Methods for controlling a linear asynchronous motor

Abstract

This article describes the case of one of possible method of controlling a linear asynchronous motor (LAM) with a controlled normal component of the force of interaction between an inductor and a reactive bus. It is shown that the normal force in a unilateral linear asynchronous motor can affect significantly the operation of devices and systems on which a motor is installed. This normal force can attract an inductor to a reactive bus or repel it from a reactive bus. For the model of a motor, which is represented by four zones, namely, an inductor, an air gap, a conductive bus, and a steel core of a reactive bus, the analytical expressions for the calculation of the components of a magnetic field in an air gap were obtained. The effect of the longitudinal and transverse edge effects in the considered plane model of a motor is not considered. The expressions for the determination of the specific tangential and normal forces per area unit were found. It is shown that, under a change in the slide from negative to positive values, the tangential force changes similarly to the electromagnetic torque of a conventional asynchronous motor with a rotating rotor. Under a change in the slide, the normal force can attract an inductor to a reactive bus or repel it from a reactive bus. The force of attraction reaches the highest values under a zero slide. The slide under which the normal force is equal to zero is determined only by the pole pitch and the conductivity of material of a reactive bus and provides the operation of a motor at the highest power factor. It is proposed to use the measured normal force value as a parameter for the construction of a traction linear asynchronous motor-control system.