Research On Electromagnetic Vibration Analysis And Suppression Method Of Permanent Magnet Motor

Permanent magnet brushless motor is widely used in military and civil life because of its small size,high reliability and high power factor.With the increasing application of permanent magnet motors and the continuous improvement of science and technology,people have higher and higher requirements for various performance indicators of motors.The problems of low service life and high noise of permanent magnet motor caused by electromagnetic vibration have also attracted the attention of motor manufacturers and motor researchers.In this paper,an 8-pole 24-slot permanent magnet brushless motor is taken as the research object.Based on the electromagnetic field analysis,the two-dimensional finite element calculation is carried out by Ansys Maxwell software to obtain the space-time spectrum of air gap flux density and electromagnetic force wave.Based on the analytical analysis method,the order and frequency of the electromagnetic force wave are determined,and the influence of the zero-order force wave on the vibration of the motor is analyzed for the radial electromagnetic force,which lays the foundation for the later research.Compared with the finite element calculation results,the reliability of the analytical method is verified.Then,the three-dimensional model of the motor is established in Ansys workbench.Through the modal analysis of the motor stator core and the whole machine,the modal vibration mode and the natural modal frequency are obtained,and compared with the main order electromagnetic force wave to determine whether the motor resonates.On this basis,the harmonic response analysis of the motor is carried out to obtain the variation curves of vibration velocity and displacement with frequency at different positions of the motor.The influence of single-order force wave including zero-order radial electromagnetic force and motor speed on motor vibration is discussed and analyzed.The correctness of the research method is verified by the vibration experiment of the prototype.Finally,in order to reduce the radial electromagnetic force and torque ripple under the condition of ensuring the efficiency of the motor,the multi-objective optimization of permanent magnet motor is carried out with the motor slot parameters(Bs1 and Bs2),pole-arc coefficient and magnetic steel eccentricity as variables.In the optimization,the influence of each variable on each target is obtained by variable parameterization analysis,and the appropriate range of variables is sought.On this basis,the multi-objective optimization of the motor is further completed based on the Taguchi iterative method,and the final motor optimization scheme is determined.The simulation results show that the optimized motor can effectively reduce the electromagnetic vibration under the condition that the efficiency of the motor is slightly improved,and the torque ripple is also reduced,making the motor run more stable.