Influence of Common Mode Voltage Reduction Algorithms on High-Frequency Sideband Vibrations in PMSMs

Space Vector Pulse Width Modulation (SVPWM) induces Common Mode Voltage (CMV) in three-phase Voltage Source Inverters (VSIs). This CMV generates high-frequency sharp edges that can lead to significant leakage currents, which, in drive applications, may accelerate motor bearing degradation and cause winding insulation failure. To mitigate these issues, alternative modulation strategies such as Active-Zero State PWM (AZSPWM) and Near-State PWM (NSPWM) have been proposed in the literature. These techniques aim to reduce CMV and thereby decrease the degradation of electrical drives. This paper analyzes the Noise, Vibration, and Harshness (NVH) performance of AZSPWM and NSPWM compared with conventional SVPWM. The two CMV reduction schemes are tested on interior permanent magnet synchronous motors (IPMSMs) to evaluate their effectiveness in lowering CMV, as well as their impact on high-frequency sideband vibration harmonics. The results show that, although CMV is effectively reduced, vibration levels increase. This indicates that CMV reduction algorithms negatively affect NVH performance, despite mitigating motor bearing degradation and winding insulation failure.