Analysis of damper winding designs for direct-on-line synchronous reluctance motor

One of the essential parts of a Synchronous Reluctance Motor (SynRM) for direct-on-line (DOL) applications is a damper winding (DW) which makes the start of the motor possible. However, the DW can also be a considerable source of Joule losses caused by DW currents reacting on the stator current linkage and permeance harmonics. In order to get a comprehension of how DW bars' distribution influences the amount of induced rotor Joule losses at steady state different designs of DW of a SynRM are considered in the paper. Also the authors consider different methods of minimising stator current linkage distortion and permeance harmonics by stator part modification: magnetic wedges, reduction of slot opening and short pitching. A comparison with an induction motor with the same stator was done as well.