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Periodica polytechnica electrical engineering and computer science 2014年第4期58卷 133-148页

作者： Vízer, Dániel Mercère, Guillaume Prot, Olivier Laroche, Edouard Department of Control Engineering and Informatics Faculty of Electrical Engineering and Informatics Budapest University of Technology and Economics Magyar Tudósok krt. 1-3. BudapestH-1117 Hungary Laboratoire d'Informatique et d'Automatique Pour Les Systèmes University of Poitiers rue P. Brousse bâtiment B25 TSA 41105 Poitiers Cedex 986073 France Institut de Recherche XLIM University of Limoges 123 avenue A. Thomas Limoges Cedex87060 France University of Strasbourg Laboratoire des Sciences de l'Ingénieur De l'Informatique et de l'Imagerie 300 bd Sébastien Brant CS 10413 Illkirch Cedex10413 France

Identifying a linear parameter-varying (LPV) model of a nonlinear system from local experimental data is still a problem which deserves attention. Many difficulties related to the determination of the local models with respect to coherent bases have been recently pointed out and must be solved in order to ensure a good behavior of the interpolated LPV model. Rather than building a model either from the law of physics or from experimental data independently, the combination of an analytic and an experimental approach is used in this paper to identify an LPV model of a flexible robotic manipulator. This technique focuses on the interpolation step by combining local re-structured linear time-invariant (LTI) state-space models satisfying a state-space parameterization deduced from the non-linear equations governing the dynamic behavior of the system. A dedicated H∞-norm technique is introduced to solve the underlying re-structuring problem. This contribution shows that prior information can be really helpful when the problem of coherent basis selection arises. As a sample, the case of the identification of a 2-DoF non-linear flexible manipulator is addressed.

关键词： Flexible manipulators

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Fault detection and isolation problem: Sliding mode fuzzy observers and neural networks

Fault detection and isolation problem: Sliding mode fuzzy ob...

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International Conference on electrical engineering, Computing Science and automatic control (CCE)

作者： Juan Anzurez-Marin Elisa Espinosa-Juárez Bernardino Castillo-Toledo Electrical Engineering Faculty Universidad Michoacana de San Nicolás de Hidalgo Morelia Michoacán México Department of Automatic Control CINVESTAV-IPN Unidad Guadalajara Guadalajara Jalisco México

In this paper results of the application of a hybrid Fault Detection and Isolation scheme are presented. A Takagi-Sugeno fuzzy model is used to describe the system and a type of sliding mode observers are designed to estimate the system state vector; from this, the diagnostic signal-residual is generated by the comparison of measured and estimated output. Neural Networks are proposed in order to solve the fault isolation problem based on signal-residual. The faulted component is identified from the active signal-residuals by means of the application of the presented technique based on neural networks. This paper shows an application of the fault diagnosis technique, which was satisfactorily tested in a two-tank hydraulic system.

关键词： Observers Neural networks Vectors Fault diagnosis Mathematical model Takagi-Sugeno model electrical engineering

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The influence of the stator geometry on magnetic bearing parameters

The influence of the stator geometry on magnetic bearing par...

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作者： Tomczuk, Bronislaw Wajnert, Dawid Faculty of Electrical Engineering Automatic Control and Informatics Opole University of Technology ul. Prószkowska 76 45-758 Opole Poland

This paper presents an analysis of the stator teeth geometry impact on the parameters of the 8-pole radial magnetic bearing. In this paper, such parameters as current gain and position stiffness have been analysed. Additionally, we have proposed criteria for evaluating the characteristics of these parameters by calculating the variability of current gain and position stiffness. The research has been performed by solving the magnetic bearing actuator boundary problem using the finite element method. Magnetic force has been calculated using the Maxwell stress tensor method. Other parameters, such as current gain and position stiffness have been calculated as partial derivate of the force with respect to control current and position of the rotor.

关键词： Finite element method

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The influence of ultrasound signal parameters on sonoluminescence light intensity

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Archives of electrical engineering 2013年第4期62卷 605-612页

作者： Szmechta, Marek Boczar, Tomasz Zmarzly, Dariusz Faculty of Electrical Engineering Automatic Control and Computer Science Institute of Electric Power Engineering Opole University of Technology Prószkowska 76 45-758 Opole Poland

Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of electrical Power engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn't prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

关键词： Sonoluminescence

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Discrete-time sliding mode direct power control for three-phase grid connected multilevel inverter

Discrete-time sliding mode direct power control for three-ph...

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2013 4th International Conference on Power engineering, Energy and electrical Drives, POWERENG 2013

作者： Huseinbegović, Senad Peruničić-Draženović, Branislava Department of Automatic Control and Electronics Faculty of Electrical Engineering University of Sarajevo Sarajevo Bosnia and Herzegovina

ISBN: (纸本)9781467363921

This paper presents a novel Direct Power control strategy for a three-phase grid connected multilevel inverter. The proposed DPC strategy combines discrete-time sliding mode control and predictive control. The active and reactive power are directly controlled by inverter switching states, represented by a switching vector, using the value of the power error computed from samples of phase voltages and currents. An appropriate switching vector is selected for each sampling period to minimize average value of the switching functions on the time interval on three sampling periods. The prediction of phase voltages and currents is necessary for algorithm implementation. The switching frequency is constant, and the digital control implementation is simple. The designed control system is tested using a simulation model of a three-level neutral-point clamped multilevel inverter. Simulation results confirm the design aims. © 2013 IEEE.

关键词： Sliding mode control

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Application of multi-comparational algorithms to classification of acoustic emission signals generated by partial discharges

Application of multi-comparational algorithms to classificat...

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IEEE Workshop on Signal Processing Systems (SIPS)

作者： Tomasz Boczar Dariusz Zmarzly Sebastian Borucki Andrzej Cichoń Paweł Frqcz Paweł Kurtasz Faculty of Electrical Engineering Automatic Control and Informatics Poland Opole University of Technology in Opole Poland Faculty of Electrical Engineering Automatic Control and Informatics

This article concerned on the mechanism of functioning of two multi-comparational algorithms, that is: CMCA (Classic Multi-Comparational Algorithm) and OMCA (Optimised Multi-Comparational Algorithm). The range and possibility of application of frequency descriptors that explicitly characterise the acoustic emission (AE) signals from partial discharges (PD) were described. The method for selection of quantity of the standard waveforms for the purpose of the classification process, carried out using the tested algorithms was presented. In addition, there were showed results of the simulation, performed using the proposed algorithms and two databases containing the AE signal waveforms generated by basic forms of PD, which can occur in insulation systems of transformers. The efficiency of CMCA and OMCA algorithms in application for AE signals generated by PD, as well as the reason to complete the developed database by another class of waveforms due to the defect of insulation system that not being catalogued previously was demonstrated in the study.

关键词： Classification algorithms Algorithm design and analysis Partial discharges Insulation Standards Discharges (electric) Databases

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Decomposition and projection methods for distributed robustness analysis of interconnected uncertain systems?

Decomposition and projection methods for distributed robustn...

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13th IFAC Symposium on Large Scale Complex Systems: Theory and Applications, LSS 2013

作者： Pakazad, Sina Khoshfetrat Andersen, Martin S. Hansson, Anders Rantzer, Anders Division of Automatic Control Department of Electrical Engineering Linkoping University Sweden Department of Informatics and Mathematical Modeling Technical University of Denmark Denmark Department of Automatic Control Lund University Sweden

We consider a class of convex feasibility problems where the constraints that describe the feasible set are loosely coupled. These problems arise in robust stability analysis of large, weakly interconnected uncertain systems. To facilitate distributed implementation of robust stability analysis of such systems, we describe two algorithms based on decomposition and simultaneous projections. The first algorithm is a nonlinear variant of Cimmino's mean projection algorithm, but by taking the structure of the constraints into account, we can obtain a faster rate of convergence. The second algorithm is devised by applying the alternating direction method of multipliers to a convex minimization reformulation of the convex feasibility problem. Numerical results are then used to show that both algorithms require far less iterations than the accelerated nonlinear Cimmino algorithm. © IFAC.

关键词： Algorithms

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The analysis of wind turbine construction safety system that uses vibroacoustic diagnostics

The analysis of wind turbine construction safety system that...

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作者： Szmechta, M. Department of Electrical Engineering Automatic Control and Informatics Opole University of Technology Prószkowska 76 45-758 Opole Poland

The paper presents an analysis of the results of monitored on-line Enercon E40/6.44 wind turbine with gearless designed synchronous generator and a nominal power of 600 kW. In recent months, this plant underwent with high frequency emergency stopped, the source of which was the acceleration control system located in the nacelle. This situation causes significant and unnecessary overload of the power plant components but most of all causes significant losses of production of renewable energy due to operational downtime. This article analyzes the circumstances of errors reported by the turbine control system associated with the acceleration sensor based on data recorded during several months of using on-line SCADA system. An assessment of the impact of a number of indicators related to the wind speed and direction of the nacelle on the operation of the safety system of the turbine has been carried out. Also the possible causes of irregularities were proposed, which may be the subject of further research, especially with the use of advanced diagnostics based on vibroacoustic method.

关键词： Wind turbines

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Comparison of various improved-partition fuzzy c-means clustering algorithms in fast color reduction

Comparison of various improved-partition fuzzy c-means clust...

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International Symposium on Intelligent Systems and informatics (SISY)

作者： László Szilágyi Géllert Dénesi Levente Kovács Sándor M. Szilágyi Dept. of Electrical Engineering Sapientia University Romania Dept. of Control Engineering and Information Technology Budapest University of Technology and Economics Budapest Hungary Dept. of Electrical Engineering Sapientia University Calea Sighiÿoarei l/C 540485 Tirgu Muteÿ Romania John von Neumann Faculty of Informatics Obuda Univesity Budapest Hungary Dept. of Informatics Petru Maior Univesity Tirgu Mureÿ Romania

This paper provides a comparative study of several enhanced versions of the fuzzy c-means clustering algorithm in an application of histogram-based image color reduction. A common preprocessing is performed before clustering, consisting of a preliminary color quantization, histogram extraction and selection of frequently occurring colors of the image. These selected colors will be clustered by tested c-means algorithms. Clustering is followed by another common step, which creates the output image. Besides conventional hard (HCM) and fuzzy c-means (FCM) clustering, the so-called generalized improved partition FCM algorithm, and several versions of the suppressed FCM (s-FCM) in its conventional and generalized form, are included in this study. Accuracy is measured as the average color difference between pixels of the input and output image, while efficiency is mostly characterized by the total runtime of the performed color reduction. Numerical evaluation found all enhanced FCM algorithms more accurate, and four out of seven enhanced algorithms faster than FCM. All tested algorithms can create reduced color images of acceptable quality.

关键词： Image color analysis Clustering algorithms Partitioning algorithms Accuracy Prototypes Quantization (signal) Vectors

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Frequency analysis of micro wind turbine vibrations using the MUSIC method

Frequency analysis of micro wind turbine vibrations using th...

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International Conference on Environment and electrical engineering

作者： Daria Wotzka Tomasz Boczar Faculty of Electrical Engineering Automatic Control and Informatics Opole University of Technology

ISBN: (纸本)9781467330602

Analysis results of vibro-acoustic signals generated by operation of a micro wind turbine that is installed on the roof of Electric Power Institute, Opole University of Technology are presented in the paper. Mast vibrations of the turbine under study have been measured under different weather conditions, i.e. by various wind speeds. A frequency analysis by use of the MUSIC method was performed. Shown results depict changes of frequency components appearing in the spectrum of the measured signals.

关键词： Microwind turbine Vibrations MUSIC analysis

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