Modeling and Analysis of Temperature Field of Permanent Magnet Synchronous Motor Considering High Frequency Magnetic Field Characteristics

The vehicle permanent magnet synchronous motor has the advantages of high power density, compact structure and small size, which makes it generate heat obviously in the process of energy conversion, which seriously affects the service life of the motor and the performance of permanent magnet. Predicting magnet temperature is a challenging task, in lab and various specialized applications, infrared sensors or thermocouples are used to measure the temperature, but it cost a lot. In order to predict the temperature field of the motor, the hysteresis characteristic test of the core material of the motor is carried out in this paper. The hysteresis characteristic and loss of electrical steel under different temperature, magnetic field intensity and magnetic field frequency are tested. It is found that the loss of electrical steel increases with the increase of magnetic induction intensity and magnetic field frequency. Then based on the Preisach theory, the hysteresis model of the core material is established, and analyses the advantages and disadvantages of the limiting magnetic hysteresis loop density function separation method and the symmetric minor loops density function of discretization method. Finally, a three-dimensional temperature field model of the motor was established to simulate and calculate the temperature rise of each component, and the temperature rise test of the motor was carried out on the test bench to verify the comparison with the simulation results. The experimental results and simulation results are basically consistent to prove the accuracy of motor loss calculation and temperature field simulation. The main conclusions of this paper show that considering the influence of magnetic field intensity and magnetic field frequency on the magnetization characteristics of the core can effectively improve the defects in the electromagnetic calculation of the motor core and improve the accuracy of the prediction of the electromagnetic field, loss and temperature of the motor, which is of great significance for the design and control of the motor.