Research On Static Magnetic Field And Torque Characteristics Of Hybrid Stepper Motor Based On ANSYS

Due to the limitation of computing performance of the computer,2D FEM (Finite Element Method) was always used for the electromagnetic field analysis of the hybrid stepper motor in the past, such as tooth-layer specific permeability method. However, the electromagnetic field of hybrid stepper motor is a typical highly saturated 3D nonlinear electromagnetic field. The magnetic field distribution is very complicated; especially the axial magnetic distribution is not uniform because of the influence of axial magnetizing permanent-magnetic materials installed on the rotor. With the development of computer performance and the application of the universal finite element software,3D finite element analysis of the whole motor magnetic field is practical and feasible. Therefore,3D finite element model of the hybrid stepper motor was set up to analyze static magnetic field and calculate the torque characteristics in this dissertation.Firstly,3D finite element model of two-phase and five-phase hybrid stepper motor is established by the universal finite element analysis software ANSYS, based on the basic of the electromagnetic field theory, to calculate the static magnetic field distribution. Static characteristics, especially the torque-angle characteristics which is very important to the performance of the motor, is further calculated.Then, the torque-angle characteristic calculation program is written, based on the traditional tooth-layer specific permeability method, to calculate the torque characteristics of the above two-phase and five-phase hybrid stepper motor. Then, the calculation results are compared with ANSYS calculation results and the experimental results. The study found that, the calculation precision of ANSYS calculation method is obviously improved.An enhanced two-phase hybrid stepper motor which has permanent-magnetic materials installed in the stator slots is introduced in this dissertation.3D finite element model of the motor is established by ANSYS to calculate the torque-angle characteristics, and then compared with the same type standard two-phase hybrid stepper motor. The study found that, the static torque of Enhanced hybrid stepper motor is greatly increased. And the torque production mechanisms are further analyzed. Optimization design of enhanced hybrid stepper motor tooth layer structure, air gap and properties of the stator slot permanent-magnetic materials are carried out, based on the target of maximum static torque output and improve torque-angle characteristics curve waveform.