Design Of High Speed Permanent Magnet Motor And Thermal Analysis Based On Magneto-thermal Coupling

The advantages of high speed and high power density of high-speed motor enable it to effectively reduce the utilization rate of materials and save costs.Meanwhile,high-speed motor can be directly connected with high-speed load,which can save the intermediate speed changing device,and then can effectively reduce the noise generated by the working system and the corresponding friction loss,so as to improve the transmission efficiency of the working mechanism.Because of the above advantages of high-speed motor,it has a good application prospect in many fields,including energy storage flywheel mechanism,cycle refrigeration application,high-speed grinder processing,new textile and so on.But at the same time,because of these characteristics of high-speed motor,compared with traditional motor,there are some technical difficulties in the research and design which conventional motor does not have,and therefore this paper studies and analyzes a 150 KW,20000r/min high-speed permanent magnet synchronous motor,mainly on three technical aspects of the motor,which are electromagnetic design,loss calculation and temperature calculation.The main research contents can be divided into the following three parts.First of all,according to the characteristics of high-speed motor,the selection and design of its stator and rotor structure and the calculation of its main size parameters are completed,Through the analysis of the stator core structure,winding distribution,core material,rotor pole number,rotor outer diameter and length,permanent magnet material and other parts of the motor,and combined with the finite element analysis software,the electromagnetic design of the high-speed permanent magnet motor is carried out,so that the parameter size and material of each part of the motor can be determined.After that,the finite element simulation model is established to analyze the characteristics of the studied motor,and the corresponding characteristic curves of the motor are obtained to verify whether the design content is reasonable.Secondly,the loss calculation of the designed high-speed motor is carried out,and the specific work content is the research and analysis of the magnetization characteristics of the motor stator core.On this basis,the calculation model of the stator iron loss is constructed,which takes the influence of harmonic and rotating magnetization into account.The analytical calculation of the stator iron loss of the designed motor is completed through the model,and the analytical results and finite results are obtained.The two results of the iron loss obtained are compared and verified;the copper loss of the winding of the designed motor is calculated according to the analytical formula of the copper loss of the winding;the calculation model of the wind friction loss is built in the finite element fluid field,and the analysis model of the wind abrasion of the motor is simulated and calculated.At the same time,the wind friction loss of the motor is divided according to the factors of the rotor speed and the surface roughness of the rotor.Simulated calculation of eddy current loss of permanent magnet is completed in two-dimensional field.Finally,the temperature field of the designed motor is calculated,and a cooling model of the motor is established.Using the finite element calculating way in which the analysis model of the temperature can be setting to calculate the temperature in the three-dimensional fluid.Afterwards,the temperature field analysis model of the motor is established by the method of magneto-thermal coupling,considering the influence of temperature change on the material properties of each part of the motor,and the interaction between the electromagnetic field and the temperature field is analyzed comprehensively,and the temperature distribution result closer to the actual operation is calculated.