SPECIAL CONSIDERATIONS FOR THE MATHEMATICAL MODELING AND CONTROL OF THE MULTISECTIONAL ASYNCHROOUS MOTOR

Abstract

In various branches of industry and transport there exists the necessity of the direct realization of the progressive motion of the executive elements of the working machines. For this purpose, it is expedient to apply linear induction motors (LIM), main advantages of these motors are high reliability, simple construction, reduction of the dimensions, mass and cost of the installation as well as the possibility to obtain progressive motion with the unlimited values of acceleration rate and deceleration without any mechanical transmission. However, LIM are characterized by a number of the characteristic features, which must be taken into account in the process of the development and  implementation, namely: increased  working air gap and, as a result, increased dissipation flows, saturation and magnetic circuit discontinuity, that lead to the emergence of the longitudinal end effects, decrease of efficiency and power factor. Aim of the research is the analysis of the impact of the peculiarities of LIM constructive realization on its static and dynamic characteristics.

Main attention is paid to LIM with the limited length of the inductor or rotor, which can remain in the state when primary and secondary elements interact only partially, i. e., do not have complete overlapping of each other. The base of the specified LIM model is standard model of the rotational induction electric motor of Matlab/Simulink package, using the modified Т-shaped equivalent circuits t of LIM, which takes into account transverse and longitudinal edge and end effects as well incomplete overlapping of the inductor.

As a result of research, carried out, it is shown that the incomplete overlapping of the inductor influences both the starting process and steady-state motion of LIM and worsens the transient processes quality, decreases  the traction effort and acceleration.

The paper also considers the characteristic features of LIM with multisectional inductor control in starting, steady-state and braking modes.

The results of the performed research enable to formulate the recommendations, regarding the optimization of the construction and improvement of the methods of LIM control.