Steady and dynamic performance analyses of a linear induction machine

This paper based on the winding function algorithm presents an improved equivalent circuit to analyze single linear induction motors (SLIMs) applied in the linear metro. The circuit deduced from the air-gap magnetic flux density equations can analyze steady and transient performances considering end effects, half filled slots, saturated iron and skin effect. Firstly several stable cases like constant thrust/power region, constant current constant frequency or variable frequencies, constant voltage constant frequency or variable frequencies are presented in detail. Then, maximal thrust at a given speed is optimized by modifying the optimal slip frequency. Finally, transient characteristics of SLIM under constant current constant frequency are investigated. The results indicate that winding function method is one effective way to study SLIM, especially its end effects. It can be used in the electromagnetic design and performance investigation for SLIM combining relative control schemes.