Research On Recognition Of Electromagnetic Noise And Vibration Of Permanent Magnet Synchronous Machine

It is well known that noise and vibration of permanent magnet synchronous machines (PMSM) are important targets used to estimate operation performance, which have also been difficult problems. Through the research on identification technique to noise and vibration source, the design scheme of PMSM is optimized or the maximum noise and vibration source is identified when it is working. So the useful method is adopted to decrease the noise and vibration. It is significant for improving the performance of machines, shortening development cycle and decreasing cost.As the innovation team project of LiaoNing province (2006T100), the effect on noise and vibration source supplied by sine wave and inverter are researched, and the eigenfrequency of air gap magnetic field, normal electromagnetic force, noise and vibration are investigated. Some theoretical significances and practical values are obtained as follow:Firstly, the air gap magnetic field and normal electromagnetic force supplied by sine wave and inverter are analyzed. The regularity between inverter switching frequency and stator current harmonic frequency is summarized by experiments, and the expressions of air gap magnetic field frequency and inverter switching frequency is deduced by 3D motional magnetic field Finite Element Method (FEM) calculation and analysis. Then the regularity of pole-slot match effecting on normal electromagnetic force wave order is analyzed, and the analytical expressions of normal electromagnetic force wave order resulting from integral and fractional slot winding is obtained. The analytical expressions of normal electromagnetic force wave order and frequency supplied by inverter is deduced.Secondly, the regularity of normal and tangential electromagnetic force effecting on electromagnetic noise and vibration of PMSM is investigated, and the program of electromagnetic noise calculation is compiled. The normal electromagnetic force is the main reason of noise and vibration by analysis, the vibration of PMSM is caused by cogging torque, but it has a little influence on noise. The electromagnetic noise calculation program is suitable for comparison of multi-schemes, and the calculation is accurate and timesaving. Then the effect on noise and vibration source due to eccentricity is analyzed, the expressions of normal electromagnetic force and eigenfrequency of noise and vibration under condition of static eccentricity and dynamic eccentricity.Thirdly, the transient acoustic field FEM of PMSM is investigated, and the experiment characteristic is analyzed. The spectrum of experimental stator current supplied by inverter is analyzed, and the time current harmonic loaded in stator winding, so 3D motional magnetic field of PMSM supplied by inverter is calculated. Using normal electromagnetic force instead of air-gap flux density by the Maxwell's Law, and then applied it on the surface of stator in order to calculating the transient acoustic field supplied by inverter. Because the air-gap magnetic field harmonic content depends on pole-slot match, which effects acoustic field peak frequency, so the effect of integral and fractional slot winding on air-gap magnetic field and 2D acoustic field are calculated and analyzed by FEM.Fourthly, through analysis for mechanism of noise and vibration and eigenfrequency expressions, the identification program for source of noise and vibration is compiled. The time domain signal of noise and vibration is analyzed by this, the noise and vibration source, which results in peak frequency of noise and vibration, can be identified. So the relevant method can be adopted to decrease the noise and vibration of PMSM.