Research And Realization Of BLDCM Torque Ripple Suppression Strategy In Industry

With the rapid development of industry,energy conservation and efficiency have become the main themes of development.As an indispensable member of industrial production,the status of the motor is also more and more important.Permanent magnet brushless DC motor is widely used in various control systems due to its advantages of high precision,high speed,high efficiency and wide adjustable range.Brushless DC motors have the same mechanical characteristics as conventional brush DC motors.The difference is that brushless DC motors use electronic commutation instead of mechanical commutation,which greatly improves the commutation accuracy and reduces the cost of the motor,therefore they have been widely used in many fields of industry.This thesis first describes the permanent magnet brushless DC motor body structure,to determine the Hall sensor as the system position detection device.At the same time,the working principle and commutation process of permanent magnet brushless DC motor are introduced.And the mathematical model and the equation of motion of the motor are established,and the equivalent circuit is obtained.In this thesis,the causes of the torque ripple of permanent magnet brushless DC motor and its suppression methods are mainly studied in two aspects,and the controller of the motor is designed.In view of the reason that the torque ripple produces,this text has mainly analyzed two kinds,one kind is the torque ripple caused by the free-wheeling diode of the non-conducting phase,and the other is the torque ripple caused during commutation.Aiming at the torque ripple caused by Non-conducting phase diode freewheeling,the PWM-ON-PWM modulation method is used in this thesis.The simulation waveforms and the experimental waveforms are obtained.In view of the torque ripple caused by commutation,,This thesis adds the inhibition method of commutation time compensation based on PWM-ON-PWM modulation method,that is,by extending the turn-off time of one of the phase switch to make it the same as the switch-on slope of the other phase switch,and thus Eliminate torque ripple during commutation.On this basis,the thesis builds the simulation model through PLECS software and obtains the final simulation result.We analyze software and hardware based on the design of the controller,.The software function of this text is realized through DSP&CPLD.DSP is the main control chip,the choice of TI's TMS320F28377,and CPLD is the auxiliary control chip,the choice of ALTERA's EPM570T10015.Through the programming in DSP and CPLD,realize the software control function of the controller.The hardware design of this thesis mainly includes the following circuits:drive circuit,detection circuit,power circuit,display circuit,protection circuit and so on.After the hardware and software design is completed,experiments were carried out in laboratories and factories,and experimental waveforms were obtained.The results show that the suppression method used in this thesis can restrain the torque ripple.