Comparative Analysis of Tangentially Magnetized Stator-Permanent-Magnet Hybrid Stepping Machines With Four, Five and Six-Tooth

For applications requiring low-cost positioning and high torque, tangentially magnetized stator-permanent-magnet hybrid stepping machines (TMSPMHSMs) are the preferred choice. Generally, the torque of the machine is related to the number of teeth per stator pole. In order to investigate the effect of the number of stator teeth on the performance of the machine, this paper presents a design of the machines with four, five and six-tooth configurations to be analyzed. Firstly, the topology of TMSPMHSM is introduced, and its operation principle is analyzed. Secondly, the three machines are designed with the same amount of PM and electrical load. The electromagnetic characteristics of the three machines are then analyzed, including back electromotive force, detent torque, output torque and so on. Finally, the results show that the TMSPMHSMs with five and six-tooth have a higher torque under rated condition, while the TMSPMHSM with four-tooth exhibits a wilder current and torque range.