Vibration and noise analysis of rotor shaft of permanent magnet synchronous motor used in electric vehicles

Permanent magnet synchronous motors (DMSM) are widely used in many industrial applications such as precision robots, aerospace and electric vehicles industries due to their high reliability and high dynamic performance. Despite their advantages, vibration has a significant impact on the performance of DMSM. To ensure efficient and reliable performance of DMSM, the correct material selection for the rotor shaft is critical. In this study, three different rotor shaft materials (AISI 4140, AISI 4340 and AISI 5140) were used to compare the effects of the rotor shaft of DMSM used in electric vehicles on engine vibration and noise. The experiments were carried out in three stages: experimental modal analysis, operational deflection shape (ODS) analysis and noise analysis. Experimental Modal Analysis (DMA) was carried out to determine the dynamic characteristics called modal parameters such as natural frequencies, mode shapes and the amount of damping of the rotor shaft. Finite Element Method (SEM) was used to verify the results obtained by DMA. In the ODS analysis, the experiments were carried out at speeds of 600 rpm, 900 rpm, 1200 rpm and 1500 rpm and under loads of 0 kW, 2 kW, 4 kW, 6 kW and 8 kW using accelerometers placed on the DMSM at specified points. For noise analysis, the sound measuring device was placed in the appropriate position to make measurements from the DMSM. The experiments were carried out at the highest rotor shaft operating speed (1500 rpm) and under 0 kW, 2 kW, 4 kW, 6 kW and 8 kW loads. The overall results show that material selection can play an important role in reducing the vibration and noise of DMSM.