A Multiphysics Approach for NVH Analysis of PMSM Traction Motor 2021-26-0520
Electric vehicles are fast expanding in market size, and there are increasing customer expectations on all aspects of the vehicle, including its noise and vibrational characteristics. Irritable noise from traction motors account for around 15% of the overall noise in an electric vehicle, and thus, has a need to be analysed and studied. This study focuses on identifying the critical vibro - acoustic orders for an 8 pole PMSM (Permanent Magnet Synchronous Motor) for three cases - healthy, with static eccentricity and with dynamic eccentricity. PMSM motors are widely used for traction and other applications due to their higher power density along with compact size. A coupled approach between electromagnetic and vibro - acoustic simulation is deployed to characterise the NVH behaviour of the motor. The electromagnetic forcing that causes this noise is evaluated using a 2D electromagnetic analysis, followed by NVH analysis where critical harmonics and noise levels from the motor are obtained. Prominent noise (more than 70 dB) at human sensitive frequencies (~2.5 kHz) are observed during certain speeds of operation. Also, amplification of critical and neighbouring harmonics due to rotor eccentricity is also observed.