Research On The Homopolar Stator Permanent Magnet Bearingless Slice Motor

Since the permanent magnets of traditional bearingless permanent magnet motors are placed on the rotor,not only is it difficult to dissipate the heat,but also the costly permanent magnets are fragile.This paper takes a Homopolar Stator Permanent Magnet Bearingless Slice Motor(HSPMBSM)as the research object,the operation mechanism and decoupling performance were explored,then the structure was optimized.Finally,a prototype was developed for experiments,which laid a theoretical foundation for the further research of the motor.Firstly,it takes 12/4HSPMBSM as the research object,and then analyzes the operation mechanism of the motor.The virtual work method was used to derive the motor levitation force and torque expressions.From the expression,it was found that when the motor pole pair number P ≥ 3,the motor was decoupled from each other in levitation force control and torque control.According to the levitation force expression,it can also be obtained that the harmonic component of the air gap magnetic density generated by the levitation winding energization will cause the levitation force to fluctuate.Therefore,this paper uses a "quasi-sinusoidal" winding to reduce the levitation magnetic flux harmonics,thereby reducing the levitation force fluctuations.Electromagnetic field simulation shows that HSPMBSM has good decoupling performance,and compared with the use of three-phase suspension windings,the levitation force fluctuations of the "quasi-sinusoidal" suspension windings have decreased by 40.09%.Then use the theoretical calculation method and the finite element calculation method to design the size parameters of the 12/4HSPMBSM prototype.The installation scheme of the sensor is proposed,and the feasibility of the installation scheme of the Hall sensor is verified by simulation.Subsequently,in the Isight multidisciplinary optimization design platform,an optimization design method combining approximate model and optimization algorithm was used to optimize the rotor tooth parameters.The final torque fluctuation is reduced by 45.36%,and the suspension force fluctuation is reduced by 4.54% in the case of "quasi-sinusoidal" winding.The average torque and suspension force can also meet the working requirements.Finally,an HSPMBSM prototype was developed,built a motor control platform with d SPACE simulation controller.The experiment successfully achieved a stable rotating suspension of the motor.When the speed reached 4000 rpm,the rotor vibration displacement did not exceed ± 75 um,which fully verified the feasibility of HSPMBSM.