Influence of number of poles, magnet arrangement, and current density on characteristics of inner and outer rotor PMSMs

Permanent magnet synchronous motors (PMSMs) have been increasingly used in various applications for their small size and high efficiency. There are two major classes of PMSMs. One is the inner rotor type (IR type) PMSM, which has the rotor on the inside and the stator on the outside. The other is the outer rotor type (OR type) PMSM, which has the rotor on the outer side of the stator. In this paper, the characteristics of seven kinds of IR type and OR type motor structures are compared by changing the magnet arrangement, number of poles, and current density.