Optimal Designs and Comparison of the Doubly Salient Permanent Magnet Machine and Flux-reversal Machine in Low-speed Applications

The subject of this article is to optimize the design and to compare the performances of a low-speed doubly salient permanent magnet machine with those of a low-speed flux-reversal machine devoted to direct drive applications. The optimization, focused on the maximization of the machines mass-to-torque ratio, is done by a genetic algorithm combined with the finite-element method (FEM). The electromagnetic characteristics of the two optimized machines, including phase flux linkage, inductances, back-electromotive forces (EMFs), and static torque, obtained from FEM analysis, are then analyzed and compared. Finally, the torque cost and the torque density of the two machines are compared with those of other topologies.