Thrust Control of Linear Induction Motor by Detection of Magnetic Field

Abstract

The linear induction motor is expected to be useful for the industry, the transportation and so on, because of its simple structure and easy maintenance. The thrust control of the motor, however, usually has been an average thrust control, which is not suitable for the position control.
In this paper, we first describe a formulation of a hybrid finite element and boundary element method. The hybrid method is a powerful analysis approach for both non-homogenous and open boundary problems.
Using the two-dimensional hybrid method, we analyze the response of the thrust in the linear motor system by the vector control, in which the air gap flux is adopted as the input signal. In this system, we propose a novel control scheme: the supply current is controlled to have a current vector leading the flux vector by 45 degree, without any electric circuit analysis as in the usual vector control scheme.
Lastly we find it powerful for the instantaneous thrust control to use the constant control for the advanced current angle, by both the analysis and the experiment.