Authors.

关键词： Linear control system distributed parameters time delay pointwise damping exponential stability

来源：评论

学校读者我要写书评

暂无评论

A Novel Approach to Precisely Calculate Lumped parameters for Transmission Lines with Sag Using the M-Model Equivalent Circuit

A Novel Approach to Precisely Calculate Lumped Parameters fo...

引用

IEEE Electric Power and Energy Conference (EPEC)

作者： Al-Roomi, Ali R. El-Hawary, Mohamed E. Dalhousie Univ Dept Elect & Comp Engn 1459 Oxford St Oxford NS B3H 4R2 Canada

ISBN: (纸本)9781728164892

Real transmission lines are exposed to dynamic weather conditions and operated under different system states. These changes force power cables to sag, and thus the values of their distributed series and shunt parameters vary as well. This study is an attempt to account for the variations in these parameters by using a new highly precise medium-length transmission line model called the M-model. This lumped circuit represents the changes in the shunt parameters by a variable slack admittance placed in the middle of the circuit and the changes in the series parameters by two variable series impedances. Two approaches are proposed in this paper to realize the lumped shunt admittance. The first one divides the line into three ideal parts and then calculates the shunt admittance of the middle part at an equivalent height. The second one takes the ratio of the area below the line before and after sag. These methods can directly solve the inherent weaknesses associated with temperature-dependent studies without the necessity to know any temperature coefficient.

关键词： line modeling distributed parameters lumped parameters sag lines line wings problem

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：