Comparative study of permanent-magnet synchronous machines with concentrated windings for railway application

The paper presents a comparative study of 3-phase permanent-magnet (PM) synchronous machines (PMSM) with concentrated windings. The purpose of this study is to find a machine giving the better electromagnetic performance (torque, losses, back electromotive force...) for railway traction. Three PMSM with concentrated windings having identical output power, stator and rotor outer diameter, air-gap, axial length,..., are designed. Two machines have equal tooth widths, with one having a coil wound on every tooth and the other having a coil wound on alternate teeth, while the third machine has also coils wound on alternate teeth but these are wider than the unwound teeth. A comparison of the performances for single layer and double layer concentrated windings is made using finite element analysis.