车用永磁同步电机的电磁噪声特性

电动汽车牵引用永磁同步电机要求具有低速大转矩和高速恒功率的运行能力,低速大转矩运行工作点的大电流和高速弱磁导致的磁场畸变可能会导致作用于电机结构的电磁力幅值增大,容易引发较大的电磁振动噪声,从而影响电动汽车的NVH性能。本文基于Ansys多物理场有限元分析平台,研究一台20k W车用永磁同步电机的电磁噪声特性。分别建立电机的电磁场有限元模型和定子结构的3D模态有限元模型,通过仿真得出作用于电机定子齿部的电磁激振力和电机结构的低阶径向模态频率;从电磁力和电机结构两方面分析可能引发较大电磁噪声的主要来源。通过对电机定子结构的振动响应有限元仿真,得到电机定子结构的振动响应频谱;最后通过声场的有限元仿真分析车用永磁同步电机的电磁噪声特性。

Electromagnetic Noise Characteristics of Permanent Magnet Synchronous Motor Applied in Electric Vehicle

Magnetic field distortion caused by the larger current in low speed high torque or the weak magnetic field in high speed lead to increasing of electromagnetic force amplitude, so electric vehicle traction motor with the low speed high torque and high speed constant power operation ability is apt to cause large electromagnetic noise and vibration, which affects the comfort of the car. Based on Ansys multi-physics platform, the electromagnetic noise analysis of a 20kW permanent magnet synchronous traction motor is researched. The electromagnetic field finite element model and the stator structural 3D model were established to obtain the electromagnetic excitation force acting on the stator teeth and the low order radial mode frequency, the main source of large electromagnetic noise can be analyzed from two aspects of electromagnetic force and motor structure. The vibration response spectrum of the stator structure was obtained through the finite element simulation of the vibration response of the stator structure. Finally, the electromagnetic noise characteristics of the permanent magnet synchronous motor were analyzed by using the finite element simulation of the sound field.