轮毂电机气隙偏心下不平衡电磁力与转子系统振动特性分析

相对于传统电机,轮毂电机在电动车行驶过程中,由于路面激励等外界因素的作用,定转子之间会更容易产生偏心,造成轮毂电机气隙不均匀而产生不平衡磁拉力,影响轮毂电机的运行。以一种表贴式永磁同步轮毂电机为研究对象,建立等效的转子动力学模型。通过解析计算和Maxwell Ansoft软件分析了气隙偏心下轮毂电机电磁力的变化情况,并将不平衡电磁力带入等效转子系统运动方程,运用隐式Newmark积分法对转子系统在不平衡电磁力、质量偏心和初始误差偏心影响下的动力响应进行计算。结果表明:气隙偏心会产生特定频率的不平衡磁拉力,增大质量偏心会减轻不平衡磁拉力对转子系统的影响,并且初始位置误差偏心会使转子轴心朝偏心方向偏移,并会与重力相互作用。研究结果可为分析电动车用轮毂电机定转子的振动和后续的控制奠定基础。

Vibration characteristics and unbalanced electromagnetic force analysis of a rotor for a hub motor with Air-Gap Eccentricity

Compared to conventional motors, During the driving process of the electric motor, the eccentricity is more likely to occur between the stator and the rotor due to external factors such as road excitation, resulting in uneven air gap of the hub motor and unbalanced magnetic pulling force, which affects the operation of the hub motor.A type of surface mount permanent magnet synchronous hub motor was studied in this paper,and an equivalent rotor dynamics model was established. Through the analytical calculation and Maxwell Ansoft software, the variation of the electromagnetic force of the hub motor under the air gap eccentricity is analyzed, and the unbalanced electromagnetic force is brought into the equation of motion of the equivalent rotor system. The dynamic response of the rotor system under the influence of unbalanced electromagnetic force, mass eccentricity and initial eccentricity is calculated by implicit Newmark integral method. The results show that the air gap eccentricity would produce unbalanced magnetic pull force at a certain frequency and increase the mass eccentricity would reduce the influence of unbalanced magnetic pull force on the rotor system, and the initial position error eccentricity would shift the rotor axis toward the eccentric direction, and interact with gravity. The research results can lay a foundation for analyzing the vibration and subsequent control of the stator and rotor of the electric motor hub motor.