Research On The Electromagnetic Vibration And Noise Of Amorphous Alloy Permanent Magnet Synchronous Machines

Amorphous alloy(AA)materials are characterized by extremely low losses.The excellent properties of AA materials offer some possibilities to decrease iron loss and increase efficiency of AA permanent magnet synchronous machines(PMSMs).AA PMSMs will have a broad prospects.However,AA materials have some limitations: low stiffness,high magnetostriction coefficient,low core lamination factor.Therefore,vibration and noise of AA PMSMs can be remarkably increased.This dissertation focus on electromagnetic vibration and noise of AA PMSMs,and the main research contents as follows:The first part studies analytical models of stator core vibration due to magnetostriction.An important source causing vibration of AA PMSMs is magnetostriction effect of magnetic materials.According to magnetic flux distributions of radial flux(RF)and axial flux(AF)motors,analytical models of stator core vibration due to magnetostriction for RF and AF motors are set up based on piezomagnetic equations and newton’s law,respectively.The relationships among physical quantities are obtained.Motor vibration due to magnetostriction is proportional to magnetostriction coefficient.Vibration displacement is approximatively linear with yoke radius and tooth height.The influence of young’s modulus on vibration due to magnetostriction is little.when the frequency of power supply is far away from the natural frequency of the motor,the effect of the frequency of power supply on vibration displacement is little,and vibration velocity is proportional to the frequency of power supply,and vibration acceleration is proportional to the square of the frequency of power supply.Analytical models are programmed,forming computing software.The applicability of the precision and simplified models is analyzed.The simplified model can accurately calculate average of stator yoke vibration,and the precision model can calculate the distribution characteristics of stator yoke vibration.The precision of analytical models is proved by finite element method and AA core experiment.Finally,the distribution characteristics of stator core vibration displacement and stress are obtained by using analytical models.The second part studies the numerical calculation method of motor eletromagnetic vibration and noise.A more systematic calculation method which take into account eletromagnetic forces,magnetostriction effect and lamination compression forces(LCFs)is proposed.This paper interprets the effects of LCFs on vibration and noise from two aspects: on the one hand,LCFs have an effect on the magnetic properties of AA cores(magnetization characteristic and magnetostriction characteristic).On the other hand,LCFs have an effect on the mechanical properties of AA cores(young’s modulus and shear’s modulus parameters).Data for magnetostriction curve of AA materials and magnetization curves of AA stacked and wound cores are obtained experimentally.At the same time,modal experiments of AA stacked and wound cores are carried out and the elasticity modulus parameters are modified by the modal experiments.Electromagnetic vibration and noise of a 2.1kW RF AA PMSM and a 7kW AF AA PMSM are calculated by using the proposed mothod.At the same time,electromagnetic vibration and noise of the PMSMs are calculated under different situations which include only eletromagnetic forces,the combination of eletromagnetic forces and magnetostriction effect.The calculation results using different methods are compared with experimental results,and the comparison results show that the calculation precision is improved obviously by using the proposed method.The third part studies the influence factors of AA core vibration and noise.Processing technics including stacked and wound,immersion and annealing have a large influence on the property parameters of AA cores(elasticity modulus,magnetostriction characteristics and magnetization characteristics),so AA core vibration and noise are greatly effected by processing technics.Meanwhile,the magnetic flux density and frequency have a direct influence on AA core vibration and noise.The measurement device was set up,and AA core samples with different processing technics were manufactured.AA core samples vibration and noise were tested under different magnetic flux densities and frequencies.The influences of magnetic flux density,frequency and different processing technics on AA core vibration and noise are researched and some conclusions are obtained.Stacked AA core vibration is reduced by 8.0-12.7% and increasing amplitude of stacked AA core noise is lesser when compared with wound AA cores under different magnetic flux densities and frequencies.The vibration of AA cores with immersion producing processes is reduced by 12.9-31.3% and the noise by 1.9-4.5%.The vibration of AA cores with annealed producing processes is reduced by 37.8-63.7% and the noise by 4.7-7.8%.The influences of immersion and annealing producing processes on AA core vibration and noise become smaller as the magnetic flux density and frequency increase.AA PMSM vibration and noise can be decreased by using AA stacked cores and AA cores with immersion and annealed producing processes.The fourth part studies the influence factors of motor vibration and noise.There are substantial differences in elasticity modulus parameters among different core materials.At the same time,different core materials differ in the magnetostrictive coefficient.Compressive stress has a large influence on the magnetostrictive coefficient.When the compressive stress reachs a threshold value,the magnetostriction rises rapidly to a high level.Moreover,core lamination factor is effected by core materials and processing techniques.The influences of young’s modulus,magnetostriction coefficient and LCFs on motor electromagnetic vibration and noise are researched and some conclusions are obtained.Motor electromagnetic vibration is inversely proportional to young’s modulus.As the young’s modulus increases,the influence of the magnetostriction effect on motor vibration and noise becomes larger.As the magnetostriction coefficient increases,the influence of the magnetostriction effect on motor vibration and noise becomes larger.The influence of LCFs on AA PMSM vibration and noise is larger than that of SS PMSM,and the influence of LCFs on AF PMSM electromagnetic vibration and noise is larger than that of RF PMSM.Vibration and noise of 2.1kW RF AA and SS PMSMs,7kW AF AA and SS PMSMs which have the same specifications are calculated and tested respectively.The influences of magnetostriction effect and LCFs on vibration and noise for 2.1kW RF AA and SS PMSMs,7kW AF AA and SS PMSMs are obtained.At the same time,the differences of vibration and noise between AA and SS PMSMs are obtained,and the main reason for the differences is elasticity modulus of AA materials is lower,followed by higher magnetostriction coefficient and lower core lamination factor.