| High power density permanent magnet synchronous motor,simple structure,wide speed range,with the development of new energy vehicles and rail transportation industry,the application of permanent magnet synchronous motor is becoming more and more popular,because the pursuit of high power density permanent magnet synchronous motor,the characteristics of the internal cooling condition is relatively poor,so the internal permanent magnet motor rotor and its high temperature rise easily at run time,cause irreversible rotor damage or permanent magnet demagnetization,thus affecting the motor to work properly,reducing the life of the motor running,serious can lead to motor lose working ability,and calculation and analysis of permanent magnet synchronous motor temperature rise is very necessary.This paper does the following research:(1)Two theoretical bases for temperature field calculation of permanent magnet synchronous motor are studied.A water-cooled permanent magnet synchronous motor with rated working conditions of 45 k W and 3500 rpm was taken as a prototype.The two-dimensional electromagnetic simulation software Maxwell was used to establish the two-dimensional electromagnetic model of the motor,and the motor loss was calculated and analyzed.By studying the influence of temperature rise on the material properties of the motor,the specific influence of temperature on the loss is calculated.The influence of PWM high harmonic current on motor loss is studied.The external characteristic curve of the motor is analyzed to obtain the loss distribution of the motor under different working conditions.(2)The 3d temperature rise calculation model of the motor with Fluent,the finite element simulation software,was used to calculate and obtain the corresponding temperature rise parameters,and the temperature rise distribution of the motor under rated working conditions was preliminarily calculated.On this basis,a magnetic-thermal bidirectional coupling model is established,and an initial temperature of the material is set.The local temperature rise obtained by the calculation is taken as a reference for modification of material properties,and fed back to the electromagnetic field for iterative calculation until the temperature field of the motor converges.The influence of the change of the inlet velocity and initial temperature of cooling water on the temperature rise of the key parts such as the permanent magnet of the motor was studied.A prototype is taken as the experimental object to conduct the temperature rise experiment,and the results are compared with the simulation results to provide the basis for the accuracy of the simulation results.(3)On the basis of the above loss and temperature rise calculation,were studied and analyzed under the rated conditions and variable condition of the stator loss,tuning of rotor loss and loss of permanent magnet for permanent magnet motor,stator and stator winding temperature directly influence,in-depth analysis and research of the relationship between the motor loss and the temperature rise,provide motor loss optimization has the reference value. |
