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Investigating the protection system of electric motors based on its main working parameters

Manafov Elshan, Isgandarov Islam, Huseynov Farid

Zeszyty Naukowe. Transport / Politechnika Śląska

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2022

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z. 115

63--74

EN

This research was devoted to the creation of a protection system for electric motors used in industry and transport, based on modern and traditional sensors. In the course of operation, the malfunctions of electric motors have been investigated and it was found that the accident modes occur mainly due to exceeding the permissible values of the current, voltage and temperature parameters. Modern sensors of current, voltage, and temperature have been compared and the most effective ones were selected for use in electric motors. Based on reasoning from these sensors, a protection system for a low-power electric motor has been developed in the laboratory. In addition, in the Multisim application software package, a simulation of the operation of the protection system at different voltage and current values was performed, and a circuit of the sensor control unit and the power source for powering the protection system was constructed. It has been proposed to apply such a multi-parametric complex protection system for electric motors, especially in transport.

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Optimality properties of controls with bang-bang components in problems with semilinear state equation

Felgenhauer U.

Control and Cybernetics

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2005

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Vol. 34, no 3

763-785

EN

In this paper we study optimal control problems with bang-bang solution behavior for a special class of semilinear dynamics. Generalizing a former result for linear systems, optimlity conditions are derived by a duality based approach. The results apply for scalar as well as for vector control functions and, in particular, for the case of the so-called multiple switches, too. Further, an iterative procedure for determining switching points is proposed, and convergence results are provided.

3

Equivalence of second order optimality conditions for bang-bang control problems. Part 1: Main results

Osmolovskii N. P., Maurer H.

Control and Cybernetics

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2005

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Vol. 34, no 3

927-950

EN

Second order optimality conditions have been derived in the literature in two different forms. Osmolovskii (1988a, 1995, 2000, 2004) obtained second order necessary and sufficient conditions requiring that, a certain quadratic form be positive (semi)-definite on a critical cone. Agrachev, Stefani, Zezza (2002) first, reduced the bang-bang control problem to finite-dimensional optimization and then show that well-known sufficient optimality conditions for this optimization problem supplemented by the strict bang-bang property furnish sufficient conditions for the bang-bang control problem. In this paper, we establish the equivalence of both forms of sufficient conditions and give explicit relations between corresponding Lagrange multipliers and elements of critical cones. Part 1 summarizes the main results while detailed proofs will be given in Part 2.

4

Second order optimality conditions for bang-bang control problems

Maurer H., Osmolovskii N. P.

Control and Cybernetics

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2003

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Vol. 32, no 3

555-584

EN

Second order necessary and sufficient optimality conditions for bang-bang control problems have been studied in Milyutin, Osmolovskii (1998). These conditions amount to testing the positive (semi-)definiteness of a quadratic form on a critical cone. The assumptions are appropriate for numerical verification only in some special cases. In this paper, we study various transformations of the quadratic form and the critical cone which will be tailored to different types of control problems in practice. In particular, by means of a solution to a linear matrix differential equation, the quadratic form can be converted to perfect squares. We demonstrate by three practical examples that the conditions obtained can be verified numerically.

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Lqr-Based Nonlinear Tuning Relay Control Design With Fast Convergence

Yu X., Xia Y., Ledwich G., Oghanna W.

International Journal of Applied Mathematics and Computer Science

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1999

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Vol. 9, no 2

313-326

EN

In this article, we present a relay control scheme based on LQR design with fast convergence. This scheme provides a practical and simple way to achieve fast convergence based on the well-known LQR design principle. The controller is a global stabiliser in the sense that for any given initial condition, we can always initialize the controller to drive the system to reach the origin. This controller is tunable in accordance with the position of the system state: the closer to the origin, the larger the control gains, which results in a fast control that maintains bounded control magnitude. It has also been shown that setting matrix Q can significantly influence the tendency of eigenvalues to switch the hyperplane. The relation between matrix Q and the tendency of those eigenvalues has been identified. Simulation results are presented to demonstrate the effectiveness of the scheme.