摘要：无刷直流电机在换相区和传导区均会存在转矩波动大、输出转速稳定性差的问题，严重影响了其工程应用效果。通过对电机转矩脉动的理论分析和Buck变换器的工作原理分析，提出一种基于Buck变换器的无刷直流电机四闭环控制方法。该方法在三相桥前级增加Buck变换器的基础上，对电机转速、相电流、Buck变换器输出电压和电感电流进行闭环控制。该方法能够消除传导区转矩脉动，削弱换相区转矩脉动。在Matlab/Simulink仿真环境中建立基于Buck变换器的无刷直流电机闭环控制系统模型，并分别对无Buck变换器控制方法和基于Buck变换器的四闭环控制方法进行仿真。结果表明，基于Buck变换器的四闭环控制方法能完全消除无刷直流电机传导区转矩脉动，换相区转矩脉动减小75%。
关键词：无刷直流电机；Buck变换器；转矩脉动

Abstract: Permanent magnet brushless DC motors (PMBLDCM) have simple structure and great torque.Based on the mathematical model of BLDC motor,taking three phase six state working mode as an example,the commutation torque ripple and the PWM torque ripple of the BLDC motor were analyzed in detail.A new control topology structure which adds a Buck converter before the three phase bridge was proposed.The closedloop control system of BLDC motor based on Buck converter was established.The simulation model of the control system was built by using the control system simulation software Matlab/Simulink.The correctness of theoretical analysis was proved by simulation results.
Key words: BLDC motor;Buck converter;torque ripple