全电直驱集成动力系统扭振固有特性灵敏度分析及动力学设计

Sensitivity Analysis and Dynamics Design of Natural Characteristic Torsional Vibration of Integrated Electric Power System

为全面掌握纯电动汽车动力传动系统扭振固有特性,提高系统的平顺性,对系统扭振特性进行深入研究,以一种新型全电直驱集成动力传动系统为研究对象,提出了综合考虑电机电磁刚度、齿轮时变啮合刚度等因素耦合作用的建模方法,建立并验证了8自由度力学分支模型,计算和分析了系统的固有频率和振型;基于直接求导法对固有频率进行灵敏度分析,改进了集成系统特征参数,并联合仿真分析了参数优化前后系统的动态变化。结果表明:考虑电磁刚度可得到"零阶"固有频率,能呈现丰富的动力学现象;低阶振动表现在车轮、车身位置,高阶振动表现在变速器部分。基于灵敏度分析结果,系统对应的临界转速5 097 r/min,超出了常用转速范围;电机轴角加速度频域响应最大波动幅值减小了25.9%,整体波动幅值明显减小;变速器输出轴最大波动转速减小了0.26%。此研究成果可为机电耦合系统的固有特性与灵敏度分析提供理论参考。

To understand the inherent characteristics of torsional vibration of pure electric vehicle powertrain and improve the ride comfort of the system,the torsional vibration characteristics of the system was analyzed in depth.Taking a new-type integrated electric power transmission system as the research object,a modeling method considering the coupling of electromagnetic stiffness of the motor and time-varying meshing stiffness of the gear was proposed,and the 8 degree of freedom mechanical branching model was established and verified.The natural frequency and mode shape of the system were calculated,and the analysis results were verified by automatic dynamic analysis of mechanical systems.Based on the direct derivation method,the sensitivity of the natural frequency was analyzed,the characteristic parameters of the integrated system were improved,and the dynamic changes of the system before and after the parameter optimization were examined in simulation.Results show that the“zero order”natural frequency can be obtained by considering the electromagnetic stiffness,showing abundant dynamic phenomena.Low-order vibration is shown in the position of wheel and body,and high-order vibration is shown in the transmission part.Based on the sensitivity analysis results,the critical speed of the system is 5097 r/min,which exceedes the common speed range.The maximum fluctuation amplitude of motor shaft angular acceleration response in frequency domain is reduced by 25.9%,and the overall fluctuation amplitude is obviously reduced,the maximum fluctuation speed of transmission output shaft is reduced by 0.26%.The results provide a theoretical reference for the inherent characteristics and sensitivity analysis of electromechanical coupling system.