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In this paper, a nonlinear modeling and control method for magnetic bearings is designed, considering the core material nonlinear high flux behavior for the first time. A combination of the generalized Lur'e method and linear matrix inequalities is used during the modeling and control design process. It is common to include a margin of safety in amplifiers and other active magnetic bearing (AMB) components. The nonlinear modeling makes it possible to operate an existing industrial AMB system with larger electric currents and thus achieve a larger maximum load capacity than existing AMB modeling and control practices allow. As a result, existing industrial AMB's can be tuned to become more resilient in dealing with external disturbances. In addition, smaller and lighter AMBs can be designed by using the proposed method, which enables achievement of the same maximum force requirement of present-day larger AMB systems. [ABSTRACT FROM AUTHOR]

This paper mainly investigates admissibility and D-admissibility for discrete singular systems with uncertainties existing in the difference matrix E and the system matrix simultaneously. An equivalent D-admissible condition for the nominal system is originally derived. By involving the uncertainties in both the difference and the system matrices, we devote to analyse the robust admissibility and the robust D-admissibility for the regarded uncertain system. Since the derived criteria are all expressed in terms of strict linear matrix inequalities (LMIs), we thus can handily verify them via current LMI solvers. Finally, illustrative examples are given to demonstrate the effectiveness and validity of the proposed approach. [ABSTRACT FROM PUBLISHER]

In order to conveniently analyze the stability of various discrete-time recurrent neural networks (RNNs), including bidirectional associative memory, Hopfield, cellular neural network, Cohen-Grossberg neural network, and recurrent multiplayer perceptrons, etc., the novel neural network model, named standard neural network model (SNNM) is advanced to describe this class of discrete-time RNNs. The SNNM is the interconnection of a linear dynamic system and a bounded static nonlinear operator. By combining Lyapunov functional with S-Procedure, some useful criteria of global asymptotic stability for the discrete-time SNNMs are derived, whose conditions are formulated as linear matrix inequalities. Most delayed (or non-delayed) RNNs can be transformed into the SNNMs to be stability analyzed in a unified way. Some application examples of the SNNMs to the stability analysis of the discrete-time RNNs shows that the SNNMs make the stability conditions of the RNNs easily verified. [ABSTRACT FROM AUTHOR]

This paper addresses the design problem of static output feedback controllers for nonlinear interval time-delay systems represented by the Takagi–Sugeno fuzzy model. Departing from traditional approaches, which are to find a common positive definite matrix for all rules, sufficient conditions to guarantee the robust stability for such fuzzy systems are derived in term of matrix measures of system matrices in the consequent parts of fuzzy rules. These conditions are further transformed into linear matrix inequalities. By solving linear matrix inequalities, a static output feedback controller that can stabilize the considered uncertain time-delay system can easily be obtained. Finally, an example is provided to illustrate the effectiveness of our approach. [Copyright &y& Elsevier]

In the field of protective relay, a dream which is unable to be realized by analogue technology has come true with the advance of computer technology. However, there is still room for the development of a high functional protective system, which makes the most of a merit of digital processing because the present digital relay uses the same principle m an analogous one. The points of proposed theory are that first it uses a lot of data of fault, second uses the first and second Kirchoff laws at the same time which are the starting point of electric circuit theory, and third calculates both fault location and resistance by solving nonlinear simultaneous equations, In this paper high speed calculation for protective relays is achieved by solving a com act matrix using the Newton-Raphson method. matrix consists of two sore of variables (fault location, fault resistance), end the nonlinear simultaneous equation is reduced by definition of new variables. As a result of a plying this theory to some real faults, we testified that the fault location error was within 0.1 percent, and the calculation time was less than 5 ms. Therefore we think that this theory has already been in a practical stage. The ultimate goal of this theory is the integration of various algorithms of protective relay, fault locator, and fault restoration operation. [ABSTRACT FROM AUTHOR]