Torque Analysis of Concentric Magnetic Gear With Interconnected Flux Modulators

In a concentric magnetic gear, the space harmonic fields at inner/outer air gap have equal number of poles and rotate synchronously with the inner/outer permanent magnets, thanks to the flux modulators. The shape of flux modulators is one of the key factors that affect the harmonic fields, and hence the torque capability and ripples. Conventionally, the flux modulators are assembled by stacking small separated pieces of steel laminations; however, it is not easy to hold those small laminations firmly together. In order to make the flux modulators less complicated and more reliable, interconnected flux modulators made from full laminations have been implemented in the previous work. This paper investigates the torque performances of magnetic gear with different configurations of the modulating ring that are characterized by the shape of modulator, the position of interconnecting bridge, and the ratio of pole arc to pole pitch.