Performance Analysis of a Novel Triple-Permanent-Magnet-Excited Magnetic Gear and Its Design Method

This paper proposes a novel triple-permanent-magnet-excited (TPME) magnetic gear (MG) with an extra stationary layer of permanent magnets (PMs) sandwiched between adjacent ferromagnetic segments to produce an additional torque and in which a simplified consequent-pole Halback array-type PM arrangement is employed to improve the magnetic field characteristic. The novel TPME-MG has a higher torque transmission density when compared with its conventional counterpart. Its design method using the numerical finite-element method and the optimization algorithm is presented. The novel TPME-MG with optimal PM arrangement can significantly achieve higher torque density and torque per PM volume. The results of finite-element computation show that the proposed TPME-MG with optimal PM arrangement has over 74% higher torque density (torque per unit overall volume) and more than 37% higher torque per PM volume compared with a conventional surface-mounted MG, and can reach 51% higher torque density and 34% higher torque per PM volume compared with an original design of TPME-MG, which validates the effectiveness of the design method for the PM arrangement in the novel TPME-MG.