A High-Torque-Density Variable-Flux Memory Machine Utilizing Novel (Ce, Nd)-Fe-B Magnets

Variable-flux memory machines (VFMMs) are considered as promising candidate in adjustable speed drive applications. However, the exploration of VFMMs with acceptable magnetization state (MS) regulating current and high-torque density is still a challenging issue. This article presents a high-torque-density VFMM which is comparable with conventional permanent-magnet machines. The newly developed (Ce, Nd)-Fe-B magnet with remarkable characteristics is employed in the investigated VFMM. The characteristics of the (Ce, Nd)-Fe-B magnet are firstly introduced. Second, a simple and superior VFMM topology with (Ce, Nd)-Fe-B magnet is evaluated in terms of torque production capability, MS regulation characteristics, and overall efficiency and compared with the benchmark machine.