Comparative Studies on Performances of Slotted and Slotless High-Speed PMBLDC Motors

Slotted and slotless stators are two main stator topologies in high-speed permanent magnet brushless direct current (PMBLDC) motors. Both have their own advantages and drawbacks. The electromagnetic loss of slotted and slotless motors have different characteristics in different speed range. Therefore, the comparison of slotted and slotless motors must consider different speed ranges. The performances of slotted and slotless high-speed PMBLDC motors in the full speed range up to 480 krpm are compared in this paper. The no-load and load electromagnetic performances of slotted and slotless motors are studied. The electromagnetic losses of slotted and slotless motors in the full speed range are investigated and compared. Meanwhile, based on the loss calculation results, the thermal characteristics of slotted and slotless motors are studied. The comparison results are summarized considering the electromagnetic, loss and thermal characteristics comprehensively. Finally, a prototype of high-speed PMBLDC motor is manufactured and tested to validate the analysis results.