Abstract: The whine noise of a battery electric vehicle accelerating to 70 km/h seriously affects the sound quality of the vehicle. Combined with the vehicle subjective and objective test evaluation, it is found that the 6th order electromagnetic noise contributes to the problem. The mechanism analysis of this noise is carried out by means of modal test, semi-anechoic chamber bench test and so on. It is determined that the mechanism is the forced vibration caused by the deviation of the co-axiality of the motor stator and rotor, which lead to the uneven magnetic density of the air gap, resulting in the peak of the electromagnetic 6th order vibration at 450 Hz, and the 6th order noise is further amplified through the resonance of the upper cover of the controller. In order to effectively solve the problem of electromagnetic 6th order noise, the optimization of the motor stator processing technology and the controller cover are implemented from the two aspects of noise source and transfer path, and the effectiveness of the scheme is verified by semi-anechoic chamber experiments. It provides valuable experience and engineering value for noise, vibration, harshness (NVH) performance of the electric drive of battery electric vehicles.

Key words: Battery electric vehicle; Electric drive; Electromagnetic noise; NVH

摘要： 某纯电动汽车加速至 70 km/h 出现的啸叫问题，严重影响整车声品质。通过整车主、 客观测试评价，锁定啸叫来自电机电磁 6 阶噪声。对此噪声产生的机理分析，通过模态试验、 半消声室测试等手段，确定其机理为电机定转子同轴度偏差导致气隙磁密不均引起的强迫振 动，从而导致电磁 6 阶振动在 450 Hz 处峰值凸出，并通过控制器上盖共振将 6 阶噪声进一步 放大。为有效解决电磁 6 阶噪声问题，从噪声源头和传递路径两方面，实施了电机定子加工 工艺优化和控制器上盖优化措施，经半消声室实验验证了方案的有效性。为后续纯电动汽车 电驱总成的噪声、振动与声振粗糙度（NVH）性能开发，提供了宝贵的经验和工程价值。

关键词: 纯电动汽车；电驱总成；电磁噪声；NVH