Investigation of Supplied Currents in Tubular Linear Induction Motor

The linear induction motor (LIM) is structurally divided into the flat and the tubular-type. In this paper, we study one kind of tubular linear induction motor which has the primary configuration composed of four pieces of flat-type core. We call this type of motor "the square tubular LIM". The tubular LIM has such a feature that its primary winding is a kind of ring winding, so we can independently supply the primary currents in each slot and hence easily obtain the various winding schemes. Though the square tubular LIM has various merits as stated above, the number of slots is usually limited in conventional applications. In this paper, therefore, we investigate the exciting current scheme with a view to improving primary magneto-motive forces. Firstly we determine the exciting current scheme in unloaded system by using polyphase alternating currents. Secondly we determine another exciting current scheme in loaded system by the hybrid finite element and boundary element method, and the augmented Lagrange multiplier method. Finally we confirm the proposed method by experiment.