基于Preisach模型的永磁同步轮毂电机损耗及温度场建模与分析

针对永磁同步轮毂电机运行过程中发热明显，严重影响永磁体性能和电机寿命的问题。开展电机铁心材料磁滞特性试验，测试一维磁化条件下的磁滞回线，考虑不同磁场强度和磁场高频特性对磁滞特性的影响。考虑到经典Preisach理论无法解释磁场频率过高的现象，基于对称小回环（Symmetric minor loops， SML）的密度函数离散化方法建立高频磁场强度变化的磁滞特性模型，通过与试验结果的对比发现该方法预测结果准确，对于在不同频率下的磁化特性有很好的模拟效果。根据铁心损耗的影响因素分析，提出考虑旋转磁化影响、磁密谐波影响的铁心损耗旋-交系数计算铁心损耗。最后建立电机三维温度场模型，仿真计算不同工况下各个部件的温升情况及危险点，并在试验台上进行电机温升试验，与仿真结果进行对比验证。仿真结果电机温度最大值为73.2℃，试验最高温度为72.6℃，证明电机损耗计算以及温度场仿真的准确性。研究结果表明，考虑磁场强度和磁场频率对铁心磁化特性的影响，能有效改善电机电磁计算中的缺陷，提高电机电磁场、损耗及温度预测的准确性。

Modeling and Analysis of Loss and Temperature Field in Permanent Magnet Synchronous In-wheel Motor Based on Preisach Theory

In view of the problem that the obvious heating during the operation of permanent magnet synchronous in-wheel motor, which seriously affects the performance of permanent magnet and the life of motor The hysteresis characteristic test of motor core material was carried out to test the hysteresis loop under the condition of one-dimensional magnetization, and the influences of different magnetic field intensities and magnetic field high-frequency characteristics on the hysteresis characteristic were considered. Considering the classical Preisach theory fails to explain the phenomenon of high magnetic field frequency, based on the Symmetric minor loops (SML) density function of discretization method to set up the hysteresis characteristics of high frequency magnetic field intensity change model, compared with the results of prediction is found that the results are accurate, the magnetization characteristics under different frequencies have good simulation effect. Based on the analysis of the influencing factors of core loss, the spin exchange coefficient of core loss considering the influence of rotating magnetization and magnetic density harmonics is proposed to calculate the core loss. Finally, a three-dimensional temperature field model of the motor was established to simulate and calculate the temperature rise of each component and its danger points under different working conditions, and the temperature rise test of the motor prototype was carried out on the test bench to verify the comparison with the simulation results. Simulation results show that the maximum temperature of the motor is 73.2℃, and the maximum temperature of the test is 72.6℃, which proves the accuracy of motor loss calculation and temperature field simulation. The results show that considering the influence of magnetic field intensity and 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.