On the Design of Single-Sided Linear Induction Motors Using a Nonlinear Optimization Technique

Abstract

Both low-speed wheel-on-rail and medium-speed Maglev transport system with single-sided linear induction motor (SLIM) propulsion have been in the stage for practical application.
This paper presents the method of optimizing the design parameters of SLIM's using nonlinear optimization method. The optimization problem is formulated by use of the design formulas taking into account the end effect, skin effect and air gap leakage, and the transformation method and the simplex method are applied to solve the problem. Seven parameters, such as the number of poles, the pole pitch and the stack height, are chosen as the independent variables. The output KW /input KVA, the maximum flux density in teeth, the temperature raise, the primary length, the stack height and the maximum thrust are selected as the constraint function. The performance characteristics are estimated using space harmonic analysis as well as the approximate equations.
The method is applied to the SLIM design for urban transit, the maximum speed is about 70km/h. As the transformation methods, the interior point transformation and the exterior point transformation are compared from the stand points of accuracy and CPU time. The design is analyzed under the several objective functions, the primary weight, the input KVA and the cost of secondary materials.