无刷直流电机PWM调制方式对非换相期间转矩脉动的影响

Effect of Brushless DC Motor PWM Modulation Modes on Non-commutation Torque Ripple

针对无刷直流电机非换相期间转矩脉动的问题,分析了非换相期间转矩脉动产生的原因,指出非导通相续流是导致非换相期间转矩脉动的重要因素.对4种调制方式因非导通相续流引起的非换相转矩脉动进行分析,指出不同调制方式转矩脉动产生的时间有所不同.推导并验证了通过PWM_ON_PWM这种调制方法会减小无刷直流电机非换相期间的转矩脉动.以TMS320F2812DSP为控制核心,以180W无刷直流电机为控制对象,通过转速电流双闭环对电机进行控制,测得不同PWM调制方式下的相电流波形图.实验证明,在非换相期间,PWM_ON_PWM调制方式能完全抑制因非导通相续流引起的转矩脉动.

Aiming at the problem of non-commutation torque tipple of brushless DC motor, this paper analyzes the cause of the non-commutation torque tipple in detail, and points out that the diode freewheeling of the inactive phase is an important factor which leads to the non-commutation torque tipple. This paper analyzes the non-commu- tation torque tipple which is caused by the diode freewheeling of the inactive phase in four modulation modes. It points out that the time of the torque tipple is different in different modes of modulation. It deduces and validates that the non-commutation torque tipple of brushless DC motor is decreased by using PWM_ ON_ PWM. Using TMS320F2812 DSP as the core of control and using rated 180W brushless DC motors as the object of control, and controlling the speed and current dual-closed-loop. It measures the waveforms of phase current were measured in different PWM modulation modes. The experimental results prove that PWM_ ON_ PWM can absolutely inhibit the non-commutation torque tipple which is caused by the diode freewheeling of the inactive phase.