Optimal design of a linear induction motor applied in transportation

Several optimal design schemes of a single-sided linear induction motor (SLIM) adopted in linear metro are presented in this paper. Firstly, the equivalent circuit of SLIM fully considering the end effects, half-filled slots, back-iron saturation and skin effect is proposed, based on one-dimensional air-gap magnetic equations. In the circuit, several coefficients including longitudinal end effect coefficients K_r(s) and K_x(s), transversal end edge effect coefficients C_r(s) and Cx(s), and skin effect coefficient K_f are achieved by using the dummy electric potential method and complex power equivalence between primary and secondary sides. Furthermore, several optimal design restraint equations of SLIM are provided in order to improve the operational efficiency and reduce the primary weight. These nonlinear equations are solved by using genetic algorithm and mixture penalty function method. The optimal schemes are compared with the original design of one company, where analysis on parameters is made in detail. These results show that the optimal schemes are reasonable for improving the performance of SLIM.