Researches On Electromagnetic Vibration And Noise In Permanent Magnet Synchronous Motor

Since the characteristics of the permanent magnet synchronous motors are superior, they have been increasingly used in production practice.However,electromagnetic vibration and noise of permanent magnet synchronous motor restricts the permanent magnet synchronous motor applied in production practice better.Therefore, the research on permanent magnet synchronous motors electromagnetic vibration and noise is meaningful. For analysis of Electromagnetic Vibration and Noise of research Permanent Magnet Synchronous Motors, the following studies are carried out:Firstly, in order to carry out the excitation source of the electromagnetic vibration and noise, the radial and tangential air gap magnetic density formula are prepared by using the field calculator. Then it brings about the calculation formula of radial and tangential electromagnetic force density. The simulations,work out of radial and tangential air gap magnetic flux density waveform and obtain the density of radial and tangential electromagnetic force density spectrum waveform,are for later research.Secondly, the natural modes of stator core and the whole motor are calculated, results show that the structure of stator core and the whole motor are both reasonable since the natural frequencies of the stator core and the whole motor have avoided the electromagnetic wave frequency which have prevented the occurrence of resonance. Loading electromagnetic force onto the stator teeth, and carrying out multi-physical field coupled process in order to solve the electromagnetic vibration and noise, results show that the vibration of the motor is more obvious when the frequency is low, while small vibration occurs when the frequency is high; the radial vibration is larger than the tangential vibration. From the simulation results of the noise field, it comes to the conclusion that the noise decreases with the increase of the distance, and the motor noise is controlled within a rational range.Again, the paper studies the influence on a permanent magnet synchronous motor electromagnetic vibration and noise after weakening cogging torque. After elaborating on the basic theory of cogging torque, weakens the cogging torque by eccentric magnet and magnetic rotation. Subsequently, the simulation has solved the radial and tangential air gap flux density, and the radial and tangential electromagnetic force density. The analysis results show that weakening of the cogging torque can reduce the motor electromagnetic vibration and noise.Finally, tests and analyzes the permanent magnet synchronous motor electromagnetic vibration and noise. By using hammering method, modal test is carried out. Low order natural frequencies of the motor are obtained. Test and simulation results are basically the same, which proved the reliability of simulation. After testing the motor vibration and noise, the analysis results indicate that weakening of the cogging torque can reduce the motor vibration and noise. Then, the reliability of the theory and simulation is verified.