Rotor design optimization of synchronous machine with two-part rotor

To achieve saliency ratio and material utilization ratio as high as possible, the main design criteria of a synchronous machine with a two-part rotor, an axially laminated anisotropic (ALA) reluctance part and a surface permanent magnet (SPM) part axially-separated on the same shaft, are explored on the basis of magnetic field analysis including consideration of the saturation effects by FEM. Numerical results show that an optimal design can be obtained, with a larger ratio of pole pitch to air-gap (>400), a proper thickness ratio of insulation layer to iron sheet (0.5-1.0) and a proper laminated pole span (120-140°) in ALA part, and with a higher ratio of magnet height to air-gap (20-30), a proper permanent magnet pole span (130-150°) and a shorter longitudinal length in SPM part