Analysis of Vibration and Noise in a Permanent Magnet Synchronous Motor Based on Temperature-Dependent Characteristics of Permanent Magnet

Interior permanent magnet synchronous motors (IPMSMs) are widely utilized due to their high power density. However, noise and vibration issues are often encountered in these motors. While researchers have extensively investigated individual aspects such as noise, vibration, and heat generation in PMSMs, there has been a lack of comprehensive studies examining the interrelationships among these factors. In this paper, a novel approach is proposed for predicting vibration by considering the radial force in the air gap as the exciting force, while also accounting for the changes in the permanent magnet (PM) characteristics caused by heat generation during motor operation. The method involves decomposing and identifying vibration components associated with each vibration mode and predicting noise based on the sound radiation efficiency of each mode. By constructing a vibration map based on current and temperature at a specific frequency, the components most affected by current variations and PM characteristics can be identified. This allows for the proposal of design improvements aimed at reducing vibration. Furthermore, by comparing the vibration map with the noise map, it is confirmed that vibration serves as a source of noise and influences its generation. However, it is found that vibration and noise are not strictly proportional. Overall, a comprehensive analysis of the correlations between vibration, noise, and other factors in IPMSMs is presented in this study. The proposed method and findings contribute to the understanding of the complex dynamics involved and provide valuable insights for the design of quieter and more efficient motor systems.