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A Power Electrical Signal Tracking Strategy Based on the modulating functions Method

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2009年第10期56卷 4079-4087页

作者： Fedele, Giuseppe Picardi, Ciro Sgro, Domenico Univ Calabria Dept Elect Comp & Syst Sci I-87036 Arcavacata Di Rende Italy

The number of pieces of equipment based on static converters such as uninterrupted power systems, series or shunt compensators, and distributed generation systems is increasing in the actual power distribution systems. For correct operation in grid-connected condition, these equipment need the information about amplitude, phase angle, and frequency of the grid fundamental voltages and currents. Since noise, harmonic pollution, and frequency variations are common problems in the utility grid, then it is necessary to have systems able to extract information about the fundamental values from highly distorted signals. For these reasons, robust and accurate estimation and synchronization methods are necessary to obtain the aforementioned information also in noise environmental. This paper presents a power electrical signal tracking strategy consisting in the combined use of a simple and robust frequency estimation method based on modulating functions and an orthogonal system generator including the second-order generalized integrator. The proposed strategy has the advantages of a fast and accurate signal tracking capability and a good rejection to noise due to the low-pass filter properties of the modulating functions. The effectiveness of the proposed method is validated through comparisons with existing methods performing simulated and laboratory experiments.

关键词： Frequency detection grid synchronization modulating functions phase-locked loop (PLL)

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THE ROLE OF PARAMETER CONSTRAINTS IN EE AND OE METHODS FOR OPTIMAL IDENTIFICATION OF CONTINUOUS LTI MODELS

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INTERNATIONAL JOURNAL OF APPLIED MATHEMATICS AND COMPUTER SCIENCE 2012年第2期22卷 379-388页

作者： Byrski, Witold Byrski, Jedrzej AGH Univ Sci & Technol Dept Automat Control PL-30059 Krakow Poland

The paper presents two methods used for the identification of Continuous-time Linear Time Invariant (CLTI) systems. In both methods the idea of using modulating functions and a convolution filter is exploited. It enables the proper transformation of a differential equation to an algebraic equation with the same parameters. Possible different normalizations of the model are strictly connected with different parameter constraints which have to be assumed for the nontrivial solution of the optimal identification problem. Different parameter constraints result in different quality of identification. A thorough discussion on the role of parameter constraints in the optimality of system identification is included. For time continuous systems, the Equation Error Method (EEM) is compared with the continuous version of the Output Error Method (OEM), which appears as a special sub-case of the EEM.

关键词： continuous systems parameter constraints in identification modulating functions transfer function normalization least squares method

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Design and Implementation of a New Algorithm for Fast Diagnosis of Step Changes in Parameters of Continuous Systems

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IFAC Proceedings Volumes 2012年第20期45卷 695-700页

作者： J. Byrski W. Byrski AGH University of Science and Technology Department of Automatics Al. Mickiewicza 30 30059 Krakow Poland

In this paper special adaptation of modulating functions method MFM for fast detection of step changes in parameters of continuous and linear systems is presented. The modulating functions method is well known for identification of continuous, linear, time-invariant system CLTIS. The characteristic feature of MF method in its application to the problem of identification of step changes in parameters is the existence of fixed time delay in the reconstruction of the new value of parameters after their failure. The aim of this paper is presentation of the substantial modification of MFM which enables optimal identification of parameter faults with minimization of time delay.

关键词： parameter identification modulating functions fault detection linear continuous systems

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The use of modulating functions for identification of continuous systems with time-varying parameters

The use of modulating functions for identification of contin...

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3rd International Conference on Informatics in Control, Automation and Robotics

作者： Byrski, Witold Byrski, Jedrzej AGH Univ Sci & Technol Inst Automat PL-30059 Krakow Poland

ISBN: (纸本)9728865619

In the paper the use of modulating functions for the optimal identification of the structure and parameters of continuous linear systems is presented. The modulating functions with compact support [0, h] are used in convolution filter for transformation of input/output signal derivatives. Based on pre-filtered functions continuous moving window [t-T, t] is used for on-line method for identification is presented - with the use of quadratic constraints on parameters Theta. The numerical results of some examples are shown.

关键词： parameter identification modulating functions linear continuous systems

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Time-varying system identification using modulating functions and spline models with application to bio-processes

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COMPUTERS & CHEMICAL ENGINEERING 2000年第12期24卷 2739-2753页

作者： Ungarala, S Co, TB Cleveland State Univ Dept Chem Engn Cleveland OH 44115 USA Michigan Technol Univ Dept Chem Engn Houghton MI 49931 USA

Time dependent parameters are frequently encountered in many real processes which need to be monitored for process modeling, control and supervision purposes. modulating functions methods are especially suitable for this task because they use the original continuous-time differential equations and avoid differentiation of noisy signals. Among the many versions of the method available, Pearson-Lee method offers a computationally efficient alternative. In this paper, Pearson-Lee method is generalized for non-stationary continuous-time systems and the on-line version is developed. The time dependent parameters are modeled as polynomial splines inside a moving data window and recursion formulae using shifting properties of sinusoids are formulated. The simple matrix update relations considerably reduce the number of computations required when compared with repeatedly using FFT. The method is illustrated for estimating the kinetic rates and yield factors as time-varying parameters in a fermentation process. The Monod law along with temperature dependency models were used to simulate the data. The simulation study shows that it is not necessary to assume a growth model in order to estimate the kinetic rate parameters. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词： parameter estimation modulating functions Pearson-Lee method time-varying systems microbial processes

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Design and Application of Digital FIR Differentiators Using modulating functions

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IFAC Proceedings Volumes 2000年第15期33卷 1037-1042页

作者： Armin Wolfram Olaf Moseler Darmstadt University of Technology Institute of Automatic Control Laboratory for Control Engineering and Process Automation Landgraf-Georg-Strasse 4 D-64283 Darmstadt (Germany) Phone: (+49) 6151 167406 Fax: (+49) 6151 293604

Continuous Process Models are widely used in system identification and fault detection. However, dynamic models require the derivatives of the process' input and output signals. Often they cannot be accessed by measurements. Thus they have to be provided by digital filters. Commonly state variable filters are used for this purpose. But this approach has a couple of drawbacks caused by the recursive structure of the filter. In this paper a consistent approach for the design of FIR differentiators by means of modulating functions is proposed. Finally the application of these filters for fault detection using a microcontroller is presented.

关键词： Finite Impulse Response Filter Differentiators modulating functions System Identification Fault Detection

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Parameter and Derivative Estimation for Nonlinear Continuous-Time System Identification

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IFAC Proceedings Volumes 2001年第6期34卷 663-668页

作者： Marc Niethammer Patrick H. Menold Frank Allgöwer Institut für Systemtheorie technischer Prozesse Universität Stuttgart

In this note we investigate parameter identification for nonlinear continuoustime SISO systems, based on input/output data, where the output is assumed to be noise corrupted. Continuous-time identification requires (i) the estimation of derivatives of the output (which is nontrivial due to the influence of noise), a suitable measure there of or a way to avoid them and (ii) methods for parameter estimation based on the measured data. Problem (i) is addressed by reviewing modulating functions and the concept of delayed state variable filters; furthermore a high-gain observer is introduced as an approach to provide the necessary derivative information. Its performance is investigated with respect to the modulating function and the delayed state variable filter approaches. Least-squares methods are assessed for continuoustime nonlinear identification (problem (ii)). It is shown that parameter identification based on modulating functions and a standard least-squares method does not guarantee bias-free estimates for some systems. Whereas ordinary (or weighted) leastsquares is sufficient for parameter identification by means of modulating functions it is not for the delayed state variable filter and the high-gain observer approaches (due to dependencies between error terms). Requirements on least-squares methods for nonlinear continuous-time system identification are discussed and a solution for bilinear systems is given. The importance of an appropriate least-squares method is underlined by parameter identification for a simulated bilinear example system.

关键词： high-gain observer delayed state variable filter modulating functions least-squares techniques parameter estimation

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Experimental physical parameter estimation of a thyristor driven DC-motor using the HMF-method

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CONTROL ENGINEERING PRACTICE 1998年第5期6卷 615-626页

作者： Daniel-Berhe, S Unbehauen, H Ruhr Univ Bochum Fac Elect Engn Control Engn Lab D-44780 Bochum Germany

This paper deals with the physical parameter estimation of the nonlinear continuous-time dynamics of a thyristor-driven de-motor experimental set-up using the Hartley modulating functions (HMF) method. The approach applies a frequency-weighted least-squares formulation to estimate the nonlinear continuous-time system parameters based on input-output data records over a finite time interval. The laboratory experimental set-up of the plant is facilitated by a computer-aided control system design software system, CADACS. The method has given satisfactory experimental results, and demonstrates its feasibility for use in parameter estimation of physically-based continuous-time systems. Due to its encouraging results, further studies will continue, in order to implement the methodology in the form of batch scheme recursive estimation for nonlinear continuous-time dynamics. (C) 1998 Elsevier Science Ltd. AII rights reserved.

关键词： physical parameter estimation dc motors modulating functions nonlinear continuous-time systems

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Detecting hidden periodicity of time-series generated by nonlinear processes in magneto-plasma

Detecting hidden periodicity of time-series generated by non...

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VIth International Conference on Mathematical Methods in Electromagnetic Theory (MMET 96)

作者： Iavorskyj, I Mykhajlyshyn, V Karpenko Physico-Mechanical Inst of the Natl Acad of Sciences of Ukraine Lviv Ukraine

ISBN: (纸本)9660200269

Questions of applications of models of hidden periodicity in the region of fluctuations and waves in the magnetospheric and space plasma are considered. The signals of geomagnetic pulsations PC-1 caused by hydromagnetic emissions of the magnetospheric plasma and having a kind of wavepackets or beatings have been studied. The given study of fine structure of discrete wavepacket geomagnetic pulsations PC-1 has allowed to reveal a number of earlier unknown features of signals. The estimations of modulating functions are obtained. Methods of their parametrization are considered. The wavepackets, forming processes, are shown to be synchronized. The global source of such synchronism is connected with natural resonances of the magnetospheric cavity.

关键词： wavepacket geomagnetic pulsations fine structure random processes modulating functions

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POISSON WAVELETS APPLIED TO MODEL IDENTIFICATION

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JOURNAL OF PROCESS CONTROL 1995年第4期5卷 225-234页

作者： KOSANOVICH, KA MOSER, AR PIOVOSO, MJ DUPONT CO INC CENT RES & DEVEXPTL STNWILMINGTONDE 19880 UNIV S CAROLINA SWEARINGTON ENGN CTRDEPT CHEM ENGNCOLUMBIASC 29208

A novel wavelet transform is introduced based on the backward difference of the Poisson probability density function. This family of wavelets is a function of one discrete and two continuous variables. The Poisson wavelet transform is useful for system identification, parameter estimation and model validation. In particular, it is well-suited for linear time-invariant systems that are modelled as combinations of decaying exponentials with a single time delay. A fast computational algorithm for computing the Poisson wavelet transform is developed using cascaded first-order filters. The concepts are demonstrated on a three-tank process and a simplified heat exchanger.

关键词： INTEGRAL TRANSFORMS modulating functions PARAMETER ESTIMATION

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