Research On Optimization Of Noise And Vibration Of Vehicle Permanent Magnet Brush Direct Current Motor

Permanent Magnet Brush Direct Current Motor(PMBDC)has the advantages of simple structure,low processing and assembly cost,reliable operation etc,is widely used in automobile and industrial equipment and other fields.is an environmental protection and energy-saving Motor with a good development prospect.In the structure of permanent magnet brush dc motor,the tangential force between the permanent magnet and the rotor core will produce the cogging torque,which will cause the torque fluctuation,cause the vibration and noise of the motor,affect the performance of the motor,and make it difficult for the motor to run smoothly.Therefore,the research of this paper starts from the structure of permanent magnet brush dc motor and looks for a method to weaken the cogging torque,which is of great significance to optimize the vibration and noise of permanent magnet brush dc motor.In order to optimize the vibration and noise of the motor,the causes of the vibration and noise of the permanent magnet brush dc motor are analyzed from three aspects: mechanical noise source,aerodynamic noise source and electromagnetic noise source.The structure of permanent magnet brush dc motor is thoroughly analyzed and a new type of permanent magnet brush dc motor rotor with auxiliary slots on the rotor teeth is proposed.Based on the mechanism of coasting torque and combining the energy method and Fourier decomposition method,the mathematical analytical formula of coasting torque of permanent magnet brush dc motor with auxiliary slots on the rotor teeth is derived.The Maxwell2 D module of finite element simulation software Ansoft was used to analyze the number,position,notch width,depth and shape of the auxiliary slots on the rotor teeth,so as to obtain the influence of the parameters of the auxiliary on the cogging torque.The torque waveform obtained from the simulation analysis is Fourier transformed to obtain the harmonic spectrum under different parameters of the auxiliary groove.Finally,the amplitude of each harmonic in the harmonic spectrum is calculated by the Total Harmonics Distortion,and the THD values of the relevant parameters of different auxiliary channels are obtained.In combination with the variation rule of the cogging torque and THD with the related parameters of the auxiliary groove set on the rotor teeth,a group of auxiliary groove parameters were reasonably selected under the optimal condition of the motor's cogging torque and THD value.A permanent magnet brushless dc motor prototype with an auxiliary slot on the rotor teeth was made,and the vibration and noise of the sample motor were tested.The experimental results show that setting an auxiliary slot on the rotor teeth can effectively reduce the cogging torque and optimize the vibration and noise effects of the permanent magnet brushless dc motor.