Carrier Electromagnetic Vibration of DC Voltage Fluctuation in Permanent-Magnet Synchronous Motor With Distributed Winding

In this article, we evaluate the noise and vibration in a permanent-magnet synchronous motor (PMSM) with distributed winding driven by voltage source pulsewidth modulation (PWM) inverters. Although the PMSM is a widely used device in a variety of fields, it tends to generate electromagnetic noise and vibration due to the PWM inverters. We describe the frequency of the electromagnetic vibration to estimate the worst point of the carrier electromagnetic vibration of dc voltage fluctuation. The PWM voltage harmonics and the modulation degree of dc voltage fluctuation were investigated through a theoretical analysis of the PWM voltage harmonics. It was found that a modulation degree near 0.56 was the maximum point of the doubled component of the carrier frequency $2f_{c}$ . Compared with the dc voltage fluctuation at this point, the dominant component of the PWM voltage harmonics was near frequency $f_{c}$ at a lower voltage and near frequency $2f_{c}$ at a higher voltage. These tendencies of the carrier electromagnetic vibration of dc voltage fluctuation are also verified in an experiment.