A Comprehensive Analysis of Electromagnetic NVH in Electric Powertrain

In this paper, a comprehensive analysis of NVH in electric powertrains due to electromagnetic sources including spatial-harmonic and time-harmonic components is presented. On the one hand, the spatial harmonics component of a traction motor, which is dependent on the motor geometry, rotor poles, stator teeth, and slots, contributes to the electromagnetic forces from the motor and thus impacts the NVH performance in the electric powertrain. On the other hand, the time-harmonic component in the injected current of a traction motor impacting the NVH performance is a result of the power electronics inverter circuit, the motor control, and the inverter gate modulation strategy. However, it is not necessarily straightforward in one simulation model to include both components considering the fact that spatial harmonics and time harmonics results are usually solved in different domains. This paper aims to present a complete workflow of electromagnetic NVH analysis for electric powertrains covering both spatial harmonics and time harmonics components. The spatial harmonics component is obtained through a 2D electromagnetic finite element tool GT-FEMAG and presented as the result of flux linkage with respect to dq-axes current and rotor position. The time harmonics is obtained through a time-based simulation tool GT-SUITE and presented as the result of current injected in the motor. A set of operating points on the torque-speed boundary of an example traction motor are selected and the corresponding results are presented. The comparisons of the analysis results between the model considering spatial harmonics and time harmonics and the model without considering the harmonics components are presented, and the supplementary details in the outcome confirm the significance of the integrated workflow.