Papers by Author: Edvardas Matkevicius

Abstract: The submitted list of scientific publications and literature indicate, that so far there have never been comprehensively analysed the braking modes of the Linear Induction Motor (LIM) with a short secondary part. The article deals with the theoretical simulation model of such a LIM, containing even, odd or fractional number of the active (excitation) zones. The spectral analysis method is used to calculate the spectral characteristics of the motor braking. After having applied, Fourier and Laplace integral transformations for the non – periodic volumetric density functions of the braking current, there have been derived the analytical expressions of the continuous amplitude spectra. These obtained expressions successfully meet/harmonize the analysis of spectral characteristics of the primary and secondary magnetic field.

Abstract: The purpose of the wok is to derive analytical expressions of spectral characteristics at electrical braking of linear induction motor with diverse number of poles as well as to provide results of calculations. The major task in the analysis of braking modes is to determine spectral characteristics of braking current, primary magnetic field and braking force. To this aim Maxwell equations were solved together with Fourier and Laplace integral transformations. The obtained results indicate that in addition to the main component of the magnetic field, when the space frequency is , in the process of braking there appears continuous spectrum of elementary components with the frequencies occupying the infinite sector from - to + . Due to that fact, during the process of energy conversion at the moment of braking, there participate positive – sequence, negative – sequence components and elementary components of the continuous spectrum, motionless in the space.

Abstract: The most important scientific theoretical research works of the linear induction motor (LIM) are made having in mind double – sided symmetric model with the uniform secondary element. Its operation is investigated by already well-known methods used for the rotor asynchronous machines and as a rule with the opposite value of the magnetic poles of the inductors (NS). Authors give the results of the research only of LIM (the scientific aspect of the problem is not well studied yet, it is little known about the ways of the speed and development regulation of the LIM force, by changing the location of the magnetic poles of the inductors (the inductors position between each other) from opposite (NS) to the same (NN) magnetic poles value which is the change of the phase of the inductor current from α = 0 till α = π. By theoretical methods were studied only the LIM features and possibilities their natural speed and the way of the force regulation, which could be used in the mechatronics systems.

Abstract: The paper considers some problems of calculating spectral characteristics of magnetic field of the linear induction motor (LIM), operating at the electrical braking modes. In automatic drives with LIM the electric braking modes are usually applied: dynamic, recuperation, single – phase, capacitor type, braking by means of opposite connection, by pulsating current and inverter type (frequency) braking. During the process of braking in the moving part of the LIM and in some cases in an inductor there are initiated complicated interrelated electromagnetic and electromechanical non – stationary processes. The braking processes have been analysed in the motionless right – sided Descartes system of coordinates x, y, z. There have been presented the expressions of volumetric density of braking current which have been regarded the non – periodic functions of coordinate x. Besides that in cases of single – phase and capacitor braking these expressions are also regarded as the non – periodic functions of time. Therefore when compiling the mathematical model there have been applied Laplace and Fourier integral transformations. After having applied Fourier transformation there have been received the expressions of the spectra amplitudes of primary magnetic field at the dynamic braking under the condition that the number of excited zones in the inductor is even, uneven and fractional. The continuous spectra of amplitudes have been calculated by the software Mathcad 2001 Profesional.

Abstract: The paper considers some problems of calculating major parameters and characteristics of a mechatronic system with a linear induction motor (LIM). It has been shown that LIM operating in the presence of traveling magnetic fields are widely used alongside other actuators. These motors allow for modular design because inductors may be made as independent modules. Then, by choosing the required number of inductors and their arrangement in a mechatronic system, a desired trajectory of transverse motion may be obtained. A theoretical model for LIM calculation, taking into account major assumptions about onedimensional magnetic field, is offered. Complex amplitude is expressed as the exponential function of a longitudinal coordinate of current volumetric density of the inductor. The above inductances as the parameters of dynamic equations may be used in further investigation of dynamics of mechatronic systems. However, in order to create optimal control systems for mechatronic systems with linear actuators, the major parameters and characteristics of a linear motor should be known. Therefore, the present investigation is aimed at developing methods for calculating the parameters of mechatronic systems with linear electric drives.