作者:
Marshall, D.A.Venter, F.P.van Wyk, J.D.Dr. Dirk Adriaan Marshall (1960) is an Industrial Research fellow with the Energy Laboratory at the Rand Afrikaans University
Johannesburg/RSA. He is employed by Eskom (National Electric Company RSA) in the Transmission Engineering Division where his corporate responsibility includes high voltage direct current transmission and voltage quality. He obtained the 8. Eng. M. Eng. and D. Eng degrees in 1983 1985 and 1990 respectively from the Rand Afrikaans University. He was co-recipient of one IEEE Prize Paper Award. (Transmission Engineering Division Megawattpark P.O. Box 1091 Johannesburg 2000 Republic of South Africa T +2711/800-3250 Fax +27 11/800-2779) Frederik Petrus Venter (1966) received the B. Eng. and hit. Eng. degrees from the Rand Afrikaans University Johannesburg/RSA
in 1989 and 1991 respectively. He has at present submitted a Thesis for the D. Eng. degree at the same University. His field of interest includes power electronic applications in high voltage networks and Active Power Filtering. He was co-recipient of one IEEE Prize Paper Award. (Rand Afrikaans University Laboratory for Energy P.O. Box 524 Johannesburg 2000. Republic of South Africa T + 2711/489-2454 Fax + 2711/489-2466) Dr. Jacobus Daniel Van Wyk (1939) received the M. Sc. Eng. degree from the University of Pretona/RSA
and the degree of Doctorate of Technical Science from the University of Technology Eindhovenmhe Netherlands in 1966 and 1969. He has worked with the S.A. Iron and Steel Corporation. the University of Pretoria and was on the technical and scientific staff of the University in Eindhoven. between 1961 and 1972. From 1971 to the present he has been a Full Professor of Electrical and Electronic Engineering at the Rand Afrikaans University Johannesburg/RSA at present holding a chair in Power Electronics and has been involved in extensive industrial work. He is at present Programme Director of the Electronic Power Control Research Group in the Energy Laboratory of the Faculty of Engineering. Since 1976 he
The development of theoretical techniques for the instantaneous calculation of load current components is evaluated. The associated instantaneous calculation of load power components is also evaluated since it is used...
New type of predictive controllers for saturating systems is described. It relies on an analytical approximation of the controlled process by the I 2 -model. The closed-loop behavior may be prescribed by means of refe...
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New type of predictive controllers for saturating systems is described. It relies on an analytical approximation of the controlled process by the I 2 -model. The closed-loop behavior may be prescribed by means of reference trajectories defined as optimal braking trajectories of the actual model as well as by choosing a time horizon for matching with these trajectories. The method essentially improves features of classical relay minimum time systems. It enables to modify their behavior in a similar way as using the pole assignment method and so to achieve a desired degree of robustness against structural and state perturbation. Taking into account saturation limits and parasitic time lags makes the task of tuning controller transparent and reliable which is illustrated by the example of positional servo control
The method for adjustment of fuzzy controller parameters is presented. In fuzzy control to he control signal s are generated by an appropriate inference mechanism from the linguistically expressedrule base. To refine ...
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The method for adjustment of fuzzy controller parameters is presented. In fuzzy control to he control signal s are generated by an appropriate inference mechanism from the linguistically expressedrule base. To refine the parameters of the rules it is necessary to have either a thorough insight into the dynamics of the overall system or to develop an appropriate adaptation mechanism. Such mechanism with Kohonen neural network like structure is presented and documented on the example of motion control system.
The fuzzy logic controller for the velocity d.c. servo system was designed. It was shown, that the system can successfully deal with the nonstationary moment of inertia and load torque and with the influence of flexib...
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The fuzzy logic controller for the velocity d.c. servo system was designed. It was shown, that the system can successfully deal with the nonstationary moment of inertia and load torque and with the influence of flexible gearbox. The practical concept of implementation using the unique transfer function and a look-up-table of coefficients was introduced. Such method is simple and has low computational requirements.
Robustness properties of non-companion representation of linear systems, studied using a criterion due to contribution of Drcuzenouic 1969, are retained to a limited extent only. Hajor drawback of this approach, utili...
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Robustness properties of non-companion representation of linear systems, studied using a criterion due to contribution of Drcuzenouic 1969, are retained to a limited extent only. Hajor drawback of this approach, utilizing the facilitating fact of B(CB)^C being a projector such that disturbances or parameter variations belong to the range space of input matrix B, is that the extent of the robustness is not determined. In this paper, quantitative measures are introduced for assessing the extent of lack of robustness. Method is based on singular value analysis of closed-loop state matrix F in sliding mode introducing the simple stability criteria.
The innovating impact of modern information technologies in computer based systems control is causing conceptual changes in energy control and management systems. Variable-structure control strategies can be introduce...
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The innovating impact of modern information technologies in computer based systems control is causing conceptual changes in energy control and management systems. Variable-structure control strategies can be introduced into such systems in several ways. The use of symmetric VS controls enables handling the uncertainty in systems models. The superiority of VS control over continuous control is demonstrated using a representative case study
Dynamic modeling of the ankle joint is performed by means of the non-parameteric Wiener-Volterra approach. The original version is extended so that colored noise inputs can be handled. This is imposed from reality, i....
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Dynamic modeling of the ankle joint is performed by means of the non-parameteric Wiener-Volterra approach. The original version is extended so that colored noise inputs can be handled. This is imposed from reality, i.e., all movements of the angle joint must be limited in frequency as well as in amplitude. Experiences related to the method are briefly summarized and supported with results obtained on a normal subject.< >
Quite a number of protective snubbing cicuits have been proposed in the technical literature in the past. Few, or none of these have been compared to one another, making it difficult for the designer to find the one m...
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Quite a number of protective snubbing cicuits have been proposed in the technical literature in the past. Few, or none of these have been compared to one another, making it difficult for the designer to find the one most suitable for a specific application. As opposed to commutation circuits for thyristor-based inverters, a method for objectively comparing various snubber circuits for voltage source inverters, has not yet been proposed. In this article such a method is proposed and three well known snubber circuits, which have been applied in practice, are compared objectively. From the results obtained, it is clear that some snubber circuits have better overall performance than others.
A new set of criteria to compare rival converter topologies on a scientific basis are introduced. Power transmission effectivity of components is addressed which compares the power handling capability of components ag...
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A new set of criteria to compare rival converter topologies on a scientific basis are introduced. Power transmission effectivity of components is addressed which compares the power handling capability of components against the active power delivered by the converter. This method of rating is then applied to some single switch topologies as used in induction heating, involving a detailed modelling which includes time domain simulation, analytical modelling and experimental verification.
作者:
R. BarsR. HaberDepartment of Automation
Technical University of Budapest Goldmann Gy. tér 3 Budapest Hungary Fachhochschule Köln
Faculty of Plant and Process Engineering Köln FRG and Ruhr-University Faculty of Mechanical Engineering Department of Control Systems Bochum FRG
The unknown nonlinear process is approximated by the Hammerstein model, which is one of the natural expansions of the discrete convolution model to nonlinear systems· Because of the large number of the parameters...
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The unknown nonlinear process is approximated by the Hammerstein model, which is one of the natural expansions of the discrete convolution model to nonlinear systems· Because of the large number of the parameters an identification procedure with scalar convergence coefficients is recommended. The control task is to follow a reference model output predicted ahead in a given horizon· The present and future control activities during the prediction horizon are determined minimizing a functional of the error signal between the predicted values of the reference model and the system output. The control signal is assumed constant during the control horizon and the calculation is repeated in each control interval. Simulation results represent the robust behaviour of the control algorithms.
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