Partitioned Stator Hybrid Excitation Doubly Salient Machine With Slot Halbach PM Arrays

A new partitioned stator (PS) hybrid excitation (HE) machine with slot Halbach permanent magnet (PM) arrays is proposed in this paper. Due to the adoption of PS structure, its armature winding (AW) is located in the outer stator, and the PMs and the field winding (FW) are housed in the inner stator, thus the space utilization is significantly enhanced. The key difference of proposed machine is that Halbach PM arrays are employed in the inner stator slot openings, so that the parallel magnetic circuit between PM field and wound field is performed and the ratio of PM field short-circuited in the inner stator is effectively reduced. Thus a wider speed regulation region and a higher torque/power density can be achieved. Firstly, the configuration of proposed machine is described, based on which its operating principle is discussed. Then the electromagnetic performances are calculated and compared based on 2-dimensional finite element analysis (FEA). The results show that the torque can be improved by 76% with a similar magnetic field regulation ratio compared with an existing PS-HE machine with slot PMs. Finally, a prototype machine is built and tested to verify the analysis and FEA results.