Design and Performance Analysis of a New Synchronous Reluctance Machine with Hybrid Cores

As no permanent magnet (PM) material is required and only silicon sheets are needed on the rotor core, the synchronous reluctance machine (SynRM) has received tremendous research attention in the past and it can be used for many driving applications. However, compared with the electrical machine with PM excitation, its torque density, efficiency, and power factor are both low. In this paper, a novel SynRM with hybrid cores (Hybrid-SynRM) is proposed. Specifically, its rotor core is made by the combination of non-grain-oriented (NGO) silicon sheet cores and grain-oriented (GO) silicon sheet cores. The magnetic circuit characteristic of the proposed Hybrid-SynRM is improved by taking the super high magnetization characteristic of the GO silicon sheet along its rolling direction. To verify the performance of the proposed SynRM, the traditional SynRM with NGO silicon sheet cores (NGO-SynRM) is determined as the benchmark machine. For obtaining fair comparison results, both these two machines are optimized under the same conditions. Through the comparison, it can be seen that the torque ability, efficiency, and power factor can be improved greatly by employing the GO silicon sheet block in the SynRM. Therefore, the Hybrid-SynRM can output better performance than the NGO-SynRM especially when the applied electrical loading is high.