Research On Reducing Noise Of Small Permanent Magnet Brushless DC Motors

Permanent magnet brushless DC motor not only has simple structure, reliable operation of AC,but also has the high efficiency, no excitation current and speed performance of DC,it is currently one of the fastest growing class of motor, and has been widely used in household appliances,industrial electric vehicles, aerospace and other fields of power transmission control system. But the vibration and noise of brushless DC motor generated by the operation of the system, to a certain extent, limit application and promotion to the brushless DC motor.Currently, researches focused on motor noise in induction motors and electrical excitation synchronous motors,but not much in brushless DC motor.The air gap flux density of Brushless DC motor determines the waveform and amplitude of induced electromotive force, and induced electromotive force of the stator windings determines the performance of the brushless DC motor. Magnet chamfering within a certain range can not only save permanent magnet materials, reduce costs, but also effectively weaken the cogging torque, improving air gap magnetic of brushless DC motor,and by improving the air gap magnetic field waveforms reduced the radial force between the magnetic field in each harmonic, reducing electromagnetic noise.Moreover, effective motor control circuit can effectively suppress the current exchange mutations and torque ripple generated by the motor,it is significant to improve characteristics of brushless DC motor.Therefore, this paper combines permanent magnet brushless DC motor and control circuit, analyses and research a vibration and noise motor for household appliances. On the one hand, the relationship between different chamfered with gap magnetic and cogging torque analyzed by analytical method, compared and analysed the edge of the permanent magnets of different sizes by the finite element analysis software Maxwell2D, find the best cutting angle; on the other hand, with automatic lead angle function, low noise, high efficiency TB6556FG chip and IPM module TP4124AK, to achieve180°sine wave control of permanent magnet brushless DC motor.Finally, make a prototype and test results, the results with the simulation results very close, not only significantly inhibited the vibration and noise of the motor, but also improve the inverter power factor, now the program has been successfully used in a household appliances.