Discussion And Researching Of BLDCM Commutation Torque Ripple Suppression Strategy

Permanent magnet brushless dc motor replaces the mechanical commutation structure and retains the various characters of the traditional dc motor, inhibits the spark, noise and electromagnetic interference caused by brush and commutator. Compared with the traditional electric excitation synchronous motor has more advantages, such as simple structure, small volume, high efficiency, convenient maintenance and good speed regulating performance. There must be rotating electric field to make the Brushless dc motor rotor rotation, in general, Three-phase BLDCM have three phase stator, at the same time, power on one of the two phase, in order to produce a rotating electric field. This method is very easy to implement, But in order to prevent permanent magnet rotor locked by stator, Under the premise of know the precise location of the rotor magnet, Must use a particular way power on the stator Sequentially. During the phase commutation, inductance and counter electromotive force interact with each other, so that it can not commutate immediately, thus generate commutation torque ripple. Commutation torque ripple limits brushless dc motor applied in industrial situations.Firstly, this essay combs the developing process of permanent magnet brushless dc motor and then introduces the development background and research significance of brushless dc motor and the research and application in the electric car. Lastly, briefly analyze and classify the causing of commutation torque ripple of BLDC motor. And then analyzes the work principle and mathematical model of brushless dc motor. Secondly analyzes the suppression principle of commutation torque ripple. Put forward a strategy to reduce the commutation torque ripple from the low-speed level and high-speed level. This method guarantee equal between current decline rate of shutdown phase and current rising rate of opening phase during commutation, thus keep the current of un-commutation stable. Finally, describe the BLDCM applied in electric bicycle.In order to verify the effectiveness of the proposed method of torque ripple, set up real electric bicycle with brushless dc motor control platform for experiment. The simulation and actual brushless dc motor control platform fully confirmed that the proposed strategy effectively suppresses the brushless dc motor commutation torque ripple in electric bicycle. In the end summarized and prospected to this paper. Constructing the platform of brushless dc motor and researching the torque ripple is related to many of the theory, method and technology, so there are many new problems to think and solve. Not only need to accumulation and improvement in the practical application, but also need to do further research and development.