Characteristic Analysis of Two-Phase Stator-Permanent-Magnet Hybrid Stepping Machines with Radial and Tangential Magnetization

Hybrid stepping machines (HSMs) are preferred in applications where high precision, low-cost positioning and high torque, since they can be controlled with no feedback control and have many advantages of higher torque and efficiency over the other types of stepping machines. In this paper, a stator-permanent-magnet HSM (SPMHSM) with radial magnetization (RM) is proposed and compared with that with Tangential magnetization (TM). Firstly, the structure of proposed machine is introduced and its operation principle is analyzed by describing the variation in the armature magnet field versus current. Secondly, based on the similar electrical load and the amount of PM, the SPMHSM with RM is designed. Thirdly, the electromagnetic performance including back-electromotive force, magnetic density and output torque of the two machines are analyzed. The simulation results indicate the SPMHSM with RM can alleviate the magnetic saturation of stator core, and has a wilder current and torque range.