Study On The Low Speed Torque Performance Of Two-phase Hybrid Stepping Motors With Redundant Windings

As the theory of stepping motor design, manufacturing and control techniques get more and more mature in recent year, the development of stepping motor has made them amongst the topics of significant interest to researchers. However, due to the hash requirements for the aircraft to operate reliability, stability and ect., still there were many key technique issues to be resolved. In this paper, the torque fluctuation phenomenon of two-phase hybrid stepping motor was primarily focused in the field of aerospace applications, and the stepping motor with redundant windings was proved to have the poperties of torque ripple suppression, and the solution to torque stability in low-speed region was highlighted.Firstly, the torque fluctuation phenomenon of two-phase hybrid stepping motor was analysied theoretically, and this periodic fluctuation was found to originate form the motor design, and deteriorates in control procedure. Based on this, the Ansoft Simulation was carried out to verify the effectness of theoretical analysis, and then a method to suppress the torque fluctuation was proposed.Secondely, Targeting at improving the torque stability propertiy in low speed region, the electromagnetic design was specially considered, including moto r structure design, magnet and iron core materials selection, parameter calculation of electromagnetic, and ect.. The electromagnetic design basing on theoretical analysis as mentioned above also agrees well with the technical requirements for two-phase hybrid stepping motor. And the simulation of three-dimensional(3D) finite element analysis(FEA) verifies the rationality of our electromagnetic design. In the meanwhile, the distribution of the magnetic field and its influence to each partial of the motor in the simulated model were analysied.The proposed two-phase hybrid stepping motor with redundant windings was optimized according to phase order on the basis of the motor design, which is devoted to improve the torque density evaluated by an objective function defined in this thesis context, and several important electromagnetic parameters as well as its influence on properties of stepping motor was also detailed auxiliarily. And the static and dynamic performance of this optimal designed motor was futher simulated with 3D-FEA method, and it proved that the post-optimized stepping motor can confirm well to the technique requirements operated under different specified conditions in the field of aerospace applications.Finally, the key factors to improved torque stability of stepping motor in low speed region were confirmed by means of theoretical analysis and 3D electromagnetic field calculation and modeling. And a solution to suppress torque fluctuation and improve motor properties in low speed was suggested according to the analysis results of electromagnetic field calculation and its optimization. A prototype motor with low torque fluctuation was designed, and the proposed optimization design methods can provide an engineered approach for stepping motor.