Design And Research Of Bearingless Motor Based On Lorentz Force

Conventional bearingless motor is a motor that integrated the functions of motor and magnetic bearing,with the advantages of magnetic bearing just like no contact,no wear,free maintenance,and high speed.But conventional bearingless motor torque winding and levitation winding are installed on the stator,so result the air-gap magnetic field coupling is relatively serious,therefore the bearingless motor torque and radial levitation force restricted.For this designed a bearingless motor based on the Lorentz force,the bearingless motor is only has a set of stator winding,the permanent magnets on the rotor use of special decorate,its not only the small coupling of torque and axial suspension force,but also greatly improve the axial space utilization of the motor.In view of the designed Lorentz force type bearingless motor,this paper detailed review its working principle,designed the structure of Lorentz force type bearingless motor and the rotor suspended supporting scheme,using the finite element method to study the air-gap magnetic field and the axial suspension force of Lorentz force type of bearingless motor,and designed related experiments.The main content of these paper are as follows:(1)Firstly,introduced the composition of magnetic bearing "no bearing"(the bearingless motor)in motor,on the base of bearingless motor that generate radial levitation force,from the structure improvement and innovation,then design a Lorentz force type bearingless motor that can generate axial active levitation force,meanwhile show the whole supported scheme of rotor,and then put forward the detailed structure design process,given the final structure parameters.(2)Secondly,according to the established structure parameters,its finite element model is established through ANSYS software.By the simulation,the air-gap magnetic field distribution and the axial active levitation force characteristics of bearingless motor is obtained,at the same time,the supported characteristics of permanent magnetic bearing are analyzed.(3)Then,according to Park coordinate transformation,established the decoupling current model of Lorentz force type bearingless motor based on dq0 coordination,the torque current and suspended current is decoupled in form principle,which provided the theoretical basis for the stable operation of the Lorentz force type bearingless motor.Additionally,the axial suspension stiffness of Lorentz force type bearingless motor and suspension stiffness of radial permanent magnet bearings were obtained by using the least squares fitting.(4)Finally,experimental device of Lorentz force type bearingless motor has been presented,then simulated the working process of its,the air-gap magnetic field and the Lorentz force of axial(the active suspension force of axial)were measured,then the experimental measurement results is compared with the simulation value,and analyzed the reasons of those difference.The design theory and relatively characterics of the Lorentz force type bearingless motor were obtained by the research,as a good foundation for subsequent optimization design of Lorentz force type bearingless motor.