Noise Optimization of High-Speed Permanent Magnet Motor by Stiffeners

With the increase of permanent magnet motor speed, frequencies of low-frequency and high-amplitude electromagnetic force are closer to the low-order motor modes, resulting in more serious vibration and noise, which further restricts the increase of permanent magnet synchronous motor speed. In this paper, vibration and noise optimization of a high-speed permanent magnet motor for air compressors is analyzed from the point of structural modes. Stiffness of the motor body is improved by using stiffeners to change natural frequencies of main vibration modes. So that natural frequencies of main modes are far away from electromagnetic force frequencies, and the vibration and noise of the high-speed permanent magnet motor is reduced. Results show that natural frequencies of the main vibration modes can be changed effectively by adding annular stiffeners, and the best vibration and noise reduction effect can be obtained by optimizing radial thickness of the stiffeners.