Electromagnetic–Mechanical Design of Synchronous Reluctance Rotors With Fine Features

This paper explores the tradeoff between the electromagnetic and mechanical performances with regard to the design of a synchronous reluctance machine rotor with fine features in the lamination profile-the analyzed machine consists of four rotor poles and its stator is equipped with single tooth coils. The change in the electromagnetic characteristics of the d- and q-axis reactances is explored for variation in radial and tangential rib widths and the impact of increased rib width on the saliency ratio of the machine. It is shown that the increased radial and tangential rib widths impair electromagnetic performance, with the tangential rib having the most pronounced effect on performance in this rotor design. The mechanical performance of the design is also explored in a similar manner, where it is shown that the high stress concentration in the rotor radial and tangential ribs limits the maximum speed of the machine in the field weakening region. The radial rib is found to have the dominant impact on supporting the flux guides. It is shown that the prototyped machine can achieve good electromagnetic performance while maintaining mechanical integrity up to a 25% overspeed of 10000 r/min with features as small as 0.3 mm. Additionally, the challenges associated with manufacturing, selecting a higher rotor pole number, and the possibility of mechanical failure are also discussed in the context of electromagnetic-mechanical design of such rotors, with important avenues of further research suggested.