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Electrical double-layer capacitors diagnosis using least square estimation method

ELECTRIC POWER SYSTEMS RESEARCH 2014年 117卷 69-75页

作者： Oukaour, A. Omar, N. Gualous, H. Rachid, A. Van den Bossche, P. Van Mierlo, J. Univ Caen Basse Normandie EA 4253 F-50130 Octeville France Vrije Univ Brussel B-1050 Brussels Belgium Univ Picardie Jules Vernes F-80000 Amiens France

This paper deals with the electrical double-layer capacitor's (EDLC) aging diagnosis for electric and hybrid vehicles. It has been shown in the literature that the aging of EDLCs is related to the constraints undergone by the component such as EDLC voltage (V-sc) combined with the operating temperature. The results of several studies show that the best indicators of the EDLCs aging are the capacitance and the equivalent series resistance. Some experimental methods allow the identification of these parameters but they are time consuming and cannot be embedded. This study presents a new method to estimate the EDLC parameters using least square algorithm based on data measurements of input/output of the system. In order to perform the aging test, a test bench is developed. EDLCs are aged at constant temperature and constant voltage. They are placed inside a climatic chamber at 70 degrees C and polarized at 2.9 V during the aging process. To quantify the EDLC aging, the equivalent series resistance and the equivalent capacitance are measured. (C) 2014 Elsevier B.V. All rights reserved.

关键词： EDLC aging EDLC diagnosis EDLC parameters estimation EDLC modeling least square algorithm Runge-Kutta algorithm

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ARMAX Time Delay Systems Identification Based on least square Approach

ARMAX Time Delay Systems Identification Based on Least Squar...

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17th IFAC Symposium on System Identification (SYSID 2015)

作者： Bedoui, Saida Abderrahim, Kamel Gabes Univ Natl Engn Sch Gabes Res Unit Numer Control Ind Proc Route MedenineBP 6029 Gabes Tunisia

In this paper, an algorithm is developed for the identification of the time delay parameter and the dynamic parameters of autoregressive moving average with exogenous input ARMAX time delay models. This algorithm consists in constructing a linear-parameter formulation by building a generalized vector observation and using the recursive least squares approach to solve the obtained system. Simulation and experimental test results are presented to illustrate the performance of the proposed approach. (C) 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Time Delay Systems System Identification Discrete-time least square algorithm

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A NUMERICAL TECHNIQUE TO EVALUATE THE FLEXURAL STIFFNESS OF LONG BONES AFFECTED BY CRACKS AND POROSITY

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JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 2011年第1期11卷 131-148页

作者： Mohammadi, Hadi Bahramian, Fereshteh Mequanint, Kibret Rizkalla, Amin Univ Western Ontario Biomed Engn Grad Program London ON N6A 5B9 Canada Univ Western Ontario Dept Chem & Biochem Engn London ON N6A 5B9 Canada

Bone maintains its structure through a constant process of resorption and formation, in a process called bone remodeling. An imbalance in this process caused by disease, abnormal mechanical demands, or fatigue may predispose bone to fracture injuries. Increase in bone resorption can increase the number of surface cracks and structural porosity of the bone and thus change its stiffness properties. In this study, a computational technique is proposed to investigate the stiffness properties in long bones based on dynamic responses. As the first attempt, defects such as porosity and cracks are detected based on changes in stiffness properties of the sample. The least square algorithm and the finite element method are used as tools in this study. The Wilson-theta numerical method is employed to generate artificially experimental results for acceleration vectors. The data obtained from the artificial experiment is later employed to the proposed computational investigation model as raw data.

关键词： Finite element method finite difference method least square algorithm long bones dynamic response

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Polarization Tracking in the Presence of PDL and Fast Temporal Drift

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2022年第19期40卷 6408-6416页

作者： Farsi, Mohammad Hager, Christian Karlsson, Magnus Agrell, Erik Chalmers Univ Technol Dept Elect Engn SE-41296 Gothenburg Sweden Chalmers Univ Technol Dept Microtechnol & Nanosci SE-41296 Gothenburg Sweden

In this paper, we analyze the effectiveness of polarization tracking algorithms in optical transmission systems suffering from fast state of polarization (SOP) rotations and polarization-dependent loss (PDL). While most of the gradient descent (GD)-based algorithms in the literature may require step size adjustment when the channel condition changes, we propose tracking algorithms that can perform similarly or better without parameter tuning. Numerical simulation results show higher robustness of the proposed algorithms to SOP and PDL drift compared to GD-based algorithms, making them promising candidates to be used in aerial fiber links where the SOP can potentially drift rapidly, and therefore becomes challenging to track.

关键词： Signal processing algorithms Channel estimation Symbols Optical fiber dispersion Optical polarization Optical fiber amplifiers Optical fiber couplers Constant modulus algorithm hybrid algorithm least square algorithm polarization-dependent loss polarization tracking state of polarization

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A New and Fast Method for On-line Estimation of d and q Axes Inductances of Interior Permanent Magnet Synchronous Machines Using Measurements of Current Derivatives and Inverter DC-Bus Voltage

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2019年第10期66卷 7488-7497页

作者： Bui, Minh Xuan Rahman, M. Faz Guan, Deqi Xiao, Dan Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

This paper proposes a novel on-line technique for estimation of the inductances of an interior permanent magnet synchronous machine (IPMSM) based on the measurement of dc-bus voltage of the inverter and the stator current derivatives at certain voltage vectors during each pulsewidth modulation (PWM) cycle. This technique removes the requirement for the bulky and expensive shaft-locking mechanisms and test signal injection for obtaining the machine dq inductance parameters off line. It also overcomes the problems associated with other recursive on-line techniques which take a number of PWM cycles to update the parameters. The proposed method estimates the d and q axes inductances of IPMSMs within each PWM cycle without requiring knowledge of stator resistance, rotor flux linkage, and rotor speed. It also tracks the variations of the inductances (especially the q-axis inductance), which vary significantly due to q-axis magnetic saturation and cross saturation effect of the IPMSM, with sufficient accuracy. This paper presents full analysis, system simulation, and extensive experimental studies in order to verify the accuracy, quick tracking ability, and robustness of the proposed method.

关键词： Current derivative measurement interior permanent magnet synchronous machine (IPMSM) least square algorithm on-line inductance estimation SVPWM

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Multiparameter Estimation of IPMSMs Using Core Loss Current Calculations in dq-Axis Equivalent Circuit Model

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IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 2023年第2期59卷 1295-1306页

作者： Cheng, Hongfu Toulabi, Mohammad Sedigh Deshpande, Uday Kar, Narayan C. Univ Windsor Windsor ON N9B 3P4 Canada D&V Elect Ltd Toronto ON L4H 2Y7 Canada

Accurate parameter estimation is critical for high-performance modeling and control of interior permanent magnet synchronous machines (IPMSMs). Core loss effects affect the accuracy of the parameter estimation, especially in high loading conditions with saturated cores. Existing research on parameter estimation considering core loss effects generally focuses on the core loss equivalent resistance estimation;however, they require either accurate core loss experimental data or finite element analysis (FEA) model. The core loss equivalent resistance is dependent on the loading conditions, harmonics, frequency, and temperature, which increases the difficulty of accurately estimating the resistance. This article firstly proposes a direct core loss equivalent current estimation method for multiparameter estimation purposes without estimating the core loss equivalent resistance. Based on the estimated core loss equivalent currents, the dq-axis inductances equivalent currents are calculated to perform the multiparameter estimation. The proposed approach can improve the precision of the parameter estimation and the computation efficiency by calculating the core loss equivalent resistance currents without having the core loss data. The effectiveness of the proposed multiparameter estimation method is evaluated by comparing the calculated and measured torques of a laboratory 4.5 kW IPMSM in various operating conditions. The improved accuracy of the proposed method is verified by comparing it with two existing online parameter estimation methods and FEA-based offline parameter estimation results.

关键词： Core loss decoupled parameter estimation least square algorithm magnetic saturation VSI nonlinearity

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Damage Identification in a Plate Structure Based on Strain Statistical Moment

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ADVANCES IN STRUCTURAL ENGINEERING 2014年第11期17卷 1639-1655页

作者： Xiang, Wei Wang, Dansheng Zhu, Hongping Huazhong Univ Sci & Technol Sch Civil Engn & Mech Wuhan 430074 Peoples R China

The fourth strain statistical moment (FSSM) based damage detection method has been recently proposed by the authors and the results of numerical study demonstrated the proposed method is sensitive to local structural damage but insensitive to measurement noise for beam-type structure. In this paper, the method is extended to a plate structure. The method consists of two steps: damage localization and damage quantification. First, the damage is located by using the difference curved surfaces of FSSMs in one direction of a plate subjected to Gauss White Noise (GWN) excitation before and after damage. Then the model updating method based on least square algorithm is used to estimate the damage severities. Also, the numerical (finite element) simulations are carried out for a simply supported plate. The results demonstrate the proposed method can provide good prediction of both location and severity of damage at one or more sites, even under low damage severities and high measurement noise conditions.

关键词： damage identification fourth strain statistical moment (FSSM) finite element method thin plate least square algorithm

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A novel model for diffusion based release kinetics using an inverse numerical method

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MEDICAL ENGINEERING & PHYSICS 2011年第8期33卷 893-899页

作者： Mohammadi, Hadi Herzog, Walter Univ Calgary Fac Kinesiol Human Performance Lab Calgary AB Canada

We developed and analyzed an inverse numerical model based on Fick's second law on the dynamics of drug release. In contrast to previous models which required two state descriptions of diffusion for long- and short-term release processes, our model is valid for the entire release process. The proposed model may be used for identifying and reducing experimental errors associated with measurements of diffusion based release kinetics. Knowing the initial and boundary conditions, and assuming Fick's second law to be appropriate, we use the methods of Lagrange multiplier along with least-square algorithms to define a cost function which is discretized using finite difference methods and is optimized so as to minimize errors. Our model can describe diffusion based release kinetics for static and dynamic conditions as accurately as finite element methods, but results are obtained in a fraction of CPU time. Our method can be widely used for drug release procedures and for tissue engineering/repair applications where oxygenation of cells residing within a matrix is important. (C) 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

关键词： Finite element method Finite difference method least square algorithm Continuum model Computational mechanics Numerical scheme Diffusion Release kinetics

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Loss-of-excitation analysis and protection for pumped-storage machines during starting

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IET RENEWABLE POWER GENERATION 2016年第1期10卷 71-78页

作者： Li, Bin Duan, Zhitian Wang, Xin Wu, Jianzhong Tianjin Univ Key Lab Smart Grid Minist Educ Tianjin 300072 Peoples R China Tianjin Elect Power Co Customer Serv Ctr Tianjin 300010 Peoples R China Cardiff Univ Inst Energy Cardiff Sch Engn Cardiff CF24 3AA S Glam Wales

The reversible synchronous machines in a pumped station are put into operation frequently for effective operation of the hydro pumped-storage system. The detection of loss-of-excitation (LOE), which is a common failure for synchronous machines, must be guaranteed not only in normal operation, but also under starting and other possible operation conditions. A model of pumped-storage units under the starting condition was developed using the SimPowerSystems in Matlab/Simulink. The simulation results and real tests of a pumped-storage power plant in northeast China were presented. The LOE characteristics during starting were analysed for the first time. Since the frequency of voltage and current runs up gradually from zero to the rated frequency during starting, conventional LOE protections based on impedance under the rated frequency have to be disabled during starting. For this reason, a novel LOE protection was developed based on the R-L time-domain model and the least-square algorithm. Theoretical analysis and simulation tests demonstrate that the proposed LOE protection method is correct and valid.

关键词： synchronous machines pumped-storage power stations starting time-domain analysis least mean squares methods power system protection pumped storage machine reversible synchronous machine pumped station hydro pumped-storage system loss-of-excitation starting condition SimPowerSystems pumped storage power plant LOE protection R-L time-domain model least square algorithm

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Applying adaptive prediction to sea-water quality measurements

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EXPERT SYSTEMS WITH APPLICATIONS 2009年第3期36卷 6773-6779页

作者： Hatzikos, E. Hatonen, J. Bassiliades, N. Vlahavas, I. Fournou, E. Aristotle Univ Thessaloniki Dept Informat Thessaloniki 54124 Greece Inst Educ Technol Dept Automat Thessaloniki Greece Univ Sheffield Dept Automat Control & Syst Engn Sheffield S10 2TN S Yorkshire England Inst Educ Technol Dept Gen Sci Thessaloniki Greece

This study explores the possibility of using adaptive filters to predict sea-water quality indicators such as water temperature, pH and dissolved oxygen based on measurements produced by an under-water measurement set-up. Two alternative adaptive approaches are tested, namely a projection algorithm and a least squares algorithm. These algorithms were chosen for comparison because they are widely used prediction algorithms. The results indicate that if the measurements remain reasonably stationary, it is possible to make one-day ahead predictions, which perform better than the prediction that the value of a certain quality variable tomorrow is going to be equal to the value today. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： Projection algorithm least square algorithm One-day ahead prediction

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