jmag 应用-spm电机的噪声分析

1、Copyright (c) 2007-2008 JRI Solutions, Ltd. All Rights Reserved.1Overview The recent reductions in size and weight of electric motors that have been made possible by new materials has increased the importance of reducing both noise and vibration. There are various sources of noise including electrom

2、agnetic, mechanical, and draft noises. Among these, vibration noise caused by the electromagnetic force can be treated in JMAG. The vibration is particularly large when the frequency of the electromagnetic force is close to a resonant frequency. This note shows an analysis of the sound pressure caus

3、ed by the excitation of the natural modes of vibration of the stator.Sound Pressure Analysis of an SPM Motor2008-05-01JMAG Application Cataloghttp:/jmag.jri-sol.co.jp/en/catalog/Contact ;JRI Solutions, Ltd. Engineering Technology Division JMAG Support Teamcae-infosci.jri-sol.co.jp orDistributor in y

4、our countryJMAG is the registered trademark of the Japan Research Institute, Limited. Other product and service names described or referenced in this text are the trademarks or registered trademarks of their respective owners.Copyright (c) 2007-2008 JRI Solutions, Ltd. All Rights Reserved.2Electroma

5、gnetic force(amplitude), NEigenvalue Analysis The major cause of the vibration noise is the excitation of the first-order eigenfrequency of the stator and the excitation by the electromagnetic force. As a result of the eigenvalue analysis, the first-order eigenfrequency is found to be 1560 Hz.Figure

6、 3 Eigenmode of the Stator Core (1560Hz)Electromagnetic Force Figure 1 shows the distribution of the electromagnetic force in the stator at 0.01667seconds. The force is concentrated at the tooth tips exerting an intensive force in the radial direction. Figure 2 shows the frequency component of elect

7、romagnetic force in the radial direction at the tooth tips. The frequency component of 120 Hz is dominant as shown in the graph.3025201510500 240 480 720 960 1200 1440 1680 1920 2160 2400(Unit:N)Frequency, HzFigure1 Electromagnetic Force at 0.01667 secondsFigure 2 FFT Result of Electromagnetic Force

8、Copyright (c) 2007-2008 JRI Solutions, Ltd. All Rights Reserved.3Sound Pressure Analysis The sound pressure analysis result shows that the sound pressure level becomes maximum at 1540 Hz. As shown in Figure 5, the sound pressure distribution is high around the two opposing areas due to the vibration

9、 in the radial direction of the stator.(Unit: dB)Figure 5 Sound Pressure Level Distribution at 1540 Hz (evaluation point: 0.1m)Vibration Analysis When electromagnetic force is the excitation force, the modal eigenfrequency analysis result shows that the displacement becomes maximum at 1540 Hz. This is because the excitation of frequency component (harmonic of 120 Hz) of electromagnetic