Research On Torque Ripple Suppression Strategy For Brushless DC Motor

Brushless Direct Current Motor(BLDCM)has the advantages of simple structure and reliable operation,and is widely used in many fields such as smart home appliances and new energy vehicles.However,due to the structural design and control strategy of the BLDCM,the motor will generate large torque ripples during operation,which not only reduces the stability of the motor,but also limits its application in high-precision applications.In view of the above problems,this paper mainly conducts the following research on the suppression of motor torque ripple.Firstly,the research background and research significance of the brushless DC motor are introduced,the causes of various torque ripples of the motor are briefly described,and corresponding control strategies are proposed.By analyzing the commutation process and working principle of the motor,a mathematical model of the brushless DC motor is established.Secondly,the influence of different PWM modulation methods on torque ripple is analyzed.Aiming at commutation torque ripple caused by phase current lagging back electromotive force and torque ripple caused by non-conductive phase freewheeling,a three-phase PWM modulation method is proposed.Advanced commutation control strategy,build a simulation model in the Matlab/Simulink environment,verify that the control strategy can not only maintain the stability of the non-commutation phase current during the commutation period,but also reduce the torque ripple during the non-commutation period.The simulation results show that this control strategy can effectively suppress the torque ripple of the motor in the whole running process.Thirdly,in view of the fact that the control parameters of the PID controller in the system cannot be updated in real time,which leads to the problems of poor robustness and slow response speed of the electromagnetic torque,on the basis of the control strategy in Chapter 3,the improved gray wolf algorithm(Changed Gray Wolf Optimization,CGWO)optimized fuzzy PID controller instead of traditional PID controller.The problem of slow convergence speed and easy to fall into local optimum in the basic algorithm is solved,and the superiority and feasibility of the improved method are verified by using the test function.The improved gray wolf algorithm is used to optimize the proportional factor and quantization factor of the fuzzy controller,realize the adaptive adjustment of the control parameters,and further improve the pulsation suppression effect of the electromagnetic torque when the operating conditions change.Finally,combined with the above theoretical analysis,a hardware experiment platform based on TMS320F28335 is built,and the design of hardware circuit,main program and interrupt subroutine is completed.The experimental results verify the effectiveness and practicability of the proposed control strategy.