Research On Axial-Flux Permanent Magnet Brushless Disk Servo Motor With SMC-Si Steel Composite Iron Cores

In recent years,with the upgrading of industry and the demand of industrial development,intelligent manufacturing and industrial robot industry are booming.Servo motor is one of the core components of industrial robot,which is limited by the installation space and weight of each joint of robot.How to further reduce the volume and weight of servo motor and improve the power density and torque density has become a new research direction.Compared with the current common radial flux permanent magnet(RFPM)motor,the axial flux permanent magnet(AFPM)motor has the characteristics of short axial length,light weight,small volume,high torque density and high torque/moment of inertia ratio,which is suitable for high-end servo field.At present,the stator core of the common axial flux disk permanent magnet motor in the market is mostly wound by silicon steel sheet.Because of the two-dimensional magnetic circuit structure of silicon steel sheet,the end of its winding is prominent relative to the stator in the radial direction,occupying the motor space without energy conversion,which hinders the further improvement of the torque density of the axial flux motor.Soft magnetic composite(SMC)is a new material made by powder metallurgy technology,which is formed by the outer insulation layer of iron powder particles,and can be molded into a complex shape of motor core according to the specific use.Compared with silicon steel sheet,SMC has the characteristics of magnetothermal isotropy.Because of its unique manufacturing process,SMC is suitable for motors with three-dimensional magnetic circuit structure,which is conducive to innovation of motor structure and improvement of motor torque density.But at the same time,compared with silicon steel sheet,SMC material also has the disadvantages of low permeability,high iron consumption under normal working frequency and low mechanical strength.Based on the complementarity of SMC material and laminated silicon steel sheet material in ferromagnetic and mechanical properties,this paper studies and analyzes the double stator axial flux disc permanent magnet brushless servo motor with SMC Si steel composite core,innovates the assembly process of the motor,improves the performance of the motor,and has theoretical significance and practical value.The main contents of this paper are as follows:(1)Briefly describe the research background and significance of this topic.It includes the development background of industrial robot and intelligent manufacturing,the research status of axial flux permanent magnet motor at home and abroad,the research status of SMC material permanent magnet motor and the main content of SMC-Si steel composite core disk motor designed in this paper;(2)The principle,structure,performance and preliminary design of SMC Si steel composite core disk permanent magnet brushless servo motor are studied.Firstly,the principle and structure of SMC Si steel composite core disk permanent magnet brushless servo motor is introduced,and then the electromagnetic scheme of commercial radial flux permanent magnet brushless servo motor is analyzed.Based on this commercial servo motor,the electromagnetic design of AFPM motor with SMC-Si steel composite core is studied.At last,the performance of AFPM motor with SMC-Si steel composite core is compared with that of AFPM motor with silicon steel;(3)The cogging torque of SMC-Si steel composite core disk motor is analyzed and optimized to reduce the torque ripple under rated operation.Including the analysis of torque ripple and cogging torque,three design variables that affect cogging torque are proposed,and the change rule of cogging torque and back EMF is analyzed by simulation.The three design variables are optimized by the method of response surface model and genetic algorithm,and the optimization results are obtained and verified by simulation;(4)According to the previous analysis and optimization design,make and test the prototype.Including the assembly of the prototype,no-load power generation experiment,load experiment,temperature rise experiment and the comparison with the simulation results.The feasibility and superiority of the design scheme are verified.