新能源汽车电机控制器盖板模态优化与振动噪声

Mode optimization of the motor controller cover in a new energy vehicle and its vibration noise analysis

新能源汽车驱动电机成为中国新能源汽车产业发展规划中的关键技术零部件,进而对车用电机的噪声、振动与声振粗糙度(noise,vibration and harshness,NVH)水平提出更高要求。分析了三合一电驱动总成噪声源和传递路径,并研究电机控制器盖板模态频率及刚度和电驱动总成噪声的关联性。然后建立电控盖板的模态优化求解模型,使用Hyperwork软件的Optistruct模块得到最优拓扑形态,指导电控盖板结构上增加环向筋和径向筋来提升模态频率和刚度。加筋优化后,电控盖板单体1阶自由模态频率从197 Hz增加到374 Hz,提高了89.8%,而2000 Hz以内的模态阶次数量从14个减少到9个,减少了盖板的共振次数。通过刚度和固有频率的关系式,可知优化后盖板刚度有明显增加。最后通过台架对照试验验证了电控盖板的优化可以减弱盖板的共振和受迫振动。从典型阶次噪声的阶次切片对比中,减速器一级齿轮21阶和二级齿轮13.16阶以及电机的24阶和48阶噪声对应的盖板振动加速度幅值降低3~7 dB,最终有效降低电驱动总成的噪声。

The electric drive motor has become a key technical component in the development plan for China’s new energy vehicle industry.Higher noise,vibration and harshness(NVH)performance of motor is required.The noise source and transmission path of the integration motor were analyzed,including the correlation analysis between the mode of the motor controller cover and the noise of the drive motor.Then the mode optimization model of the motor controller cover was established,and the Optistruct module of Hyperwork software was used to improve the mode frequency and stiffness by designing hoop and radial ribs on the cover.After optimization,the first-order free mode frequency of the motor controller cover increases from 197 Hz to 374 Hz(89.8%),and the number of mode orders within 2000 Hz is reduced from 14 to 9,thus reducing the number of resonances.According to the relationship between the stiffness and natural frequency,it shows that the stiffness of the cover is significantly increased after optimization.In the end,it is verified by comparative experiments that the optimized motor controller cover could mitigate resonances and forced vibrations.The amplitude of vibration acceleration of the motor controller cover reduces by 3-7 dB corresponding to the reducer’s 21st order of the first gear,the 13.16st order of the second gear,and the motor’s 24st and 48st orders.As a result,the noise of the drive motor is effectively reduced.