Comparison Between Π-shaped and T-shaped Doubly Salient Permanent Magnet Machines with High-order-harmonic Armature Winding

In this paper, a comparative study between two doubly salient permanent magnet (PM) machines with $\pi$-shaped stator iron core segments and that with T-shaped stator iron core segments is presented. Firstly, based on magnetic modulation theory, the armature winding is artfully designed, where the high-order-harmonic is utilized to achieve a higher winding factor. With the unique armature winding design, the output torque of two motors can be improved. Then, the global optimizations of two motors are conducted to make full use of PMs. The optimization result shows that by considering the winding design along with the stator core segment, reduced PM usage can be achieved to produce the approximate torque. Finally, the electromagnetic performances of the two motors are compared with finite element analysis, which shows that the $\pi$-shaped motor can achieve 25% higher torque than the T-shaped motor with the same usage of PM.