一种降低无刷直流电机非导通相续流的PWM调制方式研究

A PWM Modulation Method for Reducing the Non-conduction Phase Freewheeling of Brushless DC Motor

无刷直流电机转矩波动会影响电机运行平稳性,降低系统效率,产生噪声。本文针对非换相期间转矩波动进行分析,重点研究了PWM调制造成的转矩波动。当逆变器的开关管处于关断时,非导通相的续流是造成非换相期间转矩波动的主要因素。经过理论推导,证明了当控制系统采用PWM-ON-PWM调制方式时,非导通相续流可被完全消除。通过Simulink仿真及实验验证了该方法可完全消除非导通相续流,降低转矩波动。

The torque fluctuation of the brushless DC motor will affect the stability of the motor operation,reduce the system efficiency,and generate noise.This paper analyzed the torque ripple during non-commutation and focuses on the torque ripple caused by PWM modulation.When the switch tube of the inverter is off,the freewheeling of the non-conducting phase is the main factor that causes torque fluctuation during the non-commutation phase.After theoretical derivation,it is proved that when the control system adopts PWM-ON-PWM modulation mode,the non-conducting phase freewheel can be completely eliminated.It is verified by Simulink simulation and experiment that this method can completely eliminate non-conducting phase freewheeling and reduce torque ripple.