Calculation of linear induction motor features by detailed equivalent circuit method taking into account non-linear electromagnetic and thermal properties

Abstract

The main purpose of the work is to suggest the technique of solving multi-physics problems (calculation of magnetic, temperature and velocity fields) for the purpose of units with forced cooling system and complex shapes. The general problem is the presence of narrow region in which it is necessary to calculate the velocity field of a cooling liquid. The problem is solved by a simplified method based on a detailed equivalent circuit, which significantly reduces required computational resources in comparison with numerical methods (finite element and finite volume methods). The paper presents the transition from partial differential equations to algebraic equations, created on the basis of detailed equivalent circuits. The results of the model are analyzed on a real linear induction motor applied in the transport system. Thermal modes are being considered depending on cooling intensity and magnitude of power supply parameters of the motor. It is proposed to reduce the computation time by simplified calculation of the velocity field using an analytical coefficient obtained from the analysis of the equivalent circuits. The vectorization of cycles intended for building the stiffness matrix, storage of the matrix in sparse form, and rational sequences of matrix calculations in the course of the solution made it possible to reduce the computational time almost twice as well. The comparison of the accuracy of the results obtained is presented, depending on the discretization of the computational domain and chosen type of interpolation. Verification results of electromagnetic and thermal calculations obtained from experimental data are also presented. © 2019 Elsevier Ltd