Improving Saliency of High-Speed Synchronous Reluctance Machine Using Rotor Sleeve made of Bi-State Magnetic Material

Synchronous reluctance (SynRel) machines with improved saliency ratio can be realized using bi-state magnetic material (BSMM) in the rotor. However, a significantly higher number of localized heat treatments are required on the BSMM to maximize its effectiveness on being used in the conventional SynRel rotor structure. The cumbersome manufacturing process and its associated cost renders the conventional SynRel rotor topology as an impracticable solution for exploiting the benefits of BSMM. Therefore, it is essential to identify alternate SynRel rotor structures which can effectively utilize the advantages of BSMM with reduced manufacturing related complexity. Consequently, a 3 kW, 90 krpm high-speed sleeve rotor SynRel machine having a retaining sleeve of BSMM is analysed in this paper. The proposed rotor structure offers 26% more torque with a reduced manufacturing related complexity compared to conventional SynRel rotor with BSMM. Further, 3D simulations are performed to understand the impact of eddy current on the electromagnetic performance of sleeve rotor SynRel machine with BSMM sleeve.