Impact of Manufacturing Stresses On Multiple-Rib Synchronous Reluctance Motor Performance

Abstract

The effects of manufacturing stresses on the overall magnetic properties of electrical steel core applied in the stator and transversally-laminated rotor of Synchronous Reluctance motors are studied. In addition, it is investigated how the -manufacturing-degraded electrical steel core affects the electromagnetic performance of two different Synchronous Reluctance motors. The traditional transversally-laminated rotor of this kind of a machine requires the adoption of mechanical elements (inner and tangential ribs) to maintain its mechanical integrity. Especially, for high-speed applications, the number of rotor ribs must be increased to make the rotor withstand higher centrifugal forces. Lamination manufacturing typically affects the magnetic properties of electrical steel by reducing its permeability at the machined edge. This machining effect is greater when the overall core layer area surrounded by the machined edges is small i.e., the machined surface area ratio to the total core area is high. Considering this, the degradation of the core magnetic properties in the ribs could improve the performance of the machine, and this effect would be more visible when the machine is designed with a higher number of narrow ribs with the adoption of Topology Optimization. The paper aims to propose some guidelines for the simulation of these effects starting from the measurements on defined core samples and then based on the measured results the simulation model should be updated accordingly. The samples are manufactured from several assembled sheets in order to modify the width of the cut area while maintaining the same external geometry.