Experimental Evaluation of an Electric Powertrain for NVH
Examensarbete för masterexamen
Applied mechanics (MPAME), MSc
The conventional Internal Combustion (IC) powertrain is now being replaced by alternative, low-emission options, such as the electric powertrain. As a result, the tonal noise and vibration spectrum of the powertrain, previously masked by the IC engine, have become more prominent in the electric powertrain, necessitating an NVH (Noise, Vibration, and Harshness) analysis of the electric powertrain. Previous studies by Vignesh  and Anujit  utilized a CAE (Computer-Aided Engineering) model to examine the NVH behavior of the electric powertrain under various motor and gearbox excitations, concluding that the highest contribution to the vibration and noise response comes from the motor’s torque ripple and the transmission error from the motor. The present study aims to experimentally analyze the NVH behavior of the powertrain and assess the outcome of the earlier study. The experimental evaluation is being carried out by measuring the vibration, noise, and input shaft speed of the powertrain under different load conditions. The measurement response is then analyzed using the order analysis using fixed sampling method to obtain different acceleration and noise responses of the powertrain with respect to various excitations and their associated orders. The response of the powertrain is studied and compared with the CAE model’s behavior. The comparison between the NVH response of the powertrain obtained from ROMAX model and experimental data yield comparable results. The ROMAX model demonstrated a good correlation with the experimental data for the gearbox excitations. However, for the NVH response from torque ripple, the ROMAX model tended to overestimate the response, even though the peaks in the response align with those in the experimental data. Conversely, the NVH response from the motor’s radial and tangential forces were underestimated in the ROMAX model. These observations suggest that the ROMAX model of the powertrain provides a reasonable approximation of NVH response, although fine-tuning the model to better represent the experimental data would yield better results.
Electric powertrain , Noise, Vibration, and Harshness (NVH) , Order Analysis