Desing And Analysis Of High Temperature And High Power Density Permanent Magnet Synchronous Motor

In special fields such as aerospace,electric vehicles and oil fields,not only the drive motor is required to have a higher power density,but also its harsh working environment puts forward higher requirements on the high temperature resistance of the motor.To this end,this paper takes high temperature and high power density permanent magnet synchronous motor as the research object.The surface-mounted permanent magnet synchronous motor with an equivalent ambient temperature of 120℃ and a power density of not less than 3kW/kg was designed and optimized.Corresponding solutions are given for the problems of permanent magnet demagnetization and torque reduction that will occur in high temperature environments,and on this basis,a complete set of design of high power density permanent magnet synchronous motor based on multi-physics coupling is proposed method.The design method of multi-field coupling makes the designed permanent magnet motor take into account the requirements of electromagnetic,mechanical and temperature characteristics at the same time.The main research contents are as follows:First,the entire analytical design process of permanent magnet synchronous motor based on equivalent magnetic circuit method is introduced.The structure of the permanent magnet synchronous motor is selected,including the inner rotor structure and the rotor magnetic circuit structure.The main dimension parameters of the design of permanent magnet synchronous motor are derived.And obtained the specific parameter design scheme in the motor design process.including stator winding design,stator iron core structure design.air gap height design and the selection of fixed rotor material.Secondly,the modeling method of electromagnetic-temperature-stress multiphysics permanent magnet synchronous motor is constructed.Through the electromagnetic field analysis of the basic electromagnetic characteristics of the motor under no-load and load conditions,the preliminary design of the motor structure is completed.Analyze the temperature field distribution of the motor under rated load loss through the temperature field,and verify whether the motor thermal design is reasonable.Through stress field analysis,verify whether the strength of the motor permanent magnet meets the requirements at high temperature and high speed.Then,based on the requirements of high power density,low torque ripple and high torque density of permanent magnet synchronous motors.The influence of different aspect ratio,split ratio,stator slot type,permanent magnet array structure and weight reduction slot size on multi-field characteristics is analyzed.Through research and comparison,the correspondence between motor size and performance is obtained,and then the optimized Motor size.Finally,the optimization results show that on the premise of meeting the temperature and stress requirements,the average torque in the electromagnetic field of the motor has increased by 0.51%,and the torque ripple and cogging torque have decreased by 46.27%and 60%,respectively.The addition of the weight-reducing slot further reduced the actual weight of the motor by 6.7%,which resulted in the overall power density reaching 3.12kW/kg,which fulfilled the design goal.