Research On Vibration And Noise Of Permanent Magnet Brushless Motor For Mountain Bike

In today's green life,electric mountain bike more and more favored by consumers.Electric mountain bike is a kind of high?grade fitness leisure tool,which has higher requirements on the vibration and noise of the motor.In this paper,the permanent magnet brushless(PMBL)motor for electric mountain bike is used as a compound driving mode,that is,the use of the square wave current control for the PMBL motor when the mountain bike starts,and use of the sine wave current control when it travels.The vibration and noise of the PM Brushless DC motor are studied in this paper.Firstly,this paper introduces two kinds of common PMBL motors,which are flat top brushless motors and sine wave brushless motors,and the finite element simulation,modal analysis,vibration and noise finite element simulation of two kinds of motors are carried out.In order to study the influence of the support on the motor,the intrinsic modal finite element analysis is carried out for the different core positions and different support structures.Then,the paper introduces the two driving modes of the PMBL motor,which is the sine wave current control mode and the flat top wave current control mode,and compares the current harmonics and torque ripple under the two kinds of two control modes.In order to compare and analyze the vibration characteristics of two kinds of control modes,the finite element simulation of vibration under different current driving is carried out,and concluded that the larger the vibration is caused by the harmonic current.In order to verify this conclusion,the harmonic current in the ideal sine wave current injection and square wave current is compared.Finally,a 300 W prototype is made,and the performance of the prototype is tested,which verifies the correctness of the finite element electromagnetic design.In order to verify the correctness of the finite element analysis method of modal,the modal experiment is carried out,and the experimental results are compared with the simulation results.Through the use of different control mode of the prototype,respectively,the no?load and load conditions of the vibration and noise experiments,and compared with the simulation results to verify the motor vibration and noise finite element analysis method is correct.