| The permanent magnet synchronous motor(PMSM)has the advantages of large power density,small size,high efficiency and good speed regulating performance.In addition,with the development of society,all kinds of automatic intelligent household electrical appliances appear in people's field of vision and are closely related to People's Daily life.Therefore,the size of the vibration and noise of permanent magnet synchronous motor has become one of the indicators to measure the quality of the motor.As the only key component of permanent magnet synchronous motor(PMSM),the vibration characteristics of the rotor during rotation and the influence on the air gap under non-ideal conditions lead to the change of electromagnetic force,which directly affects the working life of the motor and the change of vibration noise.In this paper,the influence of rotor system on the electromagnetic vibration and noise of PMSM is studied as follows.(1)Theoretical analysis of electromagnetic vibration and noise generated by permanent magnet synchronous motor.The relationship between radial air gap magnetic density and radial electromagnetic force,which plays a major role in electromagnetic vibration and noise,is discussed.In this paper,the low order modes of the rotor system structure of permanent magnet synchronous motor(PMSM)and the corresponding natural frequency correlation theory are studied.(2)Based on the theoretical analysis of the rotor eccentric electromagnetic force and torque of PMSM,the analytical model and its finite element model of the rotor static eccentric and rotor dynamic eccentric magnetic field are constructed.The time stepping finite element method is used to analyze the no-load air gap magnetic field,electromagnetic force density and the stator of PMSM with different eccentricity under the two-dimensional static field and transient field respectively The time distribution of the electromagnetic force on the inner surface of the tooth crown is calculated by Fourier analysis,and the harmonic times of the above waveform distribution are calculated.The waveforms under different eccentricity and different eccentricity and the changes of their harmonics are compared,which lays a foundationfor the following study of the vibration displacement and speed of the motor.(3)The three-dimensional simplified model of permanent magnet synchronous motor is constructed.The inherent mode and vibration mode of stator core and rotor system are analyzed by using ANSYS Workbench software.Furthermore,the change of critical speed under different eccentricity is calculated by loading rotary velocity and corresponding bearing constraints on rotor system,and the vibration characteristics of rotor system during rotation are studied.(4)Using harmonic response in ANSYS Workbench The module carries out harmonic response analysis to get the maximum vibration displacement and the maximum vibration velocity curve in all directions under the rated load,static eccentricity and dynamic eccentricity of the permanent magnet synchronous motor motor,and calculates the noise sound pressure level according to the maximum vibration displacement of the stator core,and analyzes the influence of the rotor dynamic and static eccentricity on the time distribution of radial electromagnetic force density Change of electromagnetic vibration and noise caused.This paper analyzes the influence of dynamic and static eccentricity on electromagnetic vibration,summarizes the change rule of unbalanced magnetic pull caused by different eccentricity state and eccentricity degree,and the change rule of vibration displacement in the X,Yand Z axis directions of the outer surface of stator core,which provides reference value for the research of rotor eccentricity fault parameter identification of permanent magnet synchronous motor. |
PDF Full Text Request