Design Of High Overload Permanent Magnet Motor For Robot

Permanent magnet synchronous motor has the advantages of high power density,large torque density,strong overload capability,high efficiency and small volume.It is widely used in aerospace,industrial robots,electric vehicles and other fields.With the development of China’s "2025 Plan",the industrial robot industry is developing rapidly,and the requirements of industrial robots for permanent magnet synchronous motors are getting higher and higher.Conventionally designed motors cannot meet the high requirements of the robot industry.In this situation,this paper studies and designs the permanent magnet synchronous motor for robots.The research background and significance of the selected topics are expounded.The types of driving motors for robots and the advantages of permanent magnet motors are introduced.The performance indexes of various permanent magnet servo motors for robots are analyzed.The domestic and international research and development of permanent magnet synchronous motors for robots are reviewed,including the research status of key technologies such as overload capability,permanent magnet motor design,loss reduction and temperature rise.Summarize the reasons for the development gap between domestic and foreign robots,and lead to the main research content of this paper.Firstly,the factors affecting the overload capacity of permanent magnet synchronous motor are analyzed.Starting from the basic formula of electromagnetic torque,the parameters affecting the overload capacity of the motor,such as back-EMF and cross-axis reactance are found.The effects of different rotor magnetic circuit structures on the overload capacity of the motor are compared and analyzed,and the effects of structural parameters such as stator inner diameter and air gap length on the overload capacity are studied.Then the influence of the relevant structural parameters on the overload capacity of permanent magnet synchronous motor is analyzed.Secondly,a high overload permanent magnet motor for robot is designed.The parameters of stator outer diameter,magnetic circuit structure,stator crack ratio and air gap length are compared and analyzed in detail,which ensures the design requirement of 5 times overload capacity of the motor.By means of pole slot matching and unequal air gap,the torque ripple is reduced while the output capacity is guaranteed.Through the finite element method,the designed motor is simulated and analyzed,and the curves of key parameters such as no-load back-EMF,airgap flux density and output torque are obtained.The overload capacity of the designed motor is verified by using input current parameterization.The finite element simulation results show that the designed motor can achieve 5.26 times overload capacity.Again,a 3D model of the permanent magnet motor is created and the thermal conductivity,density,and specific heat capacity of the various parts of the motor are found.The permanent magnet motor loss is calculated,and the eddy current loss of the permanent magnet is optimized by the permanent magnet segmentation.The eddy current loss is reduced by 75.9% under the 5times overload condition.The permanent magnet motor loss is assigned to the corresponding position to calculate the birth heat rate.The steady-state temperature field and the transient temperature field are calculated in the finite element software,which proves that the temperature rise of each part of the designed motor is within a reasonable range.Finally,the paper concludes with a summary of the research work in this paper.The main research contents and conclusions of this paper are summarized,and some design experiences of permanent magnet motors with high overload capability are proposed.