电机模态的准确分析是实现电机低噪声驱动设计的重要环节。当电机模态频率与对应阶次径向电磁力波频率接近时，会产生共振。以一台6极36槽的70 kW商务车主驱动永磁同步电机(PMSM)为研究对象，对比分析转子开辅助槽和针对一阶齿谐波的转子分段斜极方法对电磁力波的影响。采用转子开辅助槽和转子分段斜极的优化方法后，0阶12倍频径向电磁力波幅值可减小79%。建立电机三维有限元模态仿真模型，分析电机结构部件对模态的影响，结合常用车载驱动电机的安装固定方式对外壳进行约束，分析不同约束方式下电机的模态特性。结果表明，在峰值功率8 000 r/min的工况下，优化设计方案下的0阶12倍频的径向电磁力波幅值较大，但由于频率为4 800 Hz，远离电机模态的固有频率，因此不会发生共振，降低了电磁噪声。

The accurate analysis of motor modal is an important part to realize the low noise drive design of motor. When the modal frequency of motor is close to the frequency of corresponding order radial electromagnetic force waveresonance will occur. Taking a 6-pole 36-slot 70 kW commercial vehicle owner driven permanent magnet synchronous motor as the research objectthe influence of the rotor with auxiliary slot and the rotor with segmental skewed pole method for the first-order tooth harmonic on the electromagnetic force wave is compared and analyzed. The amplitude of the 0-order 12-time frequency radial electromagnetic force wave can be reduced by 79% after adopting the optimized method of rotor with auxiliary slot and rotor with segmental skewed pole. The three-dimensional finite element modal simulation model of the motor is established. The influence of the motor structural components on the modal is analyzed. Combined with the installation and fixation methods of the common vehicle mounted drive motorthe shell is constrainedand the modal characteristics of the motor under different constraints are analyzed. The results show that under the working condition of peak power of 8 000 r/minthe amplitude of radial electromagnetic force with 0-order 12-time frequency under the optimized design scheme is largebut the frequency is 4 800 Hzfar away from the natural frequency of the motor modalso resonance will not occur and the electromagnetic noise is reduced.