A Complete Equivalent Circuit Model for Linear Induction Motor Considering Thrust, Vertical and Transversal Forces

Abstract

Since the linear induction motors working with a laterally asymmetric secondary is very common, this paper develops a complete equivalent circuit model considering the asymmetry to predict thrust, vertical and transversal forces. First, this paper proposes an improved equivalent circuit, which is able to consider the single sided linear induction motor (SLIM) operating condition with a laterally asymmetric secondary and an exponential correction factor, which is used to describe the decay due to the asymmetry. Then the correction factors to the circuit components, i.e. extra magnetizing branch, primary leakage inductance and magnetizing current are presented. Four coefficients to calculate the traction characteristic of a LIMs are then computed: attractive and repulsive force coefficient for vertical and lateral forces, respectively. Also, the thrust, vertical and transversal forces are calculated by the corrected equivalent circuit in a range of rated speed is presented. Finally, these calculated results are verified by measurements carried out on a linear motor test rig.