复杂行驶工况下四轮毂电机电动汽车机-电-磁-固耦合垂向振动机理研究

Electric vehicle independently drived by four in-wheel motors becomes the important development direction of future electric vehicles with its advantages of typical structure, safety, energy saving. However, under complicated conditions, the speed and the driving torque that the vehicle required are different, which leads to the serious coupling vibration problems of electric vehicles, such as harmonic order vibration and judder during starting, which has negative effects on the stability and the ride comfort. In previous studies on coupling vibration of electric vehicles, few focused on the mechanism of mechanical, electrical, magnetical and solid coupling vibration in vertical direction of electric vehicle excited by four in-wheel motors under complicated driving conditions..This project aims to investigate the problem of mechanical, electrical, magnetical and solid coupling vibration in vertical direction of electric vehicles. Firstly, the mechanical, electrical, magnetical and solid coupling model of a single in-wheel motor will be proposed to analyze the order feature and the variation law of transient electromagnetic forces, including torque, radial electromagnetic force and axial electromagnetic force in three directions. Secondly, the dynamics model of the electric wheel is set up in order to analyze characteristics of magnetism and solid coupling vibration of electric drive wheel in case of eccentricity and inclined eccentricity caused by road excitation. Finally, the dynamics model of electric vehicle is proposed to reveal mechanism of mechanical, electrical, magnetical and solid coupling vibration in vertical direction of electric vehicle excited by four in-wheel motors. The anticipated results of this project will provide a theoretical underpinning and a scientific foundation for vehicle system design and kinetics control.

四轮毂电机电动汽车以在结构、安全和节能方面的突出优势成为未来汽车的重要发展方向。然而，在复杂行驶工况下，车辆对四个轮毂电机的转速和驱动力矩需求不尽相同，导致四轮毂电机电动汽车的阶次振动和起步抖动等耦合振动问题突出，影响了车辆的平顺性和舒适性。以往电动汽车耦合振动研究中，对复杂行驶工况下四轮毂电机多振源耦合激励下电动汽车的机-电-磁-固耦合垂向振动机理较少涉及。.本项目拟研究复杂行驶工况下四轮毂电机电动汽车机-电-磁-固耦合垂向振动问题。建立轮毂电机机-电-磁-固耦合模型，分析三向瞬态电磁力（转矩、径向电磁力、轴向电磁力）的阶次特征和变化规律。建立电动轮磁固强耦合模型，分析路面动态激励引起周向偏心和倾斜偏心下电动轮磁固强耦合振动特性。建立电动汽车机-电-磁-固耦合垂向振动模型，揭示四轮毂电机多振源耦合激励下电动车耦合振动机理。本项目预期成果将为车辆系统设计和动力学控制提供理论基础和科学依据。

四轮毂电机电动汽车以在结构、安全和节能方面的突出优势成为未来汽车的重要发展方向之一。然而，在复杂行驶工况下，车辆对四个轮毂电机的转速和驱动力矩需求不尽相同，导致四轮毂电机电动汽车的阶次振动和起步抖动等耦合振动问题突出，影响了车辆的平顺性和舒适性。以往电动汽车耦合振动研究中，对复杂行驶工况下四轮毂电机多振源耦合激励下电动汽车的机-电-磁-固耦合垂向振动机理较少涉及。.本项目主要完成研究工作及成果如下：.1）轮毂电机气隙磁场解析建模和超薄开路气隙磁场直接测试实验研究。考虑了低次谐波电流、高次边带谐波电流、静态偏心、动态偏心等因素，提出了定子静止坐标系和转子运动坐标系下轮毂电机气隙磁场的解析模型，揭示了空间阶次和幅频特性。发明了一种可探测旋转电机0.1mm数量级超薄气隙磁场测试装置，验证了所提模型。.2）轮毂电机不平衡磁拉力解析建模及特性分析。应用复数相对磁导法和麦克斯韦张量法，建立了静态偏心故障和动态偏心故障的轮毂电机的不平衡磁拉力动态解析模型，分析了定子和转子的不平衡磁拉力的时频特性，揭示了不同偏心率对不平衡磁拉力的影响规律。.3）路面不平度和不平衡磁拉力动态耦合激励下电动轮磁固耦合特性研究。建立了电动轮垂向振动力学模型和数学模型，对比分析了路面不平度和不平衡磁拉力动态耦合激励下电动轮的垂向振动特性。.4）非平稳工况下四轮毂电机电动汽车纵向-垂向耦合振动特性研究。基于轮毂电机可变开关频率矢量控制模型，建立了四轮毂电机电动汽车纵向-垂向耦合振动的16自由度力学模型和数学模型。结合实验研究，分析了路面不平度和不平衡磁拉力动态耦合激励下车辆纵向-垂向耦合振动特性。轮毂电机不平衡磁拉力将引起车辆hpn/60和kf±hpn/60的垂向阶次振动。.本项目成果对于揭示复杂行驶工况下四轮毂电机电动汽车机-电-磁-固耦合垂向振动机理、耦合过程、耦合变量变化规律具有重要的理论意义，为四轮毂电机电动汽车研发奠定了理论基础。